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#1
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Quick Attic Ventilation Question
While calculating the number of soffit vents I am going to install in my
house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#2
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Yes.
"James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#3
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James Bond wrote: While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James You might consider them as half and half for this exercise. As an exercise in logic: The gale end vents will probably act in various ways depending on wind pressure. Soffit and ridge vents would usually act consistently based on the chimney principle. The gable end vents, because they are large and in a vertical surface, would act differently with different wind direction. In any case, look at the Building Science Corporation web site for discussion of venting. This is researched material. TB |
#4
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Complicated fluid dynamics.
At a layman's level, yes, they behave more like exhaust than intake in greater than 50% of the cases. But, the way gable vents work is that air blowing towards one vent creates positive air pressure and the air moving away from the other vent creates negative pressure so one vent is intake and the other is exhaust. Maybe on a perfectly calm day they would both exhaust. Now a ridge vent work similarly. Air blowing over the top of the vent creates a negative pressure area on one side of the vent that sucks the air out of the attic. The replacement air is supposed to come from the soffit vents, thus creating the cold air flow along the rafters that is the design effect. But with the addition of gable vents this make up air will more likely come from the gable vents as intake, not from the more distant soffit vents. That is why it is recommended to do one or the other but not both when it comes to attic venting. And none of this is true all of the time. There are many more variables like orientation of the house, pitch of the roof, design characteristics of each of the vents- alone and in combination, and more. Confused? Join the club. "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#5
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James Bond wrote:
While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James It is really a complex issue. Most of the time (assuming they are located high at the peak) they will act as exhaust. Depending on the wind, temperature of air and deck temperature who knows at any given moment. On occasion they can act as a short cut reducing ventilation. -- Joseph Meehan Dia duit |
#6
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James Bond wrote:
...do my existing gable vents count as intake or exhaust? "Exhaust," worst-case, on a still day, when 16.6Asqrt(HdT) cfm should flow with equal vent area A ft^2 and height diff H feet and indoor-outdoor temp diff dT (F). Nick |
#7
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Can someone explain what a soffit vent is compared to a gable vent?
- Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#8
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A soffit vent is under the lower eaves, at the lowest point in the
attic. They can be either narrow and continuous or else individual larger ones. Gable vents are on the ends of the attic, near the top. |
#9
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See reply inserted-
"James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And Standalone gable vents serve both as supply and exhaust venting. They also provide cross ventilation, especially if aided by the exterior wind conditions. Adding soffit vents makes the equation less accurate. In that case, they act more as exhaust since you're adding supply. just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. Best attic vent system for warm climate areas, in my opinion, is a continuous ridge vent for exhaust. Hardisoffit would serve as the supply whereever soffit is used. You need a minimum of 1" clearance between the attic ceiling insulation and the sheathing for proper soffit supply ventilaiton. If this is blocked, adding soffit vents is futile. |
#10
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Magnusface, Some homes have soffits and others don't. Soffits exist when the roof overhangs the house. Suppose that your house has a gutter and downspouts on the front of your house. If those gutters are flush with the front of your house, then you have no soffits. If on the otherhand, the roof overhangs the front of the house and your gutters are offset a foot or so in front of the vertical surface of the front of your house, then you have soffits. Soffit vents are screen covered opening in the overhang area. If you are on the ground looking up, then you will be looking up at those oval or rectangular openings. Building a house with the soffit overhang is more expensive than building one without. Hence, many homes lack soffits. Now move around to the side of your house which is shaped like a triangle on top of a rectangle. The pointed area at the top of that upper triangle is the gable area. Many homes have large louvered openings