Lift insulation. Advice on what exactly are requirements

Aubrey_Thicket

Hi all

My Sister and her hubby have just renovated an old mid terraced house. They took all ceilings down and re-boarded and replastered every ceiling. It is now time for the loft insulation and quite frankly there's lots of differing information on the web. Can someone please tell me.
What is required here? A friend told me it should be 4" thick and will cost about £400. Another friend told me "It needs to run 2 ways (1 way in line with joists and then kriss Krossed over) and should be thicker than 4"". So please, can somebody tell me what the required is?
My Sister wants to ring up an insulation company and TELL them what she wants as opposed to them possibly telling her something she can't verify is correct. I also read somewhere that this industry is full of cowboys who do a substandard job using cheap insulation but because the Man in the Street has no idea they get away with it
Any help please?
Thanks all.

Aubrey_Thicket

Loft insulation !!!!!! not lift. Predictive text!!!!!

Silver-Surfer_2

270mm.....

cajef

^^^

As above

Google is your friend

270 mm

The recommended depth of blanket style insulation (glass or mineral wool) for a loft is 250 to 270 mm. If you already have insulation, but it was put in some time ago, it is worth checking the depth, as only a few years ago the recommended depth of insulation was 200mm, and before that it was as low as 100mm.

Aubrey_Thicket

Thank you but even though Google does say 270 it also quotes other figures from other sites.

So, please tell me. Does this 270mm have to be kriss Krossed is is it just a straight run of insulation 270mm thick?

Thank you.

leveller2911

The key word her is "recommended" because unless its a new build there is no "requirement" to fit 100mm , 200mm or 300 mm .


They can fit whatever thickness and material they wish. I would just fit 100mm of Celotex between the joists and then floor over the top for storage.

TheCyclingProgrammer

Normally 100mm between the joists and 170mm across the joists. You'll get rolls in these thicknesses.

If you want storage you'll probably want to use something like loft legs or LoftZone kits so you can lay chipboard loft panels above the insulation (and allow for some air flow).

When you lay the insulation make sure you don't block any eaves ventilation.

PheoUK

Diminishing returns though once you et above 140mm... Check the pay back period.