Hey gang, it’s been a while. We are renovating the kitchen in our 1916 bungalow and I’m thinking about adding insulation to the exterior wall (north wall) before I patch and skim coat the plaster walls. There is currently no insulation in the extrerior walls of our house.
Are there any downsides to adding blown-in to an old house? My concern is moisture.
Also, which insulator is the better choice, fiberglass or cellulose?
I’d appreciate any advice you can offer.
Replies
BE sure there isn't any knob and tube in the walls - covering it with thermal insul is a fire hazard.
You might wander around the old house journal site for experienced homeowner input.
Good point about the K&T
Good point about the K&T wire.
Insulating an old building can have huge impacts on thermal and moisture performance. You may have old windows and doors, no felt or other WRB, no flashing, etc., and while moisture may currently be leaking into your walls in places, it may also be drying out quite easily. Fill the same walls with insulation and moisture stays a LOT longer. Insulating could have serious unintended consequences.
There's a ~100 y/o church here, it has shiplap siding over the studs with no felt at all. Some years ago they had someone blow in insulation, and the next winter they started finding moisture stains around windows where none had shown before. The remedy is to reside he building and install flashings everywhere needed. Ouch.
That is exactly what I was worried about. There's no felt on this house and with 38 old windows and 4 old exterior doors on an 1800 Sq Ft home, there's not a whole lot of wall to insulate. Although there is no knob & tube to worry about (I had it rewired), I think I'll pass on insulating for the time being.
Eventually we're going to strip the old siding off and put up new cedar, at which time I can insulate, flash, housewrap,etc.
Thanks to you both for the expert advice.
Might want to post your question over at Breaktime Classic
If you have entire walls open from the inside there may be techniques to consider, but if you know you're going to reside down the road I'd just deal with it then. IMO the idea of retro-insulating all the world's houses per the current administration is madness, it'll just lead to huge amounts of building damage over the long run. Strip & reside is what's going to be needed to make most of them last.
Check over at Old House Journal- a lot of good exprience with these issues there