in that gable area for attic ventilation. This should provide a good (and free) cross ventilation of the attic. Both types of venting are very useful and they provide good passive (ie, energy free) attic venting. Many astute homeowners add soffits to their homes when they need to add a new roof. This means that the roof must be extended on two sides, but the increase in attic venting is often worth the effort. Of course, good venting can still be achieved without soffits. The killer situation is a home which has no soffit venting and the only other attic venting is extremely undersized gable venting. In that case, the roof sheathing (plywood) will often be worthless after 30 years or so. Gideon =========== Magnusfarce wrote in message ... Can someone explain what a soffit vent is compared to a gable vent? - Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#11
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"Magnusfarce" wrote in message ... Can someone explain what a soffit vent is compared to a gable vent? - Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James Make sure that soffit vents and gable vents are compatible and can live together. It's possible that they might counteract each other and/or disrupt the intended air venting. They will interfere with each other if you have a ridge vent or roof vents. MLD |
#12
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Thanks to everyone for their input. Of course, I am now more confused
than ever. So here is my exact situation. I have an older home in a warm, humid climate (Charleston, SC). Currently, I have gable vents and 2 14" wind turbines for ventilation. It is not enough as evidenced by extreme attic temps in the summer and some curling shingles (especially on the western end of the house, which is oriented such that its long axis is roughly NE to SW). I understand that ridge vents are a great option, but adding them to my roof is cost prohibitive for me at the moment. My thought process was that there is probably little air flow in the lower attic due to all the current venting being up high. Thus, I thought soffit vents would be the answer. It appears, however, that there is a possibility that I could make the situation worse by doing so? Is that right? Should I install soffit vents and block off one or both gable vents? Any further advice would be greatly appreciated. TIA, James "BP" wrote in : Complicated fluid dynamics. At a layman's level, yes, they behave more like exhaust than intake in greater than 50% of the cases. But, the way gable vents work is that air blowing towards one vent creates positive air pressure and the air moving away from the other vent creates negative pressure so one vent is intake and the other is exhaust. Maybe on a perfectly calm day they would both exhaust. Now a ridge vent work similarly. Air blowing over the top of the vent creates a negative pressure area on one side of the vent that sucks the air out of the attic. The replacement air is supposed to come from the soffit vents, thus creating the cold air flow along the rafters that is the design effect. But with the addition of gable vents this make up air will more likely come from the gable vents as intake, not from the more distant soffit vents. That is why it is recommended to do one or the other but not both when it comes to attic venting. And none of this is true all of the time. There are many more variables like orientation of the house, pitch of the roof, design characteristics of each of the vents- alone and in combination, and more. Confused? Join the club. "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James |
#13
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On Mon, 23 May 2005 17:52:07 -0400, James Bond
scribbled this interesting note: Thanks to everyone for their input. Of course, I am now more confused than ever. So here is my exact situation. I have an older home in a warm, humid climate (Charleston, SC). Currently, I have gable vents and 2 14" wind turbines for ventilation. It is not enough as evidenced by extreme attic temps in the summer and some curling shingles (especially on the western end of the house, which is oriented such that its long axis is roughly NE to SW). Composition asphalt shingles on the South and West sides of a house (in the lower latitudes of the northern hemisphere) will always wear faster than those on the other sides of the house because of the exposure to the sun. This is not due to heat in the attic, rather the solar radiation breaking down the organic compounds in the asphalt. I understand that ridge vents are a great option, but adding them to my roof is cost prohibitive for me at the moment. My thought process was that there is probably little air flow in the lower attic due to all the current venting being up high. Thus, I thought soffit vents would be the answer. It appears, however, that there is a possibility that I could make the situation worse by doing so? Is that right? Should I install soffit vents and block off one or both gable vents? Any further advice would be greatly appreciated. