On Wednesday, 13 March 2019 21:18:51 UTC, JimK wrote:
Mathew Newton Wrote in message:
Just taken delivery of a number of Celotex GA4000 PIR insulation boards and, as shown in the photo below, the 100mm boards in the foreground are extremely wrinkled one foil face, particularly when compared with the completely smooth 30mm and 12mm boards in the background:

http://www.newtonnet.co.uk/permanent/celotex.jpg

The 100mm boards also have an ever so slight bow to them; not enough to cause me an issue but I wondered if the bowing and wrinkles were the result of differential shrinkage within the core?

Any cause for concern?


Are the wrinkles on the "inside" of the bow iyswim?

I wonder if they'll come right after temps have stabilised across
/through them?
--
Think about it.
They are intended to go where it's hot on one side and cold on the other.

They seem to have a lot of seconds judging by the market. Usually they have voids in the foam or mechanical damage.