It is currently 29 Mar 2024, 14:05
MY63 wrote:Thanks Roger that explains a lot. Although its minimum angle is 3 degrees with a 209 mm fall from ridge to wall. Should I consider revising my plan or will a 100mm fall be sufficient ?
I understand the junction of the rafter and the wall plate much better now.
9fingers wrote:Yes that is what I'm visualising.
Scaling off your drawing it looks like the rafters are inclined by 50-75mm along their length of about 1.3-1.4 m
Putting in a rafter as well would likely mean the top of the rafter would be height than the rafter.
Drawing out a detail section should show the problem.
Several bolts per rafter pair with serrated lock washers in between the rafters should be plenty strong enough and the decking and ceiling OSB should hold the rafter pairs at the rigth spacing making the ridge board redundant.
I'd only suggest this for such a low pitch which gives lots of overlap area in combination with such short rafters for your 2.4 m width.
Bob
MY63 wrote:Thanks Roger that explains a lot. Although its minimum angle is 3 degrees with a 209 mm fall from ridge to wall. Should I consider revising my plan or will a 100mm fall be sufficient ?
I understand the junction of the rafter and the wall plate much better now.
MY63 wrote:The fact that the over hang carries no weight makes things clearer to me I was having difficulty working out that junction. How deep should the opening (birdsmouth) be in the rafter was a question I was going to ask but if that is where the weight is transferred then I guess it will be the dimension of the wall plate.
Allowing maximum contact and weight transfer.
I am trying to find drawings I have previously seen showing this type of roof detail.
Thanks your help is appreciated
I have no idea if Sam's PM was telling you ...
RogerS wrote:Mike G has a very elegant method of building rooves such as the one you're doing and he posted about it in his workshop thread IIRC but damned if I can find it.
9fingers wrote:RogerS wrote:Mike G has a very elegant method of building rooves such as the one you're doing and he posted about it in his workshop thread IIRC but damned if I can find it.
When I built my cut roof for the workshop 10 x 3m, I made a couple of jury rigs to support things in roughly the right place and then went up a ladder to finally adjust them. My ridge board had to be in three pieces due to length so i used temp rafters to hold it in place before filling in with real rafters. Fixing with screws is much more forgiving than nails as you can adjust for cock-ups.
Bob
RogerS wrote:Mike G has a very elegant method of building rooves such as the one you're doing and he posted about it in his workshop thread IIRC but damned if I can find it.
EDIT: Found it. Bottom of page 6
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