Fibreglass insulation rolls

bibibobo

Hi, Looking to insulate the attic very soon. Is it possible to get rolls of fibreglass insulation which are the width of standard ceiling joists and 200mm depth/height. Are these available rolled in plastic vapour check membrane? How much could I expect to pay for a roll and would it be cheaper from uvalue.ie or a builder providers?
thanks.

wasim21k

dont know about uvalue.ie but in B&Q they have each roll i think 13 euro each.

northdublin

recently did my own attic and i bought rolls of 150 mm thick fibreglass insulation. the roll itself is about 4 foot long which i then cut into three sections using a hand saw, this gives you three smaller rolls that are approx the width of a standard ceiling joist gap....16'' approx.
i got them in my local builder providers and each roll cost 30 euro approx

baldieman

What dept are your joists? If you have 6" joists for example than 6" fiberglass may be more suitable. The reason for this is you dont want to compress your insulation to meet the top of your joists as this reduces its value and the 6" would further. The problem is, how do you get thicker insulation than your joists. So I'll describe what I do.
Your first layer goes between the joists as normal. Making sure to cover the wallplate or up to it and yet insure to leave an air gap between the felt and fiberglass to insure ventilation from outside. (The rolls come pre cut 400mm although you have some cutting or prizing apart.) Insure a snug fit but try not to compress.
Then consider the space in you attic where you may want to use or need to walk on for access. Keep that area to the minimum. Then the rest, particularly in under the eves roll out another roll of 4" or 6" the opposite direction. If its done properly it should look like one single quilt cover.
That would be a good insulation job. If you want to improve on that, the area in the center which has'nt double layer can be up graded using superquilt 19 or other multi layer foil insulation.
To do this, compress the visible insulation between the joists slightly, 25mm approx. The superfoil can be then rolled over this area, stapled or nailed at one end, pull tight and staple as you go. The width of the foil should be about 300mm wider than the width you've left to walk on ie. between the 2 upper layers of fiberglass. So when fitting the foil these two edges should be temporarily lifted back. The fiberglass should be re fitted snugly along the foil. At this point you need short lengths of 2 x 1 timber. Feel for the joists and nail the 2 x 1's along these (take care to deal with electric wires) You can now floor over this area for convenience. The 2x1 is important to maintain a sufficient air gap between the foil and floor boards.
In most houses the ceiling is where most heat is lost without sufficient insulation and is the simplest and cheapest to fix.

gsxr1

before going anywhere near B&Q. Go to your providers. Check the price.

get the wide rolls your can cut yourself with a handsaw. A whole roll at a time. Joists can be spaced at 600 in some houses making the stuff in B&Q useless if it is 400mm wide.

cover in between joists well and your investment should pay for itself soon.

beware of down-lighters and clear ventilation near your eves (wall plate).

I have rarely seen B&Q cheap when buying proper construction materials.

kind of like going to Halfords as apposed to your motor factors when you need new engine parts

jack of all

gsxr1 wrote: »

before going anywhere near B&Q. Go to your providers. Check the price.....I have rarely seen B&Q cheap when buying proper construction materials.....kind of like going to Halfords as apposed to your motor factors when you need new engine parts

+1
I rarely buy tools or materials from B&Q, Homebase or Woodies etc (unless it's something unusual that can't be got elsewhere; your local providers will nearly always be cheaper for materials, and if you're buying a substantial amount of material you'll usually get a small discount if you ask.