Loft Insulation Material

5 Apr 2008
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United Kingdom
Hi there,

We've just moved house and I'm about to sort loft insulation in the property (it's between the joists but not across - and certainly not up to the 270mm we want to aim for). A couple of questions if that's ok:

1. Any suggestions on which type of loft insulation? We are looking at Rockwool rather than Glasswool (thicker, resistant to water, better fire resistance and easier to fit)

2. Then any thoughts on either Knauf (e.g. or Rockwool ( - seem to be broadly similar in size/length but price is very different, so is ther much quality difference?

Many thanks!
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We've just done our loft a couple of weeks ago - sounds like the same situation as yours just with existing insulation between the joists.
Used Knauf glasswool - 200mm loft insulation super top up layer (£25 a roll from Wickes). It was dead easy to lay and seemed decent quality so not sure i could argue its worth spending over twice as much for the rockwool!
I strongly recommend the mineral wool treated with Ecose, which prevents it shedding irritant dust and fibres. it is brownish.

It is made by Knauf but widely sold as an own brand. You will find "Ecose" printed on the packaging.

i react badly to the old yellow fibreglass and would actually clean it all out if I was re-insulating.

You can add counterbattens to give you additional joist depth that you can board over.

prices go up in winter and special offers abound.
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Knauf R-value 3.85m²K/W
Wickes R Value: 4.50 m2K/W

As a top up (law of diminishing returns) I'd get the Knauf.

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