what rafter size

[chocolateteacup]

A bit of help needed with rafter sizing please,
i'm using marley wessex tiles(53kg/sqm).
rafter length is 4.5mtrs.( ridge to wall plate)
pitch is 18 deg.
without purlins if poss.
Thanks,
Chock.

 

[freddiemercurystwin]

Span table do not go up to that span so we would only be guessing.

 

[Static]

Depends alot on spacing but would be around the 50x225 for 400mm centres or 275x50 for 600mm centres.. may be able to reduce those a little if you up the timber grade..

Why are you trying to avoid purlins?

 

[catlad]

I wonder why the span tables dont go that far.....

 

[chocolateteacup]

thanks for replies,
looks like I'll have to go with purlins (raise party wall)
so with purlin at half way and rafters lapped at purlin what
size at 600mm c/c ?
Thanks again,
Choc

 

[Static]

50x125 rafters at 600mm c/c
Dont need to lap them at the purlin they can be continuous over the purlin.

 

[chocolateteacup]

thank you Static.

Chock.