DIY Chimney Flashing RMH

Hi all,

I have a sloped roof with tiles and I have a  sticky lead slab (not actually lead, but a surrogate).

The Chimney for my RMH is installed, and now I need to waterproof it.

The internet only shows installing lead slabs on rectangular brick chimneys.

But  my chimney is a round 250mm tube.

Does anyone has some resources, schematics, video,... on installing flashing with a lead slab around a cylindrical chimney?

Thanks!


Edit: added some photos

Hi Pascal;
I hope you do not mind.
I moved your post to the RMH and the wood stove forums for you.

Can you show us pictures?
I have installed plenty of roof jacks, but never on a tile roof
I am unfamiliar with the term "sticky lead slab" or surrogate slab.

We have Permies members who live where tile roofs are more common; perhaps they will reply.

Lead flashing are normally made up on site from 3mm, flat lead sheet, quite easy to weld lead with a basic torch and fine nozzle.
I bet there are loads of youtube videos …..

Fox James wrote:Lead flashing are normally made up on site from 3mm, flat lead sheet, quite easy to weld lead with a basic torch and fine nozzle.
I bet there are loads of youtube videos …..

But unfortunately all these videos are explaining flashing on rectangular brick chimneys. But mine is a round metal chimney.

So I might be using the wrong search keywords

Welding is not needed because my leadfree sheet is self-adhesive (but not stretchable)

See image. One of the ideas is to cut out half a donut (1) to close the gap between the tube and the tile. And then to stick small (overlapping) strips (2) on the tube and that donut. And of cours same stuff on the back sideof the tube too, with the donut strips to overlap.

But I'm pretty sure this won't be 100% waterproof.

Hi Pascal,
I think you need some metal parts, the foil you got on it's own wont be enough I don't think.
You could start with something like this?

You could start with a half donut on the lower side of the chimney, with the ends tucked under the overlapping tiles at the sides. Rather than try to tack that to the chimney with separate small strips, you need to make those strips as wide as possible considering the bend of the pipe, starting at the lowest point, and overlapping each other by at least a few cm going up around the sides. The strips probably need to be triangular or trapezoidal so they still overlap as they spread out on the tiles. I would extend these strips far enough up and out to get a secure seal to the tiles and pipe, and of course where the tiles are above the chimney, tuck the strips under the tiles. Then I would wrap a wide strip all around the chimney to cover the tops of all the overlapping strips.

You may need some new wood framing under the tiles above the chimney opening to support the sealing strips from below. It might work best to add that framing after the sealing strips are in place.


The metal parts Benjamin shows would be a good start for a solid connection.