Home |
Search |
Today's Posts |
|
Home Repair (alt.home.repair) For all homeowners and DIYers with many experienced tradesmen. Solve your toughest home fix-it problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Hello,
Next month I'm going to be partially resheathing and residing an exterior wall, so it will be open to the studs from the outside. The wall currently has cotton batt insulation, and I understand batt insulation can be leaky where it meets the framing. So I'm wondering what I can do from the exterior to seal up the wall cavity better, and I'm thinking foam. I'm considering a few options: 1) Discard the batts and foam the entire wall cavity. Probably too expensive given my climate (Berkeley, CA). 2) Spray the perimeter of each batt to seal it to the framing. Will this work? 3) Temporarily remove the batts and spray a thin layer of foam against the wallboard. The interior was recently remodeled, so the wallboard won't need replacing any time soon. Which of these is the way to go? In some areas I won't be removing the existing 1x4 plank sheathing, in which case option (3) isn't available. The plank sheathing has wide gaps everywhere, so I should still be able to access the wall cavity through it. Thanks, Wayne |
#2
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Wayne Whitney wrote:
Next month I'm going to be partially resheathing and residing an exterior wall, so it will be open to the studs from the outside. The wall currently has cotton batt insulation, and I understand batt insulation can be leaky where it meets the framing. So I'm wondering what I can do from the exterior to seal up the wall cavity better, and I'm thinking foam. I'm considering a few options: 1) Discard the batts and foam the entire wall cavity. Probably too expensive given my climate (Berkeley, CA). 2) Spray the perimeter of each batt to seal it to the framing... 3) Temporarily remove the batts and spray a thin layer of foam... Which of these is the way to go? Maybe 4) Staple black aluminum window screen into the south wall cavities to compress 3.5" R11 batts to 1.5" R6.2 batts and screw clear corrugated polycarbonate Dynaglas or Sun Tuf "solar siding" over the wall to make a thermosyphoning solar air heater which gains 0.9x1050 = 945 Btu and loses 6h(70-48.7)1ft^2/R1 = 128 Btu by day and 18h(70-48.7)1ft^2/R6.2 = 62 by night, for a net gain of 945-128-62 = 755 Btu/ft^2-day, vs the original wall which loses 24h(70-48.7)1ft^2/R11 = 46 Btu/ft^2 on an average January day in Berkeley. Nick |
#3
|
|||
|
|||
Insulating/Sealing Walls From Exterior
I would just leave the bats and add tyvek and, if your remodel would
allow for it, insulated foam board to the outside. Actually the foam boad goes under the tyvek. Some may say no need for tyvek if you use foam board. Anyway, the advice is free. |
#4
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Are you sure it is cotton and not cellulos loose fill that will fall out
if you take off the wood |
#5
|
|||
|
|||
Insulating/Sealing Walls From Exterior
On 2005-10-24, m Ransley wrote:
Are you sure it is cotton and not cellulos loose fill that will fall out if you take off the wood Yes, the insulation is cotton batts, I put them in when I remodeled the interior side. They are _so_ much nicer to work with than fiberglass batts. Speaking of cellulose fill (with a binder), does it create an effective air barrier? Should I consider pulling out the batts and spraying in cellulose? It's more economical than foam. Cheers, Wayne |
#6
|
|||
|
|||
Insulating/Sealing Walls From Exterior
On 2005-10-24, No wrote:
I would just leave the bats and add tyvek and, if your remodel would allow for it, insulated foam board to the outside. Well, I fall on the felt side of the tyvek vs felt argument, so I'll be using 30 lb felt. The siding is cedar shingles, and at least some cedar shingle manufacturers recommend felt instead of tyvek. I may use cedar breather (1/4" thick mesh) under the shingles as a mini rain screen. As to the foam board, is there any value to 1/4" foam board? Would it be an effective air barrier, and what would I use to tape the seams? I don't want to make the wall any thicker than it is, as I don't want to mess with the frieze board and molding details at the top of the wall. So I'll be leaving 2-3' of the 7/8" plank sheathing at the top of the wall, and there I'll just have to seal the gaps in the sheathing with spray foam. But the new sheathing will be 1/2" or 3/8" CDX, and I'll have 3/8" or 1/2" of thickness to make up. So I could use 1/4" foam board and 1/4" cedar breather. Cheers, Wayne |
