What I thought was a kitchen addition (adding 60 square feet, and allowing the installation of a dishwasher and pantry area), was an original back porch enclosed to make it living space. On the inside it’s easy to tell where the porch starts because there is a sharp downward slope there. So, the porch is slumping off the house. And apparently not for the first time.
The previous owner left me a number of house-related receipts and one of them was for work done to raise the porch. The receipt shows that in 1999 the contractor installed pilings and a beam, and ‘refreshed’ the skirting and floor. For that work the previous owner paid $1350.
I took a look under the porch and saw what appears to be open ground covered with cellulose insulation to within 8 inches of the top of the crawl space. I also see scads of mouse droppings and bugs and spiders.
And also, there’s a gap up the side of the house where the porch is pulling away. Since my goal is to seal and insulate the house properly, I’m not sure what to do. Is it biting off too much to chew if I get under the porch to try and fix it? Maybe if there are pilings there, all that needs to be done is to raise the beam again, with a floor jack. That begs the question of why the beams would have dropped again after just 18 years, but that would be for a professional to answer. Maybe I can get another in for $1300, like the good old days.
I read that to get proper insulation for a warm kitchen addition, I need to treat the space underneath as ‘conditioned’ space, like I would a basement – insulated on the perimeter (including the ground) and not on the floor.
Alternatively, I could use rigid foil faced insulation that is attached to the bottom of the floor joists, as long as it is sealed completely (airtight). I’m not sure I can do that in the tight space under the porch, but it’s something I could try myself.
And another alternative is spray foam – I’ve read that it has to be high density foam – at least 2 lb/ft3—and at least 3 inches thick or thicker, over the joists and subfloor (completely encasing the floor system). This is something I’d have to hire out.
Or maybe I should pull the porch off altogether and do without that 60 square feet. It’s my plan to redo the kitchen anyway, maybe just sooner rather than later? Of course, that means the new-ish deck would have to come off too, as it’s anchored to the kitchen/porch wall. It’s never easy, is it?
I’m leaning toward jacking up the floor again and spray-foaming the heck out of it, and then the mice can party like it’s 1999 all they like under the porch and it won’t bother me one bit.