Hi everyone, I have a finished plaster and lath room which was previously built in the attic, I have just gutted it due to really bad cracks etc. it was not previously insulated, i would like to use it year round the roof rafters are 1 3/4“ x 5 3/4“, does anyone know which insulation would be better, the fibreglass or the ridgid type? I believe there should be a gap between the insulation and the roof for air flow? is this correct? Thanks in advance !
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Yes, you most definitely need an air space. Where I am (Toronto) code is min. 2 3/4" air space. I think you can cheat this a little if you use baffles. ( corrigated styrofoam ) Still only get about "r" 12 with fibreglass. You can also use spray foam insulation, no venting required. (sandwich roof construction ) foam gives about "r" 6 per inch, so you would have 30+. Downside is cost and you can not diy.
Thanx Kidder, I`m a bit confused still, I have to forget the sprayed in stuff due to time/ $ constraints, if I deduct the 2 3/4``air space from my rafter thickness at 53/4`` leaves me with only 3``which I could only get in R13 normally used for 2 x 4 walls, I`m down in the n.e. u.s. Bridgeport ct. by the way hows your winter been up there?
depending on your head room, r-13 fiberglass then 1" ridge foam covered with 1/2 inch drywall would probably give you about r-20, more if you use 2" foam - I'm sure someone else has a better way and more details
Thanx a lot! sounds good to me, makes sense.
With no clue as to your location (climate) it's hard to say what might be best.
I believe there should be a gap between the insulation and the roof for air flow?
Do you have a ridge vent? If no, there's no reason for a vent channel.
So, how bout some more info? Then you might get some useful advice rather than WAGs.
Joe H
thanx, I am definitely going to put in a ridge vent, that`s part of the problem.
Part of what problem?
You have a problem other than it's cold up there?
More info needed.
Joe H