Fibreglass insulation

[bluc]

Putting insulation in my shed. I have 100mm bearers in roof. I have a choice of 90mm bats or 145mm.
Would i get any benifit putting the 145mm bats in and compressing to fit instead of the 90mm ones?
I have read you will increase insulation benifit but not to full effect if compressed. Is this right?
145 compressed better then 90mm uncompressed but not as good as 145uncompressed.. :think:

[RuddyCrazy]

Bluc go for the 145's and if your roof beams are wood then nailing on some chicken wire to keep the insulation in place will be an easy job, now if the beams are steel then some large 3mm washers and rivet gun is all thats needed.

[bluc]

Cheers :handgestures-thumbupleft:

[Lesgold]

Hi bluc. I’d go for the 90mm batts. Part of the insulation properties of batts is the air space in between the glass fibres. Those air spaces reduce the transition of heat in either direction. Compress the fibres enough and you end up with glass.

[Dude]

What Lesgold said Bluc, compressing insulation reduces its efficiency.

[RuddyCrazy]

The reason I did say going with the thicker ones was by using chicken wire to hold them up they won't compress too much and will provide a much better performance. Ok so with the chicken wire is only going to compress the insulation a very small amount and having installed insulation on huge jobs a slight crush is always used not only to hold the panel fixed but I was told it is is best to over oversize rather than undersize.