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What size beam to span 14'
I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts.
What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, |
What size beam to span 14'
On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner
wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, I'd check with the building inspector. Local codes may dictate something, especially with snow loads in the north or hurricane winds in the south. . |
What size beam to span 14'
On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner
wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, Can't say from here. Check again with DIYBanter or in Canada. In America I cut a beam down to 22 feet. It hasn't failed yet. |
What size beam to span 14'
"69roadrunner" wrote in message ... I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, -- 69roadrunner Start with local inspector/building permit department. Whatever you may think is acceptable, or what is posted here is worth the paper it is printed on. What is acceptable where I am may not be where you are. Sometimes it makes it a lot easier, and sometimes, it makes the bar higher. Whatever, the man that eventually inspects it is the one who needs to be happy. HTH Steve |
What size beam to span 14'
On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner
wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, How long is each beam? What loads are a part of the 43.3 psf and what is the plf on the beam? Is there any depth of beam restrictions? If so, maybe a glulam product might work better or a dual beam. I think a couple of uploaded construction pics would help explain more here. |
What size beam to span 14'
On Tue, 17 Jul 2012 07:13:33 -0500, "Doug"
wrote: On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, How long is each beam? What loads are a part of the 43.3 psf and what is the plf on the beam? Is there any depth of beam restrictions? If so, maybe a glulam product might work better or a dual beam. I think a couple of uploaded construction pics would help explain more here. Oops, you already answered the first question. |
What size beam to span 14'
"69roadrunner" wrote in message
... I am planning to build a porch roof attached to the back of my house. . . . What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang . . . This requires a building permit (in most jurisdictions.) The municipal or county office that issues building permits can probably answer your question (without charge.) -- Don Phillipson Carlsbad Springs (Ottawa, Canada) |
What size beam to span 14'
On Jul 17, 8:15*am, "Doug" wrote:
On Tue, 17 Jul 2012 07:13:33 -0500, "Doug" wrote: On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, How long is each beam? * What loads are a part of the 43.3 psf and what is the plf on the beam? *Is there any depth of beam restrictions? If so, maybe a glulam product might work better or a dual beam. * I think a couple of uploaded construction pics would help explain more here. Oops, you already answered the first question. *- Hide quoted text - - Show quoted text - There are probably online beam load calculators that could answer the question. But every place I know you would need a building permit to add a porch on to a house. And here to get that building permit you need a drawing signed and stamped by a licensed architect. So, I'd start with finding out what it takes to get a building permit. If it's like here, you'd be wasting your time figuring it out because the architect is going to do it anyway. |
What size beam to span 14'
On Tue, 17 Jul 2012 06:05:14 -0700 (PDT), "
wrote: On Jul 17, 8:15*am, "Doug" wrote: On Tue, 17 Jul 2012 07:13:33 -0500, "Doug" wrote: On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, How long is each beam? * What loads are a part of the 43.3 psf and what is the plf on the beam? *Is there any depth of beam restrictions? If so, maybe a glulam product might work better or a dual beam. * I think a couple of uploaded construction pics would help explain more here. Oops, you already answered the first question. *- Hide quoted text - - Show quoted text - There are probably online beam load calculators that could answer the question. But every place I know you would need a building permit to add a porch on to a house. And here to get that building permit you need a drawing signed and stamped by a licensed architect. So, I'd start with finding out what it takes to get a building permit. If it's like here, you'd be wasting your time figuring it out because the architect is going to do it anyway. I guess you are right because everyone is saying the same thing. I wanted to answer his question directly but just need more info but that will not address the legal aspects of building it. |
