Rafters, 6x2 and 3x2

[alpenbowl]

Biggest diy project ive done and need help. Its a brick outhouse attached to kitchen 3.2m wide by 2.4m long, pitch about 22deg. Fitted 5 rafters (6x2 timber) 450mm spaced then I ran out of 6x2 long enough to fit last two rafters than run along side the left and right walls.

Fitted 3x2 for the two remaing outer rafters, the birdsmouth cut for all rafters is on the inside of the wall and then the it runs flat on the wall plate so I sat the 3x2 on an extra piece on 6x2 I firmly attached to the wall plate to raise it up so all rafters are level.

Want to re use the natural slate and in Scotland so will use sarking board before doing this.

Its only going to be used as a decent shed but will the 3x2 be ok for the weight of the slate etc.

Options are, 1) Going to fit a support beam braced vertically against the wall half way along the span of the rafter to support the 3x2.

2) I have enough 6x2 to somehow brace 2 pieces together and use as rafters, (whats the best way of doing this?)

3) Last option is call jewsons again as only way I can get the timber this size to my house, they have messed up my timber orders twice so far so dont want to deal with them in a hurry.

 

[noseall]

Are you running a barge board up the outside of the gables - if so then the noggins that you fix to the last (3"x 2") rafter will offer support to that rafter via the gable wall.

Otherwise just fix a vertical prop against the gable to the underside mid-span of these two rafters.

...and, once you lap the sarking board onto the gable masonry, this will also lend a bit of support via the gable wall and the other rafters.

Lastly, slate is one of the lighter roofing products so i guess you will be ok.

 

[alpenbowl]

Thanks for that as forgot the sarking would be overlapping the gable ends so providing even more support, so the 3x2 is in with supports.

Sarking all on need to get the membrane on, was going to use this:
http://www.screwfix.com/p/protect-a1-roofing-underlay-1m-x-15m/31617

Any other ideas what to use to cover sarking before natural slate goes back on?