Wall Insulation in Texas

[5thGenTexan (WavyGlass)]

The house I will be buying from the estate of my grandmother has no insulation in the walls. Ok, except for the portions where my grandparents had insulation blown in during the late 70s. Those are also the places where paint will not stay on the house.

A bit of information on the wall structure that I have, and that seems to be common in Texas.

Outside is wood siding over studs with nothing between the siding and the studs.

Inside wall is 1x6 shiplap over the studs. Originally there was a cheesecloth material tacked to the shiplap and wallpaper was applied over the cheesecloth.

My grandmother removed most of the wallpaper and cheesecloth and put up paneling that she then stenciled herself. My wife does not care for the paneling that my grandmother put up, nor the way its painted. Over time we will probably end up taking it all down back to the 1x6 shiplap.

Now then, since there is nothing between the siding and the studs I am thinking that blowing in any type of insulation is a bad idea. There is nothing to keep any rain that might get behind the siding from wetting the insulation. The only solution would be to remove ALL the siding and start over. I don't think that is going to happen.

What if I put something like Tyvek on the inside over the 1x6 shiplap. House can still breathe like it needs to, but it will be something to stop the wind from blowing through.

[Don M]

That might work; I assume you would then sheetrock over the Tyvek? I would be more worried about what is happening in the walls where the insulation was blown in. If paint is peeling then there is probably moisture trapped in the insulation which also maybe rotting the structure from the inside out.

[Sashguy]

I work on homes in Houston built prior to 1940 and see this on occasion. Due to the lack of moisture barrier, the insulation gets moisture laden and slides into a muddy mess at the bottom of the wall. Typically, the lower 2.5' starts rejecting paint due to the moisture, and rot sets in. My fix is to remove a couple rows of siding at the bottom and scrape it out. This is not a major task in balloon frame homes due to the lack of fire breaks. Also be aware of the restriction above the windows and doors, as the insulation can get trapped there also. It may be necessary to pull the upper trim panel to allow access.
I do not use the old school method of driving the nail heads through the siding for removal. I pry the siding out enough to allow room to insert a saws all metal cutting blade between the siding and studs and cut the nail shanks. Of course, in doing this, you must be mindful of the location of the electrical wires. I allow it to dry out, brush on rot treatment and replace the siding.

[rncx (WavyGlass)]

Hey 5thGenTexan, I live over in Allen. We have another person on here from the Richardson/Garland area too. I keep my little old airplane at your airport over in McKinney.

You're right, blowing insulation in is a bad idea because it'll trap water. I know it's not overly wet in North TX, but it only takes one leak to start growing mold in the wall...

Is the structure strong enough to hold another layer of shiplap on the outside? Honestly, that would be the best course of action, followed by new siding on the outside.

[phil]

what would happen if you put sheets of closed cell insulation 1 or 2 inches thick on the inside of the shiplap? strap the studs, at ;least every second one, so you have something to screw your drywall to, and left the wall cavities open? any window frames and sills would have to be made wider ( extend them) which isn't particularly nice but than you wouldn't have to disturb your siding. the room would be an inch or two smaller but that might not be such an issue. the closed cell foam might work as a vapor barrier or you could add one. Not sure if that is a good fix or not but is it an option?
Phil

[BigBill (WavyGlass)]

We have the same type of walls in our old farm house in East Texas. Eventually we are replacing the siding due to rot but in the meantime what we did was to caulk any cracks in the interior shiplap, then covered it with a plastic vapor barrier then 3/8" sheetrock, textured the walls and painted. It came out nice looking and a whole lot warmer. There is no insulation in the walls now, but i did have to remove the bottom couple layers to repair the mud board in a few places. I followed the same procedure as Sashguy explained. We are replacing the siding by first putting up 1/2" OSB, covering that with tyvek, then the siding. Once that is done we'll blow in the insulation.