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. Or you could install a thermostatically controlled power vent in one of the gable vents, on the inside, that would force air through the attic and out the other end of the house. There are many, many options. TIA, James "BP" wrote in : Complicated fluid dynamics. At a layman's level, yes, they behave more like exhaust than intake in greater than 50% of the cases. But, the way gable vents work is that air blowing towards one vent creates positive air pressure and the air moving away from the other vent creates negative pressure so one vent is intake and the other is exhaust. Maybe on a perfectly calm day they would both exhaust. Now a ridge vent work similarly. Air blowing over the top of the vent creates a negative pressure area on one side of the vent that sucks the air out of the attic. The replacement air is supposed to come from the soffit vents, thus creating the cold air flow along the rafters that is the design effect. But with the addition of gable vents this make up air will more likely come from the gable vents as intake, not from the more distant soffit vents. That is why it is recommended to do one or the other but not both when it comes to attic venting. And none of this is true all of the time. There are many more variables like orientation of the house, pitch of the roof, design characteristics of each of the vents- alone and in combination, and more. Confused? Join the club. "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James -- John Willis (Remove the Primes before e-mailing me) |
#14
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James Bond wrote:
Thanks to everyone for their input. Of course, I am now more confused than ever. So here is my exact situation. I have an older home in a warm, humid climate (Charleston, SC). Currently, I have gable vents and 2 14" wind turbines for ventilation. It is not enough as evidenced by extreme attic temps in the summer and some curling shingles (especially on the western end of the house, which is oriented such that its long axis is roughly NE to SW). I understand that ridge vents are a great option, but adding them to my roof is cost prohibitive for me at the moment. My thought process was that there is probably little air flow in the lower attic due to all the current venting being up high. Thus, I thought soffit vents would be the answer. It appears, however, that there is a possibility that I could make the situation worse by doing so? Is that right? That is right, but it is not common, in most case you will improve the results. A good roofer (not all are good) can tell you quickly with a high degree of accuracy. Should I install soffit vents and block off one or both gable vents? Any further advice would be greatly appreciated. TIA, James "BP" wrote in : Complicated fluid dynamics. At a layman's level, yes, they behave more like exhaust than intake in greater than 50% of the cases. But, the way gable vents work is that air blowing towards one vent creates positive air pressure and the air moving away from the other vent creates negative pressure so one vent is intake and the other is exhaust. Maybe on a perfectly calm day they would both exhaust. Now a ridge vent work similarly. Air blowing over the top of the vent creates a negative pressure area on one side of the vent that sucks the air out of the attic. The replacement air is supposed to come from the soffit vents, thus creating the cold air flow along the rafters that is the design effect. But with the addition of gable vents this make up air will more likely come from the gable vents as intake, not from the more distant soffit vents. That is why it is recommended to do one or the other but not both when it comes to attic venting. And none of this is true all of the time. There are many more variables like orientation of the house, pitch of the roof, design characteristics of each of the vents- alone and in combination, and more. Confused? Join the club. "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James -- Joseph Meehan Dia duit |
#15
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"John Willis" wrote in message ... I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. |
#16
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"MLD" wrote in message news:O9rke.18152$4d6.8881@trndny04... "Magnusfarce" wrote in message ... Can someone explain what a soffit vent is compared to a gable vent? - Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James Make sure that soffit vents and gable vents are compatible and can live together. It's possible that they might counteract each other and/or disrupt the intended air venting. They will interfere with each other if you have a ridge vent or roof vents. MLD WRONG. |
#17
