Lean to Roof attaching RidgePlate to existing wall

[MRSOLO]

Hello, I am building a single storey extension with a standard lean to roof, the width of the extension is 3.5m and the roof pitch is 16 degrees. I have been recommended to use 7" * 2" rafters at 14" centres and my question is what size ridge plate should I attach to the house wall and what is the best method of attachment. ( the existing house is built of 9" cavity blocks) Was thinking a 8" * 2" ridge plate with a 2" * 2" section screwed on at the base (so the rafter sits on it as well ) and attaching this to the wall using whatever the biggest size hilti bolts (think its one inch diameter) are placed 20 " or 500mm apart. Appreciate if anyone can advise on the suitability of this arrangement. Thanks

 

[noseall]

an 8" x 2" ridge plate sounds good. 1/2" expansion bolts at 600 centres is ok.
no need for any 2" x 2" bearing timber just make sure that the rafter cut is snug.

fix the plate with screws first, fit the rafters, then fix with the bolts after. this will allow you to fit the rafters without worrying about landing on an awkward bolt sticking out beyond the plate.

 

[^woody^]

I would use a 4x2 timber for the plate, and fix this under the rafters so that the rafters and rafter point actually goes up to the wall - and the top lath (and top tile and flashing) then sit much better.

This saves the cost of the thicker timber and additional 2x2, and saves the labour time, and IMO is a much better job with less faffing about

I's use m10 expansion bolts, not 13mm

 

[MRSOLO]

Thanks guys I appreciate the advice. Cheers

 

[noseall]

I - and the top lath (and top tile and flashing) then sit much better.

the guy has a 16 deg pitch which will warrant concrete interlocking tiles.

because of the nib location, the top lath will be no where near the flat bit. the flashing will sit on the tiles.

some arch's specify below and some at the abutment.