120 year old siding needs replacement
 

I'm currently restoring an old 120 house, which amazingly still has it's original siding. It is old growth fir (true) 1" x 6" ship lap siding. But it has deteriorated to the point of needing replacement (and not just patching).

My problem is that there is that:

1. There is no sheeting on the house (meaning the siding is attached directly to the studs)
2. There is 4 to 5 inches of sprayed on (closed cell) expanding foam directly on the interior side of the siding. The layers are siding, foam, air pocket and 1/2" drywall.

My question is: Whats the best way to remove the siding (along with the foam) without disturbing the interior drywall. And after it's been removed, the best way to re-valor barrier and re-insulate the wall (in between the new sheeting and the interior drywall)? Would spray foam work again, but attached to the interior drywall?



Thanks!


(This is my first post btw.)

Why do you feel you have to remove the foam that's there now?

Hey welcome to the site. Like joe said if you can leave the foam there, good. If not using foam again will be good as it is a vapour barrier too.

It's really too bad that you can't patch the old siding in places and then just go over it with a new siding. But if it has to go, and you can't leave the old foam in place, then yes you can spray new foam insulation. But be prepared for the cost!
There are some alternatives you may want to consider.

The foam is literally glued to the back side of the decayed siding. When the foam is strayed onto wood, it gets embedded into the wood fibers. When I remove the siding, most of the foam will come with it.

That was my thought when I first bought the house; to just patch the siding. But I've found out, by taking various samples around the house, that the siding has the same weight and consistency as balsa wood - very bridle and light weight. So, it will have to be replaced in the next or so (it's starting to leak a little).

What other alternatives do you suggest?

I'd tear the siding off from the outside, remove then remove the foam. Re-insulate with fiberglass, nail up some sheathing, install a vapor barrier and then hand some vinyl siding.
You may run into a problem where the sheathing puts you out further than the window trim so the window trim would have to extended.

I was hoping to avoid vinyl siding, since the house is a 'folk' Queen Anne house. There are a lot of angles and details that would even challenge vinyl siding...

I would cut out any rot that you have, replace the dammaged foam and replace with new wood, house wrap and install siding. Have you looked at Hardy?

Some bad advice here....never put a vapor barrier on the exterior of a house...never!

After you remove the siding and foam, the best advice is to re-insulate with foam as it is a vapor barrier also. If you use fiberglass, you must put the vapor barrier to the INSIDE of the home first, then insulate.

Then the sheathing can go on and then the house wrap. Hardie plank or shingles is a cementitious product and is an excellent choice for a finish siding. It has a slightly thinner profile and may not project out too far beyond window frames, etc.