Fixing Unwanted Thermal Transfer
 

I live in a 2 story 1800 square foot house, built in 1998. It's exterior walls are constructed with 2 by 4 wood studs. The walls on the west side are 3 to 4 degrees warmer than interior walls in the afternoon. Thats on the first floor. Second floor is 5 or more.

What has been most effective in reducing the transfer of heat/cold? Also, how about cost effective?

AC, you mentioned it somewhere, but it eludes me.

Geo

We had a lot of solar heat gain in our Den from the west side windows.
It's been reduced by about 85% using a couple Solar Screens.
http://ecorenovator.org/forum/renova...n-project.html
When the sun was allowed to shine into that area, it heated up the interior,
and of course the interior walls will pick up some of that heat (re-radiated).


I wonder if you have siding on the house?
I have found that vinyl siding with foam insulation installed under it, works pretty well.
I think ours is about 1/3" thick with aluminum foil to reflect radiant heat.

[QUOTE=Xringer;23487]
I wonder if you have siding on the house?
QUOTE]

Its T1-11 wood siding. The walls are carrying lots of heat through them and radiating it into the house. I am seriously thinking of having the walls filled with the spray foam, but then again, how much heat transfer will the wood studs pickup and transfer?

I have thought of installing a thin wall on the interior of the house to seperate the two, but it would sure be nice to know that the heat/cold is staying put on the exterior.

If spray foam is installed in the exterior walls, then you shouldn't have to worry about moisture building up in the walls, right? Then why not install a waterproof butyl rubber membrane wall sheeting on the exterior?

I know that in cold climates, covering an entire wall section with waterproof membrane will create a cold-side vapor barrier, potentially leading to serious moisture problems and wood decay within the wall cavity. But with the spray foam in place, what would happen? Would the wood still rot from vapor issues?

I've seen some T1-11 siding on a few sheds around here, but never knew what it called. Had to look it up.
All T1-11 is NOT Created Equal - YouTube

My guess is, you have sheet-rock, then fiberglass battens and then the T1-11.?.

If that's the case, then adding on an outside layer vinyl siding with insulation under it, would be easiest to do.

A light colored siding would be a bit cooler in the summer..
Shop Georgia-Pacific 10-in x 10-ft white Traditional Vinyl Siding at Lowes.com

People put vapor impermeable materials on the sheathing of their houses all the time. You just need to make sure the wall can dry to the inside. You can spray foam on the T1-11 but the cost effectiveness may not make sense. That stuff is by far the most expensive of the common insulations and, I hate to say it, is easily botched. Do you have existing wall insulation? You can assume somewhere around 20%, or maybe a little less, of your wall is framing lumber.

Its hard to know which the best solution would be to insulate an exsisting home. The performance of the system vs. the cost and return on investment. The words out-sulate are now being used in the high perfomance net-zero type homes. This out-sulate is a insulating material such as foam board wrapping the entire house on the exterior. With this system typically difficult areas to insulate like the band just above the foundation is addressed. To try to insulate and prevent heat transfer thru the floor joist is very difficult for the traditional methods. Here in Canada's harsh climate its proving to be quite effective. The foam boards are easy to install over the studs and sealed with tape. This makes the home very air-tight and the heat-transfer though the studs a non issue. You may consider yourself lucky in one sense having only siding to replace after the out-sulate as if you had brick siding would make it prohibitive. The materials are inexpensive and can be DIY. The siding may have to be replaced by a professional because of the extra details around the windows and doors.

I had been part of the construction of a huge home here in Ontario and the owner/builder went the extra mile with two layers (3" total) of foam board over his 2x6 stud wall (R20) His heating bill is stunningly in-expensive for a home that size.

Randen