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"Oscar_Lives" wrote in message news:OPvke.2200$PS3.1567@attbi_s22... "MLD" wrote in message news:O9rke.18152$4d6.8881@trndny04... "Magnusfarce" wrote in message ... Can someone explain what a soffit vent is compared to a gable vent? - Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James Make sure that soffit vents and gable vents are compatible and can live together. It's possible that they might counteract each other and/or disrupt the intended air venting. They will interfere with each other if you have a ridge vent or roof vents. MLD WRONG. Don't be too hasty with your answer. The following does not come from the article that I first read but it does point out that there can be conflicts if you have too much of a good thing. Basiically, what I get out of this is that vented air will get it's source from the nearest opening (least resistance) available. This means that if there are gable vents the flow from the soffits will not be too effective. The first article had several schematics that showed the air flow with different systems (gable, soffit and one that had both). The system with the combination of the gable and soffit acted principally as a gable only vented system. Recommendation was to block of the gables if there are soffits. Pay your money and make your choice--but do a bit more research first. Google roof vents, gable vents etc. MLD Watch out for unintended consequences! Murphy's law rears its head in the strangest places... your attic, for instance. Who would think that beautiful powered ventilator might do absolutely nothing to cool your attic? If you have lots of ventilation already, adding a powered ventilator may be a waste of time and money. This is especially true if you have a soffit-ridge vent system, the most efficient natural ventilation system. Face it... ventilators are stupid machines! They will draw air from wherever they can with the least effort. This means that a ventilator will draw air from ridge vents, gable vents or soffit vents. Fine. But if the fan draws much of its air from a nearby gable or ridge vent, there is no benefit to anyone except the electric company! So placement of the ventilator is essential... as well as careful consideration of whether or not it is a wise investment in the first place |
#18
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Okay, so I see it is a very complicated issue. So for my (perhaps) last
question, is there some technique or resonably purchased or rented device that allows me to assess how air is flowing in my attic now and after installing soffit vents? Again, thanks for all the very informative advice. Great group of people around here. Since I now have this old home, I am guessing I will be spending some time around here. James "MLD" wrote in news:aPHke.1315$5b.279@trndny04: Don't be too hasty with your answer. The following does not come from the article that I first read but it does point out that there can be conflicts if you have too much of a good thing. Basiically, what I get out of this is that vented air will get it's source from the nearest opening (least resistance) available. This means that if there are gable vents the flow from the soffits will not be too effective. The first article had several schematics that showed the air flow with different systems (gable, soffit and one that had both). The system with the combination of the gable and soffit acted principally as a gable only vented system. Recommendation was to block of the gables if there are soffits. Pay your money and make your choice--but do a bit more research first. Google roof vents, gable vents etc. MLD |
#19
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If there is a measurable amount of air flow then I guess with a lot of
patience and some way to generate smoke you might be able to make some kind of observation. I can recall on a sand building contest someone made a dragon and made smoke coming out of the nostrils by blowing out something like baking powder using a bulb and plastic tubing. MLD "James Bond" wrote in message ... Okay, so I see it is a very complicated issue. So for my (perhaps) last question, is there some technique or resonably purchased or rented device that allows me to assess how air is flowing in my attic now and after installing soffit vents? Again, thanks for all the very informative advice. Great group of people around here. Since I now have this old home, I am guessing I will be spending some time around here. James "MLD" wrote in news:aPHke.1315$5b.279@trndny04: Don't be too hasty with your answer. The following does not come from the article that I first read but it does point out that there can be conflicts if you have too much of a good thing. Basiically, what I get out of this is that vented air will get it's source from the nearest opening (least resistance) available. This means that if there are gable vents the flow from the soffits will not be too effective. The first article had several schematics that showed the air flow with different systems (gable, soffit and one that had both). The system with the combination of the gable and soffit acted principally as a gable only vented system. Recommendation was to block of the gables if there are soffits. Pay your money and make your choice--but do a bit more research first. Google roof vents, gable vents etc. MLD |
#20
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On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives"
scribbled this interesting note: "John Willis" wrote in message .. . I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis (Remove the Primes before e-mailing me) |
#21
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"John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. |
#22
