Getting Insulation-Ready

by Josh on September 24, 2009 · 8 comments

in Bedroom,Journal

With the rough wiring done, the next step in the bedroom remodeling project has been to get the space ready for insulation.  Some of these steps were determined by choosing closed-cell polyurethane spray foam as the insulating material, others are based purely on my own preferences.  Here are my steps in insulation prep:

Seal off roof vents and any other large openings in the roof deck or openings to adjacent spaces not part of this project.  This is simply about keeping the expanding foam from going places it isn’t supposed to go.  Because the foam will be installed as a “hot roof,” the insulation will be sprayed directly against the underside of the roof boards with no air channel and no need for roof vents.  I’ll write more about the whats and whys of my choice of a hot roof insulation design in a future post.

Blocked Peak for Insulation text

Pull existing cellulose and fiberglass insulation away from the rim joist around the perimeter of the space. Although the rim is already insulated, replacing the fiberglass and cellulose with spray foam will make it better.  The R-value will be improved to match the roof and walls in the rest of the crawlspace, and the closed-cell foam’s air-sealing properties will help keep warm air on the first floor from leaking outside or creating condensation problems at the sill.

crawlspace decking 2

Remove excess cellulose from the floor in the crawlspaces and put down plywood decking. This isn’t really necessary, but by decking the crawlspace I cut down on cellulose mess and make it easy for the foam applicators to get where they need to work.  I figure the easier it is for them to move around, the less likely they will be to take shortcuts or make mistakes spraying the foam.

{ 8 comments… read them below or add one }

Nina September 24, 2009 at 7:08 pm

How much did this cost? I have a 1914 Craftsman Foursquare I want to do the entire house w/ foam. did you do it yourself?


Stacy September 29, 2009 at 7:39 am

I’ve always wondered about the insulation in my attic/crawlspace. So you can use the spray stuff directly on the roof boards? Can you then finish the ceiling by putting sheetrock or other boards across the 2X4’s (or whatever the up/down boards are? Or do you need to leave it open? I would like my attic area insulated (it’s not at all now, except the crawl spaces, but also would like it more user friendly. I also have a small window in the dormer area, does that make a difference?


Will September 29, 2009 at 11:12 am

Hmmm, we might need to chat sometime. Our project will soon be at this point and I would value your advice. This looks like a really good plan!


Josh September 29, 2009 at 10:13 pm

@Nina- I’m working on a cost analysis that you might find helpful. Stay tuned!

@Stacy- I’m not sure I am visualizing your space well enough to comment. I will try to do a post on the “hot roof” insulation method I’m using which may address some of your questions.

@Will- Happy to chat anytime!


Faye October 14, 2009 at 7:14 pm

Wow! Your attic area looks soooooooo clean! I know what its like just to get it to that point. It’s no easy task. No air vents? That’s interesting. I guess it won’t need ventilation?


Josh October 14, 2009 at 10:30 pm

That’s right, Faye. No roof ventilation is necessary with a hot roof, though I believe this insulation method currently voids most shingle manufacturers’ (archaic) warranties. I think this method is best suited to locations with more heating days than cooling days, so bear that in mind if you look into it.

Clean attic? According to Lavoisier’s principle of the Conservation of Mess, household messes can be neither created nor destroyed. If my attic is clean it is only because I’m letting the dishes pile up in the kitchen.


John Martin December 15, 2009 at 12:43 am

If there is no ventilation, what happens to all the moisture that rises up from the interior or the house?


John January 26, 2010 at 7:20 pm

With everything sealed up so tightly I would think that would get awfully hot in the summer.


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