conservatory roof joists

[chalkedup]

hello
ive currently got a twin wall polycarbonate roof on the conservatory, but its been leaking a few years minus the temp fixes.
its 4mx6m wide and has 4"x2" joists and i want to change it to a ply roof with epdm then plasterboard the ceiling and skim.
can i use 4"x2" joists , will they hold the extra weight? or will i need 6"x2" joists?

the problem is that the toilet waste isnt much above the roof height so if i need 6x2`s i will need to raise that.

thanks for your help

 

[Static]

In short no..
Polycarb roofs aren't designed to have someone standing on them, whereas a flat roof will, so you will need something like 8x2" (195x47mm) at 600mm centers spanning the 4m.

 

[chalkedup]

cheers Static
looks like i might need to build a step to raise the toilet a bit lol