Old Cottage with beadboard paneling and no insulation
We have an old 1919 cottage with 3/4 beadboard paneling on many of the interior walls, all of the ceilings and they were never insulated. The exterior was badly decomposing stucco with asbestos that we had removed and we will restucco the house with real stucco. Our problem is that we cannot figure out how to insulate from the outside in, as removing the beadboard is not an option due to splintering.
We would like to foam from the exterior except that we have to put some sort of barrier in the cavities before foaming as the foam will push out into every available nook and cranny. Also the bids we have received to foam the entire house have been $25-30k, with the walls being about $11k. Very pricey and the payback is never. Another firm wanted to have the plywood put on the exterior, drill holes and then put foam into the cavities which seemed like a lot of redundant work and expensive.
As we cannot afford to foam the entire house, our next best option is to install batts with the paper facing the interior beadboard but we would not be able to staple the flanges to get a good seal and fear air leakage and lack of a proper vapor retarder. We would then continue with normal wall construction; plywood, house wrap, stucco. This doesn’t seem correct but we have run out of answers.
Any thoughts?
Replies
This might be a good place for wet-blown cellulose. Goes on a bit like foam.
The house is located in a year round very high humidity
area next to Lake Michigan so no one has recommended using wet blown cellulose. Especially with beadboard which is tongue and grooved but 100 years old so it is quite leaky and is easily penetrated by air, dirt and humidity.
Thanks for your input.
If you're really gonna
give the place a complete do-over, the best bet is to remove the stucco, remove whatever sheathing there is, install insulation, re-sheathe it, install a WRB, and re-install the stucco. I would consider installing rigid foam in the stud bays instead of fluffy insulation, but there are ways to make batts stick, or use wet cells as Dan suggests.
The stucco has been totally removed and as it was
mounted on wood lathe, we are down to the open studs, with the back of the beadboard showing. Quite a bit of daylight can be seen when viewed from the inside! We did think about rigid foam but worried about a good seal on the edges next to the studs. Someone else suggested that we could foam the edges to make it airtight. We hope that our insulation contractor has some ideas but it is always best to know as much as one can about the process.
Thanks for your input.
Cut the foam
to stud bay minus 1/2", and foam the edges on both sides. You need a pro foam gun to do this nicely, don't bother with the cans with straws. I think in your case I'd use 3" foil polyiso, push it in tight to the beadboard, and then put the sheathing on with an airspace to the foam. If you have seams in the foam, tape the pieces together with whatever tape the manufacturer says.
Bead Board Not an Air Barrier
Bead board panelling will be air permeable between every board so an air barrier will need to be well detailed elsewhere. House wrap and stucco done properly can form an air barrier on the walls but the ceiling will need to be air sealed too. Paper facing on batt insulation won't be an air barrier even under the most ideal conditions with perfect workmanship.