What size beam to span 14'
On Tue, 17 Jul 2012 10:06:10 -0500, "Doug"
wrote: There are probably online beam load calculators that could answer the question. But every place I know you would need a building permit to add a porch on to a house. And here to get that building permit you need a drawing signed and stamped by a licensed architect. So, I'd start with finding out what it takes to get a building permit. If it's like here, you'd be wasting your time figuring it out because the architect is going to do it anyway. I guess you are right because everyone is saying the same thing. I wanted to answer his question directly but just need more info but that will not address the legal aspects of building it. The OP is in Canada. |
What size beam to span 14'
On Tue, 17 Jul 2012 08:16:36 -0700, Oren wrote:
On Tue, 17 Jul 2012 10:06:10 -0500, "Doug" wrote: There are probably online beam load calculators that could answer the question. But every place I know you would need a building permit to add a porch on to a house. And here to get that building permit you need a drawing signed and stamped by a licensed architect. So, I'd start with finding out what it takes to get a building permit. If it's like here, you'd be wasting your time figuring it out because the architect is going to do it anyway. I guess you are right because everyone is saying the same thing. I wanted to answer his question directly but just need more info but that will not address the legal aspects of building it. The OP is in Canada. Ooh okay. Though I wanted to help, I do think the local jurisdiction (building dept) could give more help because they will know the loads to consider, foundation tips, etc... . |
What size beam to span 14'
On Tue, 17 Jul 2012 00:53:45 +0000, 69roadrunner
wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Thanks, I would not build anything with a 14 foot span. You'll get eventual sag in the middle no matter what you use, unless it's a steel girder. Use a center post. Seven feet is easy to span and much stronger. |
What size beam to span 14'
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What size beam to span 14'
On Tue, 17 Jul 2012 13:30:23 -0500, wrote:
I would not build anything with a 14 foot span. You'll get eventual sag in the middle no matter what you use, unless it's a steel girder. Use a center post. Seven feet is easy to span and much stronger. Seriously? There are tens of thousands of homes that span 16, 18, 20 feet and have no supports on some beams. |
What size beam to span 14'
On 7/17/2012 5:00 PM, Ed Pawlowski wrote:
On Tue, 17 Jul 2012 13:30:23 -0500, wrote: I would not build anything with a 14 foot span. You'll get eventual sag in the middle no matter what you use, unless it's a steel girder. Use a center post. Seven feet is easy to span and much stronger. Seriously? There are tens of thousands of homes that span 16, 18, 20 feet and have no supports on some beams. Good point, a typical double garage door is what, 16-18'? |
What size beam to span 14'
On Tue, 17 Jul 2012 17:24:20 -0400, "Norm A. Brams"
wrote: On 7/17/2012 5:00 PM, Ed Pawlowski wrote: On Tue, 17 Jul 2012 13:30:23 -0500, wrote: I would not build anything with a 14 foot span. You'll get eventual sag in the middle no matter what you use, unless it's a steel girder. Use a center post. Seven feet is easy to span and much stronger. Seriously? There are tens of thousands of homes that span 16, 18, 20 feet and have no supports on some beams. Good point, a typical double garage door is what, 16-18'? Saw one, a concrete poured beam (lentil?) in a house that broke in the center and sagged over the garage door. Seemed odd to me as it was a first. The roof trusses dropped a few inches -- causing further roof damage. Strange to say the least. |
Quote:
Yes, I know I'll need a permit but there is no requirement for "architectural drawings" as long as the plans meet code. And there's no point in pursuing anything if the beam is going to be so goddamn big it doesn't blend with its surroundings! |
What size beam to span 14'
On Jul 17, 8:25*pm, 69roadrunner
