Terry wrote:

From here I just did a quick search: try www.jablite.co.uk

So did I - but it says nothing about stiffness.


That site also mentions the availability of a technical guide for
Jablite.

How useful of them to mention that.


It also mentions that "Jablite is produced for spans of 600 mm,
450 mm and 400 mm".
Therefore/ergo (how come there isn't a key for that three dot
symbol?) 1.5m (1500 mm) sounds like a large span?

Reasoning is flawed. The reason it's available in 400/450/600 is
because they are common rafter spacings. It's also avialable in
8'x4' sheets.

--
Grunff