what size timbers for a roof

firbyfred

I am building a shed with concrete blocks and cobbles, I am up to wall plate height and would like to check with someone if the roof timbers I plan to use will be adequate.

The pitch of the roof is approximately 35°

each spar length is 1.90M, I was going to use 50mm x 125mm timber, set out at 400mm centres

The internal length of the building is 3.6M so was going to use 150mm x 50mm for the ridge board

I was not going to use any purlins/beams to support the spars

I will be using new pan tiles to cover the roof.

Anyone think it will be okay?

T_T_2

What grade of timber will you be using? C16 or 24?

firbyfred

T_T wrote: »

What grade of timber will you be using? C16 or 24?

when I go to the local timber merchant I would say it was for roof timbers, I'm not sure which is best grade though.

Gloomendoom

A quick glance at Chudley's "Building Superstructure" would suggest that you could reduce the rafters to 100 by 50 and the ridge board down to 32mm thickness.

Are you going to use collars or joists to tie it all together? At 3.6m you are on the limit for a simple couple roof.

firbyfred

Gloomendoom wrote: »

A quick glance at Chudley's "Building Superstructure" would suggest that you could reduce the rafters to 100 by 50 and the ridge board down to 32mm thickness.

Are you going to use collars or joists to tie it all together? At 3.6m you are on the limit for a simple couple roof.

I was thinking of putting some, about 4/5 ceiling joists across, not to carry a ceiling but more for storage ie. ladders, bits of wood etc.

would that help?

Gloomendoom

firbyfred wrote: »

I was thinking of putting some, about 4/5 ceiling joists across, not to carry a ceiling but more for storage ie. ladders, bits of wood etc.

would that help?

Yes, definitely. Without joists or collars tying the rafters together, the weight of the roof will try and push your walls over.