wrote: 'Oren[_2_ Wrote: ;2893660']On Tue, 17 Jul 2012 10:06:10 -0500, "Doug" wrote: -- There are probably online beam load calculators that could answer the question. *But every place I know you would need a building permit to add a porch on to a house. *And here to get that building permit you need a drawing signed and stamped by a licensed architect. So, I'd start with finding out what it takes to get a building permit. *If it's like here, you'd be wasting your time figuring it out because the architect is going to do it anyway.- I guess you are right because everyone is saying the same thing. *I wanted to answer his question directly but just need more info but that will not address the legal aspects of building it.- The OP is in Canada. Yes, I know I'll need a permit but there is no requirement for "architectural drawings" as long as the plans meet code. And there's no point in pursuing anything if the beam is going to be so goddamn big it doesn't blend with its surroundings! -- 69roadrunner- Hide quoted text - - Show quoted text - Have you tried googling for online beam load calcualtors? I've seen them. I find it interesting that there are municipalities where they will approve something that is structural like this without an architect or engineer signing off on it. I mean I don't know that there is a specific code that just says for X porch you need Y beam. It would seem an architect or engineer would have to do the load analysis and make that decision. And it just seems odd that a local code official wants to be in the position of engineer of record for free for someone's building project. |
What size beam to span 14'
On Wed, 18 Jul 2012 05:13:46 -0700 (PDT), "
wrote: Have you tried googling for online beam load calcualtors? I've seen them. I find it interesting that there are municipalities where they will approve something that is structural like this without an architect or engineer signing off on it. I mean I don't know that there is a specific code that just says for X porch you need Y beam. It would seem an architect or engineer would have to do the load analysis and make that decision. And it just seems odd that a local code official wants to be in the position of engineer of record for free for someone's building project. In Nevada a home owner can act as their own contractor. I submitted a rough drawing with dimensions and the permit office gave me detailed drawings for footers, determined beam size, roof pitch, etc., based on having Spanish roofing tiles. Granted this was just a patio cover with some electrical work -- finished stucco. An architect in the permit reviewed what I "'wanted to build". Then issued the permit. Very helpful. A friend and I completed the work. He is experienced in construction more than I am (or will be) and was a great help. Saved plenty of money this way. |
What size beam to span 14'
I am planning to build a porch roof attached to the back of my house.
It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson www.anthonywatson.us www.mountain-software.com |
What size beam to span 14'
On Wed, 18 Jul 2012 14:51:54 +0000 (UTC), HerHusband
wrote: I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson www.anthonywatson.us www.mountain-software.com I can't say for sure without more info but I suspect your LL is too high. |
What size beam to span 14'
I can't say for sure without more info but I suspect
your [40psf] Live Load is too high. I wasn't sure where the OP was located, so I erred on the side of heavier snow loads. I've always used 30psf for live load calculations here in my area. In any case, I calculated it with the 30 psf and still came up with about the same size beam. When we built our house, I asked the truss company to design for 50 psf live loads, since we occasionally get heavy snow in the winter. Ironically, the only change this required in the trusses was slightly larger metal connecting plates. Kind of surprised me. Anthony Watson www.anthonywatson.us www.mountain-software.com |
What size beam to span 14'
On Wed, 18 Jul 2012 21:14:38 +0000 (UTC), HerHusband
wrote: I can't say for sure without more info but I suspect your [40psf] Live Load is too high. I wasn't sure where the OP was located, so I erred on the side of heavier snow loads. I've always used 30psf for live load calculations here in my area. In any case, I calculated it with the 30 psf and still came up with about the same size beam. When we built our house, I asked the truss company to design for 50 psf live loads, since we occasionally get heavy snow in the winter. Ironically, the only change this required in the trusses was slightly larger metal connecting plates. Kind of surprised me. Anthony Watson www.anthonywatson.us www.mountain-software.com grin. People often overlook the connections and seem to just worry about the beams / columns. Usually we try to make the connections stronger than the beam because if it fails at the connection, it can be sudden vs. the beam, usually bends before failing allowing people