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"MLD" wrote in message news:aPHke.1315$5b.279@trndny04... "Oscar_Lives" wrote in message news:OPvke.2200$PS3.1567@attbi_s22... "MLD" wrote in message news:O9rke.18152$4d6.8881@trndny04... "Magnusfarce" wrote in message ... Can someone explain what a soffit vent is compared to a gable vent? - Magnusfarce "James Bond" wrote in message ... While calculating the number of soffit vents I am going to install in my house, I am operating on the priciple that I should have equal intake square footage (from the soffit vents to be installed) as exhaust. Now my question is do my existing gable vents count as intake or exhaust? And just to be sure I am using the right term, by gable vent I mean the two triangular vents at each end of my house that are right below the peak of the roof. It is my guess that after the installation of soffit vents that these gable vents would function as exhaust, but I want to verify that. TIA for any help. James Make sure that soffit vents and gable vents are compatible and can live together. It's possible that they might counteract each other and/or disrupt the intended air venting. They will interfere with each other if you have a ridge vent or roof vents. MLD WRONG. Don't be too hasty with your answer. The following does not come from the article that I first read but it does point out that there can be conflicts if you have too much of a good thing. Basiically, what I get out of this is that vented air will get it's source from the nearest opening (least resistance) available. This means that if there are gable vents the flow from the soffits will not be too effective. The first article had several schematics that showed the air flow with different systems (gable, soffit and one that had both). The system with the combination of the gable and soffit acted principally as a gable only vented system. Recommendation was to block of the gables if there are soffits. Pay your money and make your choice--but do a bit more research first. Google roof vents, gable vents etc. MLD Watch out for unintended consequences! Murphy's law rears its head in the strangest places... your attic, for instance. Who would think that beautiful powered ventilator might do absolutely nothing to cool your attic? If you have lots of ventilation already, adding a powered ventilator may be a waste of time and money. This is especially true if you have a soffit-ridge vent system, the most efficient natural ventilation system. Face it... ventilators are stupid machines! They will draw air from wherever they can with the least effort. This means that a ventilator will draw air from ridge vents, gable vents or soffit vents. Fine. But if the fan draws much of its air from a nearby gable or ridge vent, there is no benefit to anyone except the electric company! So placement of the ventilator is essential... as well as careful consideration of whether or not it is a wise investment in the first place WRONG. The Ultimate vented attic would be a suspended roof open on all sides and with a huge hole in the top. You cannot have TOO MANY vents. |
#23
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"Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD |
#24
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"MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. |
#25
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"Oscar_Lives" wrote in message news:803le.7075$PS3.2169@attbi_s22... "MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. I've worked with people just like you---Guess what, they were always the first ones laid off!! |
#26
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"MLD" wrote in message news:1B6le.12$zb.8@trndny06... "Oscar_Lives" wrote in message news:803le.7075$PS3.2169@attbi_s22... "MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. I've worked with people just like you---Guess what, they were always the first ones laid off!! I've worked with people like you. They were the ones who read their horoscopes and asked for validation of their narrow-minded opinions from strangers on newsgroups. |
#27
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"Oscar_Lives" wrote in message news:BW8le.7495$PS3.6906@attbi_s22... "MLD" wrote in message news:1B6le.12$zb.8@trndny06... "Oscar_Lives" wrote in message news:803le.7075$PS3.2169@attbi_s22... "MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. I've worked with people just like you---Guess what, they were always the first ones laid off!! I've worked with people like you. They were the ones who read their horoscopes and asked for validation of their narrow-minded opinions from strangers on newsgroups. Ooops, looks like I stuck a nerve. The truth shouldn't hurt unless it ought to----BTW, where did you meet these people, in the unemployment line?? |
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On Wed, 25 May 2005 17:57:24 GMT, "Oscar_Lives"
scribbled this interesting note: Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. While true, this still begs the question: Is this the best venting that can be obtained or is there a better design? Isn't it possible that a better designed system may, just may have the same or fewer vent openings, the same net free area, and do the job better? I stand by my statement that it is impossible to have "too many" vents. Thank you for your personal opinion. -- John Willis (Remove the Primes before e-mailing me) |
#29
