Garden Office Roof - part 2

[rs6mra]

Hi guys,

I need some guidance as i am now in the position whereby i am about to put in place the OSB sheets on the roof. The problem is I got frustrated finding the angles of the rafters and installing them.
It was my intention to leave a 12mm gap between the top of the rafter and the top of the ridge beam....................however they are all over the place!!! The size is 14x10 so i can use almost full sheets of 8x4 but the question is do i rest the OSB sheets on the rafters and pack them or do i rest the sheets on the ridge beam and still pack them?

I will try and post some pics but no laughing...........

 

[RobinBHM]

Pics would help a great deal.

What roof membrane are you using -could you finish the osb boards to the tops of the rafters then plant a ridge cap on and dress your roof membrane or a lead flashing over?

 

[rs6mra]

Please see the photos attached.

 

[rs6mra]

In terms of membrane i intend using Dupont Tyvek house wrap but I am trying to source something cheaper

 

[SteveF]

I will probably get crucified for this
I would shim the rafters next to the ridge to the highest point and a few shims further down at fixing points
fit osb
expanding foam between osb and rafter to take up the gaps ...if you are not going to see it
maybe then expanding foam along ridge top
run along with knife to make level

 

[Lons]

Why shim it at all?
Depends what you're putting on top of the OSB as a final weathering material. (slates / tiles / felt / metal?) You could treat the sides of the roof seperately and make a ridge as an independant section. Bit like a half round ridge tile!
Or fix a round section timber and dress a lead ( or flashband) flashing over ).

Bob

ps - just realised it's part 2 so maybe I need to read part 1 (hammer)

 

[rs6mra]

Thanks for your suggestions. Roof finish is going to be roofing felt and then felt tiles. So light weight

 

[OLD]

Have you let the walls move outwards if so release the rafters and pull walls in to plumb with ratchet strap and refix .If they have been cut wrong then you need to add wood to fix. It may be as easy to strip and start again.