to get off. I'm a retired structural engineer so I speak from experience. Most of my experience is in steel / concrete but for a short part of my career I did wood (homes). Be careful tho when using your liveload because if you take full snowload with a full liveload (think what liveload is meant to include here), that's not likely in a real world sense. Sometimes in engineering we have to make educated guesses what we think the real loads will be over the life of a structure. Of course we would like to over design but depending on the structure, that can be too costly and most clients don't like that. Last, I commend you for thinking about loads when building your home... most people take this for granted. |
What size beam to span 14'
On Thu, 19 Jul 2012 01:09:30 +0000, 69roadrunner
wrote: 'Doug[_14_ Wrote: ;2894179']On Wed, 18 Jul 2012 14:51:54 +0000 (UTC), HerHusband wrote: -- I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs- Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson 'Anthony Watson of Camas, WA' (http://www.anthonywatson.us) 'Mountain Software Home - Recipe Software, Address Book Software, Calendar Software' (http://www.mountain-software.com)- I can't say for sure without more info but I suspect your LL is too high. Anthony, thanks for your detailed reply. All your assumptions are correct except for the load which, if I understand the truss specs correctly, is only 43.3 psf. Anyhow, I went to the city and they said any lumberyard could do the calc as well as supply engineered drawings (which appear to be all computer generated these days anyhow). The local yard I went to had them within minutes and recommended an engineered beam of 3" x 10". However, since I want to temporarily enclose this each winter I'm thinking I just may add some additional posts so there's something to attach the wall material to. However this is a lot more work (which I was trying to avoid with only 2 posts) since it involves cutting into an existing poured slab in order to install the sonotubes and poured piers. Nothin's ever easy !!!!!!!!! I hope they also checked for your deflection??? I don't know still what your PLF is but my hunch is your deflection is okay with a 10" beam depth. The width does little for the deflection. |
What size beam to span 14'
On Thu, 19 Jul 2012 00:23:17 -0500, "Doug"
wrote: On Thu, 19 Jul 2012 01:09:30 +0000, 69roadrunner wrote: 'Doug[_14_ Wrote: ;2894179']On Wed, 18 Jul 2012 14:51:54 +0000 (UTC), HerHusband wrote: -- I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs- Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson 'Anthony Watson of Camas, WA' (http://www.anthonywatson.us) 'Mountain Software Home - Recipe Software, Address Book Software, Calendar Software' (http://www.mountain-software.com)- I can't say for sure without more info but I suspect your LL is too high. Anthony, thanks for your detailed reply. All your assumptions are correct except for the load which, if I understand the truss specs correctly, is only 43.3 psf. Anyhow, I went to the city and they said any lumberyard could do the calc as well as supply engineered drawings (which appear to be all computer generated these days anyhow). The local yard I went to had them within minutes and recommended an engineered beam of 3" x 10". However, since I want to temporarily enclose this each winter I'm thinking I just may add some additional posts so there's something to attach the wall material to. However this is a lot more work (which I was trying to avoid with only 2 posts) since it involves cutting into an existing poured slab in order to install the sonotubes and poured piers. Nothin's ever easy !!!!!!!!! I hope they also checked for your deflection??? I don't know still what your PLF is but my hunch is your deflection is okay with a 10" beam depth. The width does little for the deflection. BTW, I was still assuming 14' length above. If you shorten it to say 7 feet, likely anything 2x6 or more will be fine for deflection. That said, do you really need an extra post for temporary walls? Maybe you do but I was hoping there was another way. I guess it depends on what the wall material is. |
Quote:
What's "PLF" ?? |
What size beam to span 14'
On Fri, 20 Jul 2012 00:11:47 +0000, 69roadrunner
