Hi, new guy here having a go at a self build while living in it off grid.

[Mick67]

CLS timber from B&Q not heavy and cheap, max air fans not cheap but good

 

[Robmac]

CLS timber from B&Q not heavy and cheap, max air fans not cheap but good

I found it cheaper at Screwfix a few months back (3x2).

I rip it down the middle and find it plenty strong enough.