Home>Discussions>INSULATION & HVAC>Insulating concerns in a 100 year old house
5 posts / 0 new
Last post
rupperthawes
Insulating concerns in a 100 year old house

We just bought a 100+ year old house and have started the renovations. We have heard there are some concerns about insulating an old house too tightly. What is your advice about insulating an old victorian/transitional house. Could we use spray foam insulation to seal the roof after the new roof is put on. We needed a whole new roof and unfortunately our budget dictatres fiberglass shingle instead of the original slate. Should we do the same to spray in the insulation in the exterior walls?

HoustonRemodeler
Re: Insulating concerns in a 100 year old house

Spray foam is great. With all the other leaks in your old home, I don't think you'll have problems making it too tight.

David Polando
Spray foam. Re: Insulating concerns in a 100 year old house

Spray foam, both closed and open cell has benefits, primarliy significant r value for closed and noise nitigation as well. Unfortunately, is can also be very bad for your house. In northern climes, stick and post and beam houses built before 1920 generally are sheathed with horizontal boards that receive the siding. The exterior walls of houses get wet a few ways - on the exterior from wind driven rains, snow and ice; from humidity from inside the house migrating through the walls and from plumbed or wet areas leaking.

When framing members get wet they will only dry satisfactorily if the breathe. Framing members cannot breathe if surrounded by spray in foam. Spray in foam is very bad for your your pre-twentieth century house.

In the next few decades people will be trying to remove the spray in foam much as has been happening with blown-in insulation which was so popular in the 70 and 80's.

I have taken entire sidewalls off and found sopping sheathing, wet framing members, window jambs etc.

keith3267
Re: Insulating concerns in a 100 year old house

Check you local libraries for a book called "From the Walls In" by Charles Wing. It is out of print but it may still be in your local library. This is the best source of information on restoring old houses and has a couple chapters on insulation.

Amazon.com still has some copies for sale.

netmouse
Re: Spray foam. Re: Insulating concerns in a 100 year old house
David Polando wrote:

In the next few decades people will be trying to remove the spray in foam much as has been happening with blown-in insulation which was so popular in the 70 and 80's.

Can you clarify? Are you referring to the prior decades when blown-in insulation had asbestos? And was widely used up through 1990's? Seems many houses are a real disaster.

I had my house insulated about 2 years ago after many interviews of contractors and research on internet, and under the state rebate program. Blown in cellulose with borate (without additive ammonium product) seemed the way to go for attic. I decided not to do the walls due to too much in research about leakage of fibers into the main house air. Plus that is very expensive and not sure on payback in fuel savings.

The contractor I hired used foam in basement around joists, etc.

I read too many concerns about fiberglass, especially the loose kind, so stayed away from that.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.