#7
|
|||
|
|||
Insulating/Sealing Walls From Exterior
|
#8
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Wayne Whitney wrote:
On 2005-10-24, m Ransley wrote: Are you sure it is cotton and not cellulos loose fill that will fall out if you take off the wood Yes, the insulation is cotton batts, I put them in when I remodeled the interior side. I would definitely get that out of there and replace it with a modern conventional insulation, it will work better and be far less to cause vermin or other problems. -- Joseph Meehan Dia duit |
#9
|
|||
|
|||
Insulating/Sealing Walls From Exterior
On 2005-10-24, Joseph Meehan wrote:
Wayne Whitney wrote: Yes, the insulation is cotton batts, I put them in when I remodeled the interior side. I would definitely get that out of there and replace it with a modern conventional insulation, it will work better and be far less to cause vermin or other problems. Umm, these cotton batts are a "modern conventional insulation", they are treated with borates to provide fire and vermin resistance. See, e.g., http://www.bondedlogic.com/. Cotton batts are a much nicer alternative to fiberglass batts, but more expensive. Anyway, the original question was about batts insulation in general, and sealing the batt/framing interface. Cheers, Wayne |
#10
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Wayne Whitney wrote:
On 2005-10-24, Joseph Meehan wrote: Wayne Whitney wrote: Yes, the insulation is cotton batts, I put them in when I remodeled the interior side. I would definitely get that out of there and replace it with a modern conventional insulation, it will work better and be far less to cause vermin or other problems. Umm, these cotton batts are a "modern conventional insulation", they are treated with borates to provide fire and vermin resistance. See, e.g., http://www.bondedlogic.com/. Cotton batts are a much nicer alternative to fiberglass batts, but more expensive. Anyway, the original question was about batts insulation in general, and sealing the batt/framing interface. Cheers, Wayne Maybe I need to get up to speed. I have not seen any for many years and it was old then. I did not even know they were selling the stuff. It sounds like they have done the same kind of work on it as the cellulose stuff. -- Joseph Meehan Dia duit |
#11
|
|||
|
|||
Insulating/Sealing Walls From Exterior
What is the R value of ultra touch, that web site did not display it.
|
#12
|
|||
|
|||
Insulating/Sealing Walls From Exterior
On 2005-10-24, m Ransley wrote:
What is the R value of ultra touch, that web site did not display it. Yah, their site http://www.bondedlogic.com is a bit unclear, you have to go to "Technical Library" to get the specs. They make R-13 at 3.5" deep and R-19 at 5.5" deep, in 16" and 24" widths. Wayne |
#13
|
|||
|
|||
Insulating/Sealing Walls From Exterior
Blue jeans have a good R value, I have cedar, I removed it, ran 2" of R
7.2" foamboard for R 14.4, plus foamed the cavity for R 32. I put 3/8 Osb then tyvek, only to protect the Osb. But Im zone 5 to - 20f. I dont know your extremes, zone, but im sure cooling is the issue. 1/4" foamboard of blue or pink is apx R 1.25, foifaced foamboard apx R 1.8R. Not very much for all that extra work, then you need Osb. If you want to foam add more the labor is the same, tyvek alone will help alot without more insulation. There is R 7 foam blown in but it outgasses, and R5 that does not outgas. 1" of 7.2R per inch foamboard would help alot, but your windows and trim will be recessed, I put in new windows and doors while doing this, upped attic insulation and new Hvac, my utility bills are down 75% |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
removing cobwebs from exterior walls of house? | Home Repair | |||
Preparing exterior walls for painting | UK diy | |||
Best possible insulation for 2x4 walls? | Home Ownership | |||
indoor walls: spray paint or roll paint with rollers? | Home Repair |