wrote: 'Doug[_14_ Wrote: ;2894474']On Thu, 19 Jul 2012 00:23:17 -0500, "Doug" wrote: - On Thu, 19 Jul 2012 01:09:30 +0000, 69roadrunner wrote: - 'Doug[_14_ Wrote: - ;2894179']On Wed, 18 Jul 2012 14:51:54 +0000 (UTC), HerHusband wrote: -- I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs- Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson 'Anthony Watson of Camas, WA' ('Anthony Watson of Camas, WA' (http://www.anthonywatson.us)) 'Mountain Software Home - Recipe Software, Address Book Software, Calendar Software' (http://www.mountain-software.com)- I can't say for sure without more info but I suspect your LL is too high.- Anthony, thanks for your detailed reply. All your assumptions are correct except for the load which, if I understand the truss specs correctly, is only 43.3 psf. Anyhow, I went to the city and they said any lumberyard could do the calc as well as supply engineered drawings (which appear to be all computer generated these days anyhow). The local yard I went to had them within minutes and recommended an engineered beam of 3" x 10". However, since I want to temporarily enclose this each winter I'm thinking I just may add some additional posts so there's something to attach the wall material to. However this is a lot more work (which I was trying to avoid with only 2 posts) since it involves cutting into an existing poured slab in order to install the sonotubes and poured piers. Nothin's ever easy !!!!!!!!!- I hope they also checked for your deflection??? I don't know still what your PLF is but my hunch is your deflection is okay with a 10" beam depth. The width does little for the deflection. - BTW, I was still assuming 14' length above. If you shorten it to say 7 feet, likely anything 2x6 or more will be fine for deflection. That said, do you really need an extra post for temporary walls? Maybe you do but I was hoping there was another way. I guess it depends on what the wall material is. Well there's always a way - right ?!?!? Currently the "walls" are just some 1x3 spruce frames with plastic vapor barrier stapled to it. It just has to keep the snow out. But I'm thinking I'd like to enclose the lower half with a 3' cedar wall and then do something a little more rigid (but still temporary) around the top for winter. Posts every 7' wouldn't look all that bad and would give me something to build on. What's "PLF" ?? pounds per lineal foot ref: http://www.beamchek.com/loadbook/page5.html |
What size beam to span 14'
On Fri, 20 Jul 2012 00:11:47 +0000, 69roadrunner
wrote: 'Doug[_14_ Wrote: ;2894474']On Thu, 19 Jul 2012 00:23:17 -0500, "Doug" wrote: - On Thu, 19 Jul 2012 01:09:30 +0000, 69roadrunner wrote: - 'Doug[_14_ Wrote: - ;2894179']On Wed, 18 Jul 2012 14:51:54 +0000 (UTC), HerHusband wrote: -- I am planning to build a porch roof attached to the back of my house. It will have a trussed roof. The room will be 14' x 14'. I plan to support this with one end attached to the house and the other two corners supported by 6 X 6 pressure treated posts. What I need to know is what size each of the beams spanning the sides need to be to support the roof. There will be a 16" overhang on each side. Roof pitch is 4.5/12. Load is 43.3 psf. Length of one side of the truss is pretty close to 9' so the area of the roof (that each beam will support) is about 126 sq.ft.. Total load per beam of 5456 lbs- Just so I'm understanding correctly, you will have two beams running perpendicular to the house, with the trusses sitting on top parallel to the house? I assume you will be installing some kind of support posts on the house side of the wall as well, and not just relying on brackets or something? Your room is 14' wide with 16" overhang on each end for a total width of 16.7 feet. The length is 14' with a 16" overhang for a total length of 15.3 feet. 16.7 width x 15.3 length = 256.5 sq/ft Half of that load is carried by each beam, or approximately 128 sq/ft. I will assume a 20 psf dead load (weight of the building materials) and 40 psf live load (people on the roof, snow loads, etc.) for a total load of 60 psf. 60 psf x 128 sq/ft = 7680 pounds on each beam If you have a 6x6 post at the outer end, and the house end is supported inside the wall, your free span would be approximately 13.5 feet. But I'll err on the side of simplicity and say 14 feet. The size of the beam will vary depending on the wood species you use, but I'll assume Douglas Fir since that's common in my area. According the charts I have, you would need a 6x12 beam on each side to support 7680 pounds over a 14' span (assuming you want less than a 1/360 deflection). That's probably a lot larger than you were picturing. :) If you live in a warm climate without snow loads, you could probably get by with a 6x10 beam. However, if you add another post to reduce the span to 7', you would have 60psf x 64 sq/ft = 3840 pounds on each beam. In that case, a simple 4x8 beam would be more than adequate to carry the load. Of course, you will need to install some kind of diagonal bracing to prevent the whole structure from swaying sideways in winds or earth movements (lateral loads). Good luck, Anthony Watson 'Anthony Watson of Camas, WA' ('Anthony Watson of Camas, WA' (http://www.anthonywatson.us)) 'Mountain Software Home - Recipe Software, Address Book Software, Calendar Software' (http://www.mountain-software.com)- I can't say for sure without more info but I suspect your LL is too high.