I was about to re-shingle my 2-bedroom cottage, when I re-discovered Dan Perkins’ November 2008 JLC article ‘Retrofitting an Insulated Cold Roof.’
My 1933, un-guttered, 3′ overhang hip roof (with a gable addition) has never had ice damage problems here in northern Illinois, but is woefully insulated (minimal original insulation with gaps and uninsulated areas over basement stair well/closets; additional batts laid over joists and old insulation with even bigger spaces; poor vapor barrier).
I’m looking to reduce cold wx heat loss, but also thinking the cold roof will also pay benefits in cooler home in summer. Since I don’t have ice problems, would I be better off doing a ‘regular’ re-shingle (I have to do that this year anyway) and sinking the money in other insulating upgrades?
I assume to get full value from retrofit I’d also need to re-side and insulate walls, but won’t be doing that for a couple of years.
Any techniques or advice on cold roof retrofitting would be appreciated. Thanks.
Jeff
Replies
What is the slope of your roof, and where is your ductwork run?
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
The hip roof is 9:12 and the gable addition is 14:12 (steep). No ductwork in the attic except for bathroom vents. Thanks.
Jeff
That is alot of room up there. Insulating the roof deck instead of the ceiling joists will make all of that attic space into conditioned space - the heat and cold you make for your living space will go here as well. With a shallower roofline, say a 3:13 or 4:12, you're only adding maybe 18% to your conditioned space, with your roof, your adding closer to 50% more area.
You may be better off blowing in a ton of cellulose into that attic space instead, and foaming any ceiling penetrations. Much cheaper to do too.
Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
I hadn't really considered the volume of the attic remaining a 'heat sink' for the rest of the house. Think I'll just re-shingle and work on fixing the insulation later. Thanks for your help, it really helped to have another perspective.
Jeff