Pitched roof clear span for rafters

[frankychops]

got a roof we're doing, 45deg pitch, covered in slate(0.35 kN/m²)

I've got 225x47(9x2) joists as a clear span. I was going for 400mm centres, would 450mm still pass regs? I'll double the rafters at velux windows.

any thoughts/opinions?

 

[catlad]

Sounds overkill to me!

 

[frankychops]

Sounds overkill to me!

Sounds like it….. however it looks like it’d just in the regs…..

 

[freddiemercurystwin]

There's something missing from your question.

 

[frankychops]

There's something missing from your question.

What’s that? Thanks

 

[freddiemercurystwin]

The span.

 

[frankychops]

really good point!!

4.9m.

 

[catlad]

I was taking an educated guess it would be under 6m.

 

[frankychops]

Looking at it, its fine at 450mm with 195mm so my 225's are golden.