March 5, 2008
Insulating the Closet Ceilings
My upstairs closets are built into the pitched eves of the house and therefore, have only 6 inches of dense-packed cellulose in the ceiling cavities. This is not enough insulation for the cold north... so I finally took action.
I'm installing 2 inch (around R-10) sheets of polystyrene foam board over the plaster ceilings in each of these closets. I'm trying to be careful about getting them very well sealed. I bought this nifty spray gun and several cans of the pictured spray foam. It lays narrow to wide bands of foam, depending on how far you pull the trigger. I'm applying beads of foam at all the joints. The sheets are being attached with both foam board glue and 3 inch screws with washers. Unfortunately, I will have to go over the top of all of this with a thermal barrier (ie., gypsum board or something) Dow makes a foam board that is somewhat rated for fire, but it's about $60 per sheet.
Of course, no job goes as smooth as it initially presents. In the first closet I started on, I tried to screw up some loose plaster before adding the foam... screws wouldn't pull the plaster up. I pried a bit of the plaster loose to see what was going on. Apparently a large upper attic fire in the early 1900s burnt sections of the wood lath holding the plaster to the ceiling... SO I had to tear off half of the plaster & lath before adding the foam board. From below the wood lath looked great. BUT the back side was completely charred and I was able to push my finger right through it. What a mess this tear out made!
Points of interest in the photos:
- the exposed conduit is feeding electric to the patio ceiling on the other side of the window
- the window is one of two that overlooks a very cool 2-story cathedral ceilinged patio with huge arched screened windows and tiled floors with floor drains (that don't work and actually drain into the basement at the moment-which reminds me...)
- the square wall cut out was used to feed new electric to a switch in the living room below
- When the spray gun starts to slow up and get clogged, you simply screw on this can of cleaner and spray it for a few seconds. It worked really well. Somehow the tip seals off when not being used so that the foam does not harden inside the gun, thus you can let it set for days/weeks without having to clean it all up.
- We're very fortunate. For an old house, we have huge walk-in closets. Six of them (and larger than the one pictured) upstairs alone. Is that crazy?!
- I am amazed at how even the insides of the closets are finished out with crown moulding above doors & windows... even the inside 2 attic spaces! Where have these guys gone?
Note: When cutting foam insulation, you will have pieces of pink foam shrapnel clinging to you for days. The stuff has a heck of a static charge!