Rafter top plate height

[23vc]

For a lean-too cut roof, is there any rule of thumb for working out how high you can go with the rafter top bearer, taking into account the batten and tile profile? I’m trying to work out how high I can go with mine leaving enough room for the cover flashing under the upstairs window cill.
I’ve ordered a sample mendip , so I can hopefully work it out when I get it, but any general pearls of wisdom appreciated! Cheers

 

[noseall]

We usually locate ours beneath the rafter rather than butt the plumb cut against the face of bearer.

 

[23vc]

Yeah I was planning to do the same. I’m trying to work out the distance between rafter top and the mortar joint which the flashing will be cut into.

 

[tomfe]

You need 150mm of flashing, you can get away with 100mm or even 75.
So it's just roof covering thickness + if it's a warm roof, insulation thickness +deck + 150 for the flashing.

 

[23vc]

Nice one, thanks

 

[^woody^]

75mm for the tile and batten, then the rafter depth x 1.5 gives an approximate depth.

 

[23vc]

Thanks woody