We met with our architect yesterday and signed the paperwork so it’s official. We talked about the plans and started working some things out about how we’re going to renovate and live here at the same time. In an earlier post I mentioned that we’d decided to go with spray foam insulation instead of building a double wall so that we don’t lose square footage and still get a high R value. We’re also anticipating having to re-sheath the exterior, meaning we’d pull off all of the existing wood planks and put on new plywood, because they’re 115 years old and are probably water damaged and rotted. We don’t know this for certain, but we’re assuming the worst, given the condition of the rest of the house and the parts of the planks we can see, and we don’t want to assume it’s in good shape and then be surprised.

According to our architect, normally the exterior is done first.  We would replace all of the planks with plywood and then spray foam onto the new sheathing. It means everything seals nice and tight, plus we can install the new windows and flash them properly. However, it raises some problems. In order to re-sheath and re-side the exterior, some other things need to happen first. We’re planning to remove the second floor bump out, eliminate and move some windows on both floors, add sliding doors on both floors where the deck will eventually be, as well as remove the enclosed back porch and put on a front porch. We’d rather not make a mess of the second floor while we’re living in it, but even allowing for that we need to keep the back porch because it will have the only set of stairs once we’ve ripped out the front stairs, and we can’t replace the sheathing and siding while there’s a porch in the way.

That leads us to think it would be better to gut and finish the first floor first, followed by the second floor, and then redo the exterior. That’s been our intention all along since it gets us into the first floor sooner and pushes back the cost of re-siding for a few years. Unfortunately, if we spray foam first it will bond to the existing planks, making it impossible to remove them and re-sheath later. I spent a lot of time thinking about the logistics of trying to do the exterior first. Maybe we could replace the sheathing and siding one floor at a time? That doesn’t address the problem with the back porch. Finally I gave up and went back to the original plan.

When we demo the interior walls we’ll be able to inspect the planks and see what shape they’re in. If they don’t need to be replaced, then we don’t have anything to worry about and we can spray foam the interior. If they do need to be replaced,  we’ll put 1″ thick sheets of rigid foam insulation into the wall cavities against the planks, and then spray foam over them. That way the spray foam will bond to the rigid insulation instead of the planks, so we can still replace them later. It may not be a perfect solution, but it’s the best one we’ve come up with.