Redoing wall insulation for wind
We are going to be putting in new windows on one wall of our living room. This wall bears the brunt of the wind we get so I want to do something to minimize wind intrusion.
I am going to be tearing off the interior wall which is 3/4″ knotty pine paneling that I will refinish and put back up. The whole living room used to be pine and I feel obligated to keep the one wall for sentimental reasons.
I plan on redoing the insulation and I’m thinking of putting in 1/2″ xps or some-such against the outside wall before the fiberglass batts. I guess my concern is if this will cause any sort of vapor barrier issues.
The house is outside Seattle in a maritime climate. Construction is cedar shingles, felt, shiplap boards, studs/insulation circa 1949, paneling.
Thanks for any input
Bob
Replies
It depends on where you live. If you live in a heating climate I wouldn't put the xps on before the fiberglass.. you will be creating a plane for moisture to condense on, as vapor travels from the warmer inside to the cooler outside it will be trapped and condense on this surface. As for air infiltration, caulk/foam any gaps and cracks you can and I would use dense pack cellulose over fiberglass for it ability to stop air infiltration. In your situation if you must use xps and fiberglass I would put the xps on the inside of the fiberglass.
I'm pretty open as to what to use for insulation, I just want to block wind intrusion. It comes in pretty cold and relentless off the water during the winter. In our area we have fairly mild weather year-round but have to heat during the colder months.
Vancouver (Canada) calling ....
Try this.
Remove everything down to the studs.
I used mineral wool insulation (Roxol, here) for my insulation, rather than fiberglass. Preference, as they are about the same price.
I cut 2" strips of 5/8" solid pink polystyrene and glued/nailed them to the studs for a thermal break. Then, I'm putting on a 6 mil vapor barrier, and the drywall will go on that.
Make sure there are no cuts/tears in the poly vapor barrier - drywallers will slash like crazy to get the boards on flat & good.
You won't believe the difference.Quality repairs for your home.
AaronR ConstructionVancouver, Canada
I cut 2" strips of 5/8" solid pink polystyrene and glued/nailed them to the studs for a thermal break. Then, I'm putting on a 6 mil vapor barrier, and the drywall will go on that.
Why not continous 1" XPS on the inside of the wall and eliminate the poly. This will not only offer a better thermal break, but also additional R-value to the insulation cavities and serve as an air/vapor barrier.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Force of habit.
I do it this way because XPS here is more expensive and just as labourious. Also, with old walls, as you know, putting rigid insulation on the back helps the drywall folks get their part of the job done faster.Quality repairs for your home.
AaronR ConstructionVancouver, Canada
The best thing for any air passage is foamed insulation. It stops any and all air from coming through. Drawback is that it's rather expensive. Another good quality though is that it greatly improves the structural integrity of any wall. I would call a professional insulator and get a quote.
Next best thing is to cut rigid insulation to loosely fit into the stud bays, then foam all the seams between the wood and pieces of foam. What you can do to get the R-value is to install unfaced R-13 first, then use maybe 1" or even 1/2" rigid. We have used this method many times and it really is superior.
I like the idea that Aaron brought up about creating a thermal break on the studs. I may try that at some point.
I have a crawlspace that I am going to insulate this way probably this summer.
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Thank you, I really should look into the foam thing. Another post here pointed to diy options which are kind of intriguing. I will look into having someone else do it. It sounds like it often doesn't cost much more to have it done than it would cost me to just buy the supplies. The issue is: if someone would come out here to do just the one wall.
I would look into having spray foam installed. I know a couple of subs here in WA and there are doubtless others. Corbond would probably be the right foam if you only have 2x4s. With wood paneling on the interior you have very poor air sealing.
My house has the same problems: cedar shingles over felt over board sheathing, 2x4 walls with poorly blown cellulose, and 1x4 t&g paneling on the interior. I am trying to summon forth the energy to strip all of the paneling off, replace the insulation with foam, and then install drywall. Ugh.
What, you're not putting back the paneling? It IS kind of dated. Over the years, as I have done various of the walls, I have taken out the paneling as I went along. For some reason I feel compelled to keep a wall of it for old times sake, in memory of that vacation cabin look we came upon 6 years ago when we first saw this house on Agate Pass outside of Suquamish.Actually the guy who's father built this house came by a few months ago with pictures. One of our favorite features of this place is a giant spreading 50 year old Catalpa tree next to the house. He gave us a picture of the house showing the tree when it was a little twig. Anyway when he and his sister were little kids they used to play a game involving the paneling and the first thing he did was walk over to the wall and started "picking berries" which involved touching all the knots as fast as you can. Memories...
