Timber type, sizes and uses

[Delinquent]

Due to my architect being somewhere between stupid and useless, I now have a lovely blockwork extension with walls all finished, but the need to entirely re-design the roof.

So...

Where can I find info on what sort of timbers will do what sort of span, and what sort of sizes are needed for rafters, ridge boards etc? I've heard talk of a "timber bible" from the BCO (who very kindly showed me why the architects could be safely ignored on their choice of chamber joist timber and use something a at half the price) but so far a copy of it (or in fact it's name) has eluded me.

Whilst complex, the roof isn't that big or covering any great span which makes me question the S.E.'s spec as well - coupled with the fact that for some unknown reason his plans show half the existing timbers removed then replaced with massive great lumps of steel with posts bolted on!!! Had an old and trusted chippie look over the S.E. plans, at which he had trouble expressing his contempt for them due to the constant laughter

 

[^woody^]

Google " timber span tables "

The previous ones quoted in the b/regs and used on some building control guides were by TRADA, but they withdrew them and started to charge for them, but you can still find some free via google

Ridgeboards can be 25mm thick and depth to suit the rafter cut ( 175 or 200mm normally) there are no tables for them as they are not really structural members

Same for hips, but normally 50mm wide

 

[Delinquent]

Google " timber span tables "

The previous ones quoted in the b/regs and used on some building control guides were by TRADA, but they withdrew them and started to charge for them, but you can still find some free via google

Ridgeboards can be 25mm thick and depth to suit the rafter cut ( 175 or 200mm normally) there are no tables for them as they are not really structural members

Same for hips, but normally 50mm wide

Many Thanks Woody, got em

excellent info on the ridgeboards & hips too cheers, now just need to calc up the purlins joists and rafters - for some reason the S.E. originally specced some seriously overweight stuff due to removing the original rafters, but there is no need to remove anything so hopefully can get away with considerably lighter!