Quilted vs Rigid insulation

littlemiss19

Hi everyone,

Me again! 

We are getting a new ceiling put into the back bedroom and the builders have asked us if we want to have quilted or rigid insulation. The rigid insulation will be £110 more. The room is 3m x 3.25m. 

The ceiling will be suspended as the roof is at the back of the house on the annex and is a shed shape (sloping to one side). 


My question is: what are the benefits of rigid insulation and is it worth the extra money?

Many thanks for your advice,

Littlemiss

FreeBear

I take it you mean this stuff - https://ybsinsulation.com/brands/superquilt/

Whilst it may be good at reflecting radiant heat, it is a poor performer when it comes to conducted heat. In a roof space, you want/need insulation that has a high resistance to conducted heat. So 150mm of Celotex/Kingspan would be preferable (in my opinion) and you get a foil facing which will reflect a small amount of radiant heat back.

You only get one chance to insulate, so do it well - £110 is a trivial expense compared to the total cost of the job.

ThisIsWeird

Seconded.

'Rigid' has a fixed and known thickness, and hence U-value. Quilted can be compressed, is often stapled into place (ie - it's compressed...), and I frankly wouldn't trust it to provide the stated U-value, unless installed with great care.

Worth asking, I think, for details on how they propose to install the rigid, too. I presume it'll largely be cut to fit in between the rafters and joists, but I'd personally like a layer - even if only a 1" one - over-boarded to provide a complete blanket of insulation, no cold spots, no gaps.