Roof Insulation - What/Where to Buy

I'm going to re-insulate my loft. However, the joists are at non-standard spacings (due mainly to additional joists being fitted for a loft conversion), so the pre-cut rolls of fibreglass insulation are no use to me.

It used to be possible to buy uncut rolls of fibreglass insulation, but I can't find them any more.

Can anyone suggest a good source of insulation that I can cut to my chosen width?

I'm going to lay two layers of 100mm thick and will want a considerable quantity as the property is a bungalow.

Reply to
mlv
Loading thread data ...

How do you mean, 'uncut'? Unless you mean the loose-fill granular stuff?

The rolls of fibreglass insulation are fairly 'flexible' in that within reason they will fit between joist narrower than intended, and will bulk up a bit (ie, get deeper, = more insulation). If they are way too wide, just trim of the excess with a long carving knife while still rolled up (like cutting a swiss roll!) - if you have non-standard spacings you can be sure the surplus will be used up.

The second layer should be laid at 90deg to the first, so you'll have no joist issues there (and it will be much quicker to lay, too).

David

Reply to
Lobster

formatting link
that stuff?

Reply to
mogga

Surely with a loft conversion you wouldn't want to insulate between the joists anyway apart for sound reduction.

I'd have thought a good dose of insulation just under the tiles would be the best bet like cellotex/kingspan etc or am I missing something?

Reply to
PeTe33

I am assuming he means the bits of loft left that are not under the new floor (although may still be crossed by new joists) at the eves etc.

Noise insulation and fire resistance are other reasons for adding insulation.

You will need this as well, otherwise the loft rooms will be a tad freezing!

Reply to
John Rumm

Spot on John :-) Plus the loft conversion only covers about half the bungalow roof area (because the roof in the other areas was too low for conversion.

I am considering putting 100mm of insulation under the loft conversion floor to help keep the heat downstairs.

Yes, I'll be having that too!

Reply to
mlv

Fibreglass insulation usually comes in rolls that are 4ft long, pre-cut into

3 x 16inch widths.

As I don't want 16inch widths, I would prefer an uncut 4ft roll that I can cut into whatever widths I like.

Uncut rolls used to be readily available. They don't seem to be now.

Reply to
mlv

Hmm, i'm trying to find a supplier of Celotex in the Hampshire/Camberley area. Wickes and B&Q don't stock it ..

Any ideas all ?

Paul.

Reply to
zymurgy
[snip]

Travis Perkins in Fleet?

HTH, Cheers,

Reply to
Jim White

I just stumbled across the following

formatting link
like a bit of a non-descriptive directory of insulation suppliers, but It's got the company I got about 25 off 8'x4' (or whatever)sheets of

46mm cellotex delivered for about £400 which seemed like a good price.

formatting link
be similar companies in your area.

HTH

Reply to
PeTe33

Wickes stuff comes in the usual partial cut 3 width + an extra one right down the middle which fit's out widely spaced roof thingies spot on.

Though as others have said, just cutting before on-rolling and you can cut to any width you like. Then I guess you could use the off-cuts at 90 degrees without worrying about the width.

Reply to
PeTe33

IME of the isowool variety, it is only partially cut through. So if you cut it elsewhere and don't pull it apart at the pre-cut sections you get to have any size you want.

Reply to
John Rumm

Ah, missed the bungalow bit - hence why the BCO did not insist on it for fire protection (rules are less strict going from one storey to two than they are for two to three)

TBH, the under tile insulation is all you need in the bits covered by floor - since those rooms will presumably be heated and not dissimilar in temperature to the rest of the house the heat flow into them will be limited.

Reply to
John Rumm

Ask for the generic product (rigid foil covered PIR or urethane foam boards) rather than the Celotex brand name and you may have more luck (not to mention get it way cheaper).

Reply to
John Rumm

It falls to bits if the cuts are anywhere near the perforations, but can be OK. A panel saw is the best way to cut the roll, IMO.

Reply to
Chris Bacon

I laid mine across the joists and then cut to width with a stanley knife, across the top of the joists, but beware of cables. It cuts quite easily that way.

You can then put another layer over the joists if necessary.

Reply to
<me9

Reply to
<me9

I tried filling out the webform on their site last week to enquire about prices... Still waiting for a reply from them.

H
Reply to
Hamie

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.