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Insulation Question

I am restoring a 1850s farm house in the Atlanta, Ga area. The existing exterior walls are old clapboard outside and old wood planking inside. No insulation and the outer clapboards are nowhere near tight; in places where the interior planking is gone or damaged you can see lots of light coming in through the outer wall.

Problem is I would like to insulate without tearing off either the exterior clapboards or interior wallboards, both are historic and for the most part in good structural shape. One idea I have been investigating is the use of injected foam. However I have been warned that the lack of ventilation will cause the old clapboards to rot.

I am also considering spray foam in the attic and under the floors. Again as much to seal all the cracks and openings as to insulate.

Any advice would be appreciated.

Re: Insulation Question

I have the same concerns, and have posted about it an another thread (Should we use Spray Foam in an 1880 Victorian). I dont knwo if spray foam will cause a ventilation problem for and old house's wood siding.

Re: Insulation Question

Quality has no easy answer.

Spray foam is the easy answer and it's what most people do who sell that old home. Although anyone who buys it won’t be pleased.

I'd pull off the wall on one side or the other and insulate it properly. Afer a few hundred years of experience doing it improperly, that's how it's done in Europe; where many homes are far older than yours.

If you plan on living in that home for any length of time, the time spent doing it properly will seem like nothing. Foam insulation doesn't allow the framing members of your home to breath. Foam accepts no moisture so it all stays in the framing members and they rot. Don't do it.

Re: Insulation Question

Injection foam will work in your home, it is 60% closed and 40% open cell so it will breath. But if you say that you can see daylight out side, i think that you may want to conserder tightning up the siding. it sounds like you have some bad boards or rot allready happing. if you are that worried about rot it needs to be addressed with a vapor barrier on the out sides of the studs, if water is comming in, that will be a problem with what ever you do.

Also there is nothing wrong will spray foam, it is the best thing that you can get right now, that would be an option if you could remove the siding, spray, then reinstall with you original boards, it may sound like alot of work, but the spray foam will pay for it's self in roughly 4-10 years depending on the size of your home. injection would pay off in 3-7 years depending on size.

Good luck

jaros bros.
Re: Insulation Question

Yes, there is another thread going on right now with this same question. Everyone has been giving their advice, and most of it is conflicting. Problem is that people are trying to convert old building assemblies into new building assemblies and in the process they are trying to forgo necessary changes. If you don't do certain things you are going to cause some serious problems. Older houses leak a lot so you don't get the buildup of interior moisture like you do in a new one. When you go to tighten up an old assembly, you now have to deal with where this moisture is going to go...that goes for the interior as well as the exterior. If you don't address this issue you will have rotten siding and mold growing in no time at all. Newer assemblies call for vapor barriers, rainscreens, insulation types, etc. There are a number of factors to consider such as climate and exterior cladding. You can't just say this or that, you have to take everything into consideration.

Josh Jaros

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