Loft insulation advice

[devonwoody]

Recently done a living room refurbish, new ceiling boards etc.

The existing loft insulation (fibre glass upto 4" thick) was badly disturbed in places and I am wondering if this would be a good solution.

relay this on top of new plasterboards and then put firbreglass back on top.

http://www.diy.com/nav/build/insulation ... d=12108260

Anyone with experience of this product?

I don't want thicker insulation of 100mm because our loft is used for a lot of storage items and I do not want to part.

 

[RossJarvis]

Recently done a living room refurbish, new ceiling boards etc.

The existing loft insulation (fibre glass upto 4" thick) was badly disturbed in places and I am wondering if this would be a good solution.

relay this on top of new plasterboards and then put firbreglass back on top.

http://www.diy.com/nav/build/insulation ... d=12108260

Anyone with experience of this product?

I don't want thicker insulation of 100mm because our loft is used for a lot of storage items and I do not want to part.

I fitted this for a friend on a dormer window, along with a new window. I found it fairly easy to use. It replaced fibreglass matting insulating the sides. They said the area was much warmer than before, however I can't say if that was the foil stuff or the other work "making good", such as double glazed window etc.

 

[chippy1970]

That stuff appeared in the trade years ago and they said it would replace the usual celotex or fibreglass insulation in New builds . Well it never did as it was found out to be nowhere near as good as they thought. We still use celotex on all the new builds I work on.

 

[devonwoody]

Thanks Chippy, I suppose because I have a large amount of fibreglass insulation already, this foil insulation would still be an addition so I would not be losing effect but getting a plus.

However if the reflective foil is covered with fibreglass, perhaps it would do nothing?

 

[RogerS]

Recently done a living room refurbish, new ceiling boards etc.

The existing loft insulation (fibre glass upto 4" thick) was badly disturbed in places and I am wondering if this would be a good solution.

relay this on top of new plasterboards and then put firbreglass back on top.

http://www.diy.com/nav/build/insulation ... d=12108260

Anyone with experience of this product?

I don't want thicker insulation of 100mm because our loft is used for a lot of storage items and I do not want to part.

Useless, DW...a lot of building controls will not accept this stuff

 

[No skills]

I've got this under the floor in the front room. It did make a small difference compared to before installation but had I been more flush and better educated I would of used cellotex or similar. Hindsight, its great.

 

[Lons]

I haven't searched but the big sheds, B&Q and Wickes etc. usually have really good promotions an around this time of year on "top up" glassfibre so you would buy 180 or 200mm thick to bring it up to regs. I did this with mine a couple of years ago and it cost very little.

Bob

#-o Just read the rest of your post about not wanting thicker insulation

 

[Jacob]

Is no good I'm told.
I'd put glass fibre between the joists, 3" celotex or similar over them with all the seams taped. Then 6mm plywood on top for light loading only. Loses 3" of height but good value insulation. If you can lose more space and get up to 12" celotex in this is worth doing.
Detailing important - pay particular attention to the joist spaces at the ends and sides, near the external walls or roof and pack them well so that the space can't get cooled under the insulation.

 

[devonwoody]

I would like to have thicker (and greater insulation) but I also must have the loft for storage use.

How is this possible if insulation is above joists level?

 

[No skills]

Can you insulate the rafters instead? Maybe with the super quilt stuff?

 

[devonwoody]

Can you insulate the rafters instead? Maybe with the super quilt stuff?

Yes that's possible, I recall many years ago we had a newly built house where that was done, but these days of ventilated soffit boards I cant see the point.

 

[RogerS]

dw....I remember I used something very similar to lag a hot water pipe/joints/etc where normal pipe insulation wouldn't easily go. When I touch the outside of this foil, it is noticeably warm to the touch. When I touch the adjacent pipe insulation it is cold. OK...the foil stuff is better than nothing, I guess, but personally I don't think it worth the effort or money. Bit like double-glazing windows.....payback period measured in decades.

 

[Jacob]

I would like to have thicker (and greater insulation) but I also must have the loft for storage use.

How is this possible if insulation is above joists level?

Plywood on top of the insulation. Means you can store stuff but not a proper floor for regular use.

 

[Lons]

pay particular attention to the joist spaces at the ends and sides, near the external walls or roof and pack them well so that the space can't get cooled under the insulation.

You would need to check the method of roof space ventilation before doing that as if soffit type vents. Nothing wrong with what Jacob said except that the insulation must not block the ventilation path from the soffit, that would definately not be a good idea! Not an easy task to get that detail right in the restricted space available, especially for those of less than nimble ability or body larger than twiggy type :lol:
Ventilation is a very important part of the construction and building regs - it's there for a good reason.

Bob

 

[devonwoody]

I would like to have thicker (and greater insulation) but I also must have the loft for storage use.

How is this possible if insulation is above joists level?

Plywood on top of the insulation. Means you can store stuff but not a proper floor for regular use.

Jacob I appreciate what you are saying but to walk across the loft on top of the plywood would compress the insulation down and also then press the plasterboard ceiling down because of the weight pressure. At present I walk on joists and avoid the bits inbetween. Your systems would require packing with timber to the top of insulation level?
Or what do you suggest.

 

[Jacob]

I would like to have thicker (and greater insulation) but I also must have the loft for storage use.

How is this possible if insulation is above joists level?

Plywood on top of the insulation. Means you can store stuff but not a proper floor for regular use.

Jacob I appreciate what you are saying but to walk across the loft on top of the plywood would compress the insulation down and also then press the plasterboard ceiling down because of the weight pressure. At present I walk on joists and avoid the bits inbetween. Your systems would require packing with timber to the top of insulation level?
Or what do you suggest.

3" thick celotex/kingspan etc is a fairly stiff board and you'd span it over the joists not between them, but would need ply on top to take any weight. It wouldn't take a lot of weight but enough to support the typical loft stored bits and bobs of furniture and stuff that nobody really wants and would be better chucked out!

 

[devonwoody]

Its getting to the cold water tank (for maintenance), its nowhere near the loft opening.
These are some of the problems with this increased insulation. Storing your three holiday suitcases etc. I do not have the space in our home, that's what I use the loft space for etc.

I think I will have to pay the energy company and suffer the loss and not have that extra insulation.

 

[Jacob]

Its getting to the cold water tank (for maintenance), its nowhere near the loft opening.
These are some of the problems with this increased insulation. Storing your three holiday suitcases etc. I do not have the space in our home, that's what I use the loft space for etc.

I think I will have to pay the energy company and suffer the loss and not have that extra insulation.

You could walk on the ply no prob. It's just not strong enough as a proper floor for everyday use. So suitcases etc access to the tank no prob. The tank would want boxing in with insulaton over/around but not under it.

 

[axe]

Not sure if you can afford to lose the headroom but you could use this -

http://www.loftzone.co.uk/storefloor.html

 

[MMUK]

One thing to remember, and this is extremely important, if you have any cables in the ceiling void you must leave an air gap around them. Try pinning cables to joists wherever possible and leave an insulation gap of at least 1 1/2" around the cable. If you pack insulation tight to the cable, especially fibreglass, you could end up with a fire.