What wood to support 3m. perspex roof?

[seanoge]

Building a shiplap shed with a Perspex sheet roof. It's 3 m. wide. What should I use to support the roof in one span?

 

[Tigercubrider]

how thick is the perspex?

 

[foxhole]

3x2 should do it at 400mm centres . Any less and it may curl in heat from sun.

 

[seanoge]

Perspex is 3 mm as far as I remember. I have already built it at 1,8m x 1.8m but now realise it's too small so removing Right side and extending it, so total should be 2.5m.(N0 more room. See pic

 

[Tigercubrider]

So it's corrugated plastic?

You'll need rafters where the sheets meet, and purlins plus a fall on the roof.

 

[seanoge]

Yes, corrugated and I have 2 x 2 at about 50cm. spaces going from left to right in the picture, so at right angle to the sheets. Holds it up fine but worried about extra length.