Lean to extension lead finishing/height

[an203888]

I have a lean to extension I am doing and the pitch will be about 16° so I dont have a lot to play with (the roof windows and tiles are 15° min)

The ridge of the roof will sit under the upstairs windows and I obviously want to get this as close as possible. My plans seem to indicate the lead work going directly underneath the exterior sill, firstly is this deemed acceptable? Secondly, what is the shortest distance that can be left between that and the top of the tile?

I have attached a couple of pics of my plans for clarity.

Close Up

• an203888
• 20 Dec 2019

Lean too plan

• an203888
• 20 Dec 2019

 

[Notch7]

150mm is ideal vertical distance

75mm is probably ok for minimum.

Yes lead can go under cill.

Note the lead doesnt have to be 1 piece, you can have 1 width of lead going up roof then up the wall, then another piece going in wall and down to extension roof.

 

[an203888]

150mm is ideal vertical distance

75mm is probably ok for minimum.

Yes lead can go under cill.

Note the lead doesnt have to be 1 piece, you can have 1 width of lead going up roof then up the wall, then another piece going in wall and down to extension roof.

Thanks for the reply

Will BC care if its 150 or 75mm do you know? Also how does the second bit of lead going up roof and wall get held in place?

Thanks

 

[^woody^]

Lead can be tucked under a cill with no upstand - the 150mm dimension relates to vertical wall abutments.

But it must be chased in and properly sealed

Tiles and be close up too, as long as there is a small gap for the cill to drip

 

[an203888]

Lead can be tucked under a cill with no upstand - the 150mm dimension relates to vertical wall abutments.

But it must be chased in and properly sealed

Tiles and be close up too, as long as there is a small gap for the cill to drip

So it can have almost no height between the roof and the lead as long as the edge of the cill can drip down. Like the picture below:

Diagram

• an203888
• 20 Dec 2019

 

[^woody^]

Yes, that's it in principle. The limiting factor is how much room you need below the cill to fix the batten and hook the tile on.

Just remember to chase the lead in first, pin it, seal/point it and then bend it up to get the tiles and lath in, then dress it down, and the seal/pointing should be still intact. Or even put the lead in before the rafters if that gives more room to work with it.

 

[an203888]

Yes, that's it in principle. The limiting factor is how much room you need below the cill to fix the batten and hook the tile on.

Just remember to chase the lead in first, pin it, seal/point it and then bend it up to get the tiles and lath in, then dress it down, and the seal/pointing should be still intact. Or even put the lead in before the rafters if that gives more room to work with it.

Very helpful, thankyou