DIYbanter - View Single Post - composite/metal purlins instead of timber ?

wrote:

I have a shallow pitch roof design that involves 225mm timber purlins
supporting 50mm counter-battens, then battens and interlocking concrete
tiles. Span of purlins is 4 metres. (Insulation between purlins based
in knauf insulation examples). Then purlins were to be hung from
masonry using joist hangers.
What could I replace the timber with in order to make the roof thinner
? I have no experience with composite beams etc.

Can we have a little more detail please. I guess you have 225 x 75
purlins, but I can't figure out the jack rafters. What size are the
battens and what is the weight of the tiles/sq M?

Regards
Capitol