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"MLD" wrote in message news:fk9le.34$zb.27@trndny06... "Oscar_Lives" wrote in message news:BW8le.7495$PS3.6906@attbi_s22... "MLD" wrote in message news:1B6le.12$zb.8@trndny06... "Oscar_Lives" wrote in message news:803le.7075$PS3.2169@attbi_s22... "MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. I've worked with people just like you---Guess what, they were always the first ones laid off!! I've worked with people like you. They were the ones who read their horoscopes and asked for validation of their narrow-minded opinions from strangers on newsgroups. Ooops, looks like I stuck a nerve. The truth shouldn't hurt unless it ought to----BTW, where did you meet these people, in the unemployment line?? "Arguing with someone on the internet is like winning in the Special Olympics.....even if you win you are still retarded" |
#30
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"Oscar_Lives" wrote in message news:xCale.8208$Is4.4601@attbi_s21... "MLD" wrote in message news:fk9le.34$zb.27@trndny06... "Oscar_Lives" wrote in message news:BW8le.7495$PS3.6906@attbi_s22... "MLD" wrote in message news:1B6le.12$zb.8@trndny06... "Oscar_Lives" wrote in message news:803le.7075$PS3.2169@attbi_s22... "MLD" wrote in message news:J80le.1327$Qd3.878@trndny01... "Oscar_Lives" wrote in message news:P2Ske.6500$Is4.5451@attbi_s21... "John Willis" wrote in message ... On Tue, 24 May 2005 01:54:31 GMT, "Oscar_Lives" scribbled this interesting note: "John Willis" wrote in message . .. I'd just install the additional soffit vents and be done with it. If, on the other hand, you were to install ridge vents and soffit vents, then you'd want to close off the gable vents because the ridge vents draw from the source closest to their level. WRONG. You can't have "too much" venting. Leave the gable vents open-- they will help. Do a little more reading on the subject. While it is true that you can't have too much properly designed ventilation, the key is "properly designed." For example, if you have ridge vents, it is best to close off all other vents except the soffit vents, if you want air to be drawn in from the soffits. Why? Has to do with fluid dynamics. There are plenty of sites where you can read up on the issues involved. Here's one that does a good job if discussing many of the factors involved: http://www.factsfacts.com/MyHomeRepair/ventilation.htm Have a good read... -- John Willis WRONG AGAIN. Use your head: The best vented attic would be a suspended roof open on all sides. You cannot have too many vents-- period. This "bypassing" that is talked about (turbines with gables with power fans, etc.) is not harmful to proper venting. The key is to have AT LEAST THE MINIMUM REQUIRED VENTING at the soffits and at the top. However, you cannot have "too much venting", and "bypassing" is not a bad thing. You must be one of the types that listen but don't hear. No one said anything that advocates minimizing the amount of ventilation. What is being tossed around is the best "design solution" to maximizing the amount of ventilation one can expect to get in an attic. In your comment "The best vented attic would be a suspended roof open on all sides"---So what, too simplistic and not an option in a house so forget it. You apparently don't know anything about fluid dynamics--air flow, pressure drop, resistance, path of least resistance etc.. You have no idea what the air flow path will be, without an analysis or experimentation, if you have more than one flow path. Think of an electrical circuit with two or more parallel paths. The current (air flow) will not be the same for each path unless they are all of equal resistance (or do you want to dispute that too). If you take the time to do a bit of reading (just goggle roof vents, or the like) you'll be lead to a number of sources that cover the topic. What you'll learn is that you cannot arbitrarily open up a bunch of holes and expect to get the best ventilation setup. This has been well thought out and one conclusion is that gable vents in parallel with soffit vents are not the optimum solution for a well ventilated attic. Of course if you disagree, that's not a problem but do more than blow your horn---provide some analysis, reference document or any source of information that we can look at----gut feelings don't work when you're trying to solve an engineering problem--and that's what this is whether you recognize it or not. MLD You can't handle the truth. Even when the dreaded "bypassing" is occurring between two vents close to each other, the attic is still being vented. I stand by my statement that it is impossible to have "too many" vents. I've worked with people just like you---Guess what, they were always the first ones laid off!! I've worked with people like you. They were the ones who read their horoscopes and asked for validation of their narrow-minded opinions from strangers on newsgroups. Ooops, looks like I stuck a nerve. The truth shouldn't hurt unless it ought to----BTW, where did you meet these people, in the unemployment line?? "Arguing with someone on the internet is like winning in the Special Olympics.....even if you win you are still retarded" Ambiguous comment--are you referring yourself? BTW, kind of curious at this point--which number is larger--Your hat size or your IQ? |
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