C16 rafters vs oak?

[PhilC]

Hi, not sure if anyone can help here as it might be more of a building type question but............

I'm the process of building a new conservatory and C16 rafters have been specified but I would like to consider having exposed rafter tails, in which case I thought of using oak rafters instead.
I would keep to the same size of rafters but if I do opt for oak does the oak have to be graded and if so what is the equivalent grade or would it just be assumed that size for size oak rafters would out perform C16 softwood?

Many thanks.

 

[JandK]

Hi PhilC

As far as I know when it concerns construction as for instance in a building all timbers need to be graded.

HTH
Jan

 

[PAC1]

C16 is a structural stress graded timber. Oak can be structurally graded but you would need to buy the graded oak see http://www.trada.co.uk/faq/list/strengt ... d%20timber

 

[RobinBHM]

I dont think you can assume hardwood will exceed softwood in strength grading. The difficulty with hardwood is that there could be sloping grain, fundamental knots, surface checking, thunder shakes etc. C16 softwood is machine tested to a known strength so should be predictable.

Hardwoods can be graded and Im sure green oak used by timber frame companies must achieve a grading rule, but Ive not come across any timber merchant offering graded oak. I guess its worth phoning a few to see. EC timber is in Sussex or maybe Brooks Bros or Lathams, both in Essex

 

[PhilC]

Many thanks, I'll get on the phone.

 

[oakfield]

Obviously I don't know exactly what you are planning on building, but if it's just the ends of the rafters you want exposed would it be possible to stop the c16 rafters at the wall plate and bolt some oak rafters along side for the last couple of foot?
This would probably work out considerably cheaper.

 

[owen]

You could always just clad the ends of the rafters in oak if that's the look you're after.

 

[owen]

You could always just clad the ends of the rafters in oak if that's the look you're after.

 

[PhilC]

Thanks for all the replies and ideas but as the rafters are quite short it might be just easier to use oak all the way through but I'll investigate.
Also came across this useful guide which shows the relative strengths etc which might be of use should anyone come across this thread in a search.
http://www.roymech.co.uk/Useful_Tables/ ... esign.html