- Anthony, thanks for your detailed reply. All your assumptions are correct except for the load which, if I understand the truss specs correctly, is only 43.3 psf. Anyhow, I went to the city and they said any lumberyard could do the calc as well as supply engineered drawings (which appear to be all computer generated these days anyhow). The local yard I went to had them within minutes and recommended an engineered beam of 3" x 10". However, since I want to temporarily enclose this each winter I'm thinking I just may add some additional posts so there's something to attach the wall material to. However this is a lot more work (which I was trying to avoid with only 2 posts) since it involves cutting into an existing poured slab in order to install the sonotubes and poured piers. Nothin's ever easy !!!!!!!!!- I hope they also checked for your deflection??? I don't know still what your PLF is but my hunch is your deflection is okay with a 10" beam depth. The width does little for the deflection. - BTW, I was still assuming 14' length above. If you shorten it to say 7 feet, likely anything 2x6 or more will be fine for deflection. That said, do you really need an extra post for temporary walls? Maybe you do but I was hoping there was another way. I guess it depends on what the wall material is. Well there's always a way - right ?!?!? Currently the "walls" are just some 1x3 spruce frames with plastic vapor barrier stapled to it. It just has to keep the snow out. But I'm thinking I'd like to enclose the lower half with a 3' cedar wall and then do something a little more rigid (but still temporary) around the top for winter. Posts every 7' wouldn't look all that bad and would give me something to build on. What's "PLF" ?? Pounds per lineal foot ref: http://www.beamchek.com/loadbook/page5.html |
What size beam to span 14'
replying to trader4, Terry wrote:
Im building a pergola , how far can I span with a 2x8 treated beam. Needing to be 14. -- for full context, visit https://www.homeownershub.com/mainte...14-704987-.htm |
What size beam to span 14'
On 7/19/2018 6:44 PM, Terry wrote:
replying to trader4, Terry wrote: Im building a pergola , how far can I span with a 2x8 treated beam. Needing to be 14. Depends on the quality of the lumber and how much sag can you tolerate. |
What size beam to span 14'
On 7/19/2018 6:44 PM, Terry wrote:
replying to trader4, Terry wrote: Im building a pergola , how far can I span with a 2x8 treated beam. Needing to be 14. With no load you can go pretty far. It only has to support itself on a pergola. You will be good for 14' |
What size beam to span 14'
On Thursday, July 19, 2018 at 8:47:21 PM UTC-4, Ed Pawlowski wrote:
On 7/19/2018 6:44 PM, Terry wrote: replying to trader4, Terry wrote: Im building a pergola , how far can I span with a 2x8 treated beam. Needing to be 14. With no load you can go pretty far. It only has to support itself on a pergola. You will be good for 14' Yes and if he googles for floor loading calculator, joist calculator, beam calculator there are tools online that will give you the various options depending on the load, span, spacing, type of lumber |
What size beam to span 14'
On Thu, 19 Jul 2018 18:28:59 -0700 (PDT), trader_4
wrote: On Thursday, July 19, 2018 at 8:47:21 PM UTC-4, Ed Pawlowski wrote: On 7/19/2018 6:44 PM, Terry wrote: replying to trader4, Terry wrote: Im building a pergola , how far can I span with a 2x8 treated beam. Needing to be 14. With no load you can go pretty far. It only has to support itself on a pergola. You will be good for 14' Yes and if he googles for floor loading calculator, joist calculator, beam calculator there are tools online that will give you the various options depending on the load, span, spacing, type of lumber They spanned 12' with 2x8 hem/fir around 14" O/C in my house in Md and it never fell down. The design load was around 40 per sq/ft as I recall. Like Ed says, in a pergola where there is not much else up there it should be fine unless they strap the top with 1x4s to block the sun and you end up with a snow load. The one that was here in Florida when I moved in was spanning 13' with 2x6 SYP. |
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