Gable roof end rafters position, help needed

[Sevka]

Hello people, I am building a gable roof on cavity wall, gable both ends.

I am unsure how close the end rafters should be to the wall (the ones in the cavity and the first ones inside the building).

Should they be flush against the block work or should I leave a gap of say 20mm between rafter and block work?

Any help would be appreciated.

 

[foxhole]

Roofing forum?

 

[noseall]

They can be flush if you wish. If it is a cut roof (i.e. not trusses) this means that the ceiling joist will pass along side the rafters and will be roughly 50mm away from the gable wall. Ideal.

Are you building a cut gable or are you fitting a ladder set and barge boards etc?

Don't forget the restraint straps.

 

[Sevka]

Hi noseall, thanks for your reply.

I am building a cut gable.

One more question.....

What is the method for preventing sideways movement? "racking" I think its called.

Would diagonal restraints be ok and if so what size timber is generally used?

 

[catlad]

The purlins should give your roof enough strength.

 

[noseall]

I wouldn't worry too much about sway whilst building the roof. Just make sure that your first two pairs are parallel and that subsequent rafters are set the same distance apart.

In other words, don't be tempted to upright each pair of rafters with a level as the whole structure will sway and drive you barmy. Rather, get all the rafters in place and correctly spaced at the ridge and wall plate.

Once they are in place you can then diagonally brace them from the outside. Fix a batten once in the top left - then upright - then fix again in the bottom right and a few more other places.

You can then build the gable masonry along with any purlins, and straps and lock the whole thing in, then remove the diagonal brace.

 

[Sevka]

Thankyou for your help, its much appreciated.