Our paneling has suffered a hideous fate--there is wallpaper over it, and skip trowel drywall texture over that. Plus, it's a terrible fire hazard, and as I said first it's a terrible air seal as well. If you foam your wall cavities then the air seal issue is moot, but the fire hazard is still real. Actually, if you foam the walls you are probably required by code to cover the foam with drywall. You could then reinstall the wood over that. Check with your inspector.
Hmm, I hadn't thought of the fire hazard aspect, I'll have to think on that.
thanks
Do I hear an invitation to a long holiday weekend coming up.......
Got Kosher food for me there and genuine Czech beer?
Quality repairs for your home.AaronR Construction
Vancouver, Canada
Edited 3/30/2008 2:36 am by AaronRosenthal
Realistically it won't happen this year, unless work stops dead AND I feel comfortable enough to borrow money. Just gutting all the paneling and blown in will take a couple of guys a couple of days, plus another guy to haul to the dumpster. Then I need to do some wiring and plumbing. Then hire the insulator. Then hire the rocker. Then hire the painter. Then get new kitchen cabs and counters, and a new floor. Gee, I think I just talked myself out of it.
But you folks are welcome anytime. What I DO have is some energy left to finish the space above the shop, which is a 500SF studio room with a full bath. Brand new. Needs tile and wood flooring. We're plugging away on that.
Nothing stops wind/air infiltration like spray foam. It gets into the crevices and fills them. As for exactly what type in the Seattle area, I have no idea.
BHosch
You didn't mention if the knotty pine was the only interior covering.
Whatever insulation method you choose, make sure you air seal the wall with XPS like Riversong mentioned, or the poly and then sheetrock. Then put on your knotty pine.
I would but XPS over the studs and blow the walls with cellulose, SR and knotty pine.
Making sure to get the XPS sealed tightly.
Rich
Thanks for the suggestions. Now by blow the wall with cellulose do you mean rent one of those blowers with some bags of the shredded paper stuff? I guess I would drill some holes in the xps etc.The knotty pine is in fact the only interior covering so the whole wall is like a sieve at this point. Cedar shake/shiplap/thin paper covered cellulose batt insulation/knotty pine boards. Is the sheet rock layer you mentioned for fire protection or other?This is good, I wish I had put more attention into the other walls which are just the usual home center fiberglass batts in a 3-1/2 wall cavity with sheetrock.Thanks again
BHorsch
Fiberglass is a very poor air sealer, that is why they use it for furnace filters. The bottom of stud cavities will look like that sometimes from all the air flow at the plate.
Dense pak cellulose will seal the wall much better. Spray foam is the best air sealer. Yes you would rent a Force 2 machine and run the air pressure at full and the material gate you would close to only allow about 30 % of the gate open. Alot of air pressure and a little cellulose.
The purpose of the 1" XPS is to add R5 to the whole wall and break the thermal bridge at the studs. The XPS can also serve as the air barrier/vapor barrier if you seal the seams and the edges. Tyvek tape the seals and leave a 3/8 gap at the edges that you hit with Great stuff foam.
The sheetrock is needed to protect the foam from fire. Foam will give off poisionous gas when exposed to fire.
The sheetrock is also a good air barrier if you tape the joints (called fire taping) and if you seal the bottom to the plate with caulk.
If you are going to not use XPS then you will need to use Insul-Mesh stapled to the studs. Search Mooney wall and you will see some pictures of the procedure. If you do not use XPS then you may want to use a polyethlene vapor barrier. (4 mil plastic).
The only problem with XPS/ then sheetrock/ then knotty pine is you have to nail 2 1/4" before you hit studs.
You may have to compromise. Or bit the bullet and hire the wall foamed, sheetrock and then install knotty pine.
Hope we haven't confused you.
Rich
In Seattle you're probably safe. You could be safer by putting up housewrap instead. Assuming no firestops run a continuous sheet of housewrap horizontally, stapling it into the corners and wrapping around the fronts of the studs.