What can be done about a poorly insulated apartment building?

March 31, 2008 1:04 PM

We live in a “vintage” 1920s three floor/six unit condo building. The plaster and lathe walls have their charm, but insulation was an unknown concept in 1920. Next winter, I don't want to freeze.

Our first floor residents (me) freeze while our third floor residents roast. They actually open windows in the dead of winter up there. Almost all of their radiators are closed yet they still roast. A brand new roof helps keep the heat in for them but did nothing for the lower floors.

I manage the bills and don't want to pay $350 per unit per month to heat the place.

Does anyone have experience with this kind of problem? Would getting cellulose blown into the walls make the first floor warmer? Can we just blow the first floor or do we have to do the whole building? Has anyone had this done? What did it cost you vs energy savings? Would you do it again?

posted by mrbugsentry to home & garden (5 comments total)

I can't speak to the insulation question, but it sounds to me like there's a problem with your heating system. The 3rd floor residents shouldn't have to shut off their radiators, and the whole building should be evenly heated by a system in good order.
Have you had a competent hot water heating tech. check it out?
Assuming you have a feed-and-return system, have you had your radiators balanced?
posted by Floydd at 2:11 PM on March 31

Any insulation will make a difference. A better choice than celluose is foam. It's quite a bit more expensive but it has twice the R value and will greatly reduce the stack effect that is one of the causes of the third floor openning the windows while the first floor freezes. Especially in a high degree heating location like Chicago the lack of a vapour barrier combined with cellulose can cause a problem with moisture condensing in your walls. Foam creates an air and vapour barrier.

And even half of $350 per unit per month can buy a lot of foam. To give you an idea you can buy DIY, cavity fill kits for about $630 for 50 cu feet. How much you'll need will depend on cavity thickness and wall composition.

Also you can do it in stages. Start with the north side of the first floor (or possibly the side facing the prevailing wind) and work your way south and up. You'll notice a difference immediately.
posted by Mitheral at 3:06 PM on March 31 [1 favorite]

Do you have Knob and Tube wiring?
posted by BrotherCaine at 11:34 PM on March 31

A word about foam: we had one contractor tell us that he couldn't do blow-in foam because there is no space to blow it into in older plaster-and-lath construction. He may just have been selling us a bill of goods, hoping for the higher cost work, but he said we'd have to replace the walls with dry wall and put insulation behind it at that point. Since we barely had money for the foam, needless to say we didn't have money to completely replace the walls (and have probably spent the equivalent in horrendous heating bills, but that's a story for another day.)

Was this true, or was he blowing smoke (if not foam)?
posted by nax at 7:49 AM on April 1

Actually, insulation probably won't do much to reduce the stack effect, but insulation is generally cost effective to install. Also, lack of a vapor barrier is generally not a problem. Having the vapor barrier on the wrong side (you want it on the warm side) or having two vapor barriers is more commonly an issue. And you certainly can do the insulation in stages, it just won't be very effective until it's complete. If you do go with the foam, it has the additional advantage of noise reduction and stiffening your building.

Foam is pretty expensive, but it sounds like it might be worthwhile in your case. You can check if you have enough cavity space just by cutting a small hole in the plaster. If you have more than an inch and a half or so, go for the cavity fill, or low rise foam. It's important that you use low rise because the pressure from expansion can blow out your walls. If you have more than two inches or so, cellulose is much much cheaper. Definitely cheaper to install cellulose in the ceiling.

The point about knob and tube wiring is well-taken. It's a violation of code to insulate over knob and tube.

Definitely get the heating system checked by someone who specializes in either steam or hot water. With steam heat the radiator is either on or off, there's not much adjusting to be done with the knob.

Nax

It's possible. I have a plaster over brick house that has no cavity space. But if you have space behind the plaster, you can probably insulate, unless the knob and tube is an issue.
posted by electroboy at 11:12 AM on April 1