Rendering advice - above and below - need flashing and bitumen?

[adysaes]

Afternoon all - I'm desperately in need of some advice.


I've just had the ground floor of our victorian property lime rendered at the back (we've done a ground floor remodel so there were lots of bricked up openings/new openings etc that needed tidying up), so the render stops at the first floor. The guy who did the job advised that, because it stops at the first floor, I might need to install flashing all along the very top edge of the render to stop water from getting in behind the render and frost damage occurring. On two of the three walls in question there are roof eaves and guttering at the top of the first floor that go over the render however on our very back wall there's no eaves or guttering whatsoever and the roof stops flush with the brick wall below it (unusual, I know). This would mean that in theory rain could drop down directly on the render.


So... long story short... where the render is only going over the ground floor and not the first floor (and where there aren't eaves covering one of the three walls) is it advisable to place some sort of flashing at the top of it? And would flashband be suitable or would it need to be lead?

Secondly the renderer mentioned that, on the bottom two courses of brick at ground floor that sit below the render, we might want to paint bitumen below the render to keep moisture from seeping through. However I've also seen on forums that this is a bad idea (could perhaps stop moisture also from escaping and cause damp to build up in side) - what are the thoughts on this?

[sammy.se]

Firstly, congratulations on using lime and not cement!!

Regarding the bitumen, I personally would not use that, but maybe your builder suggested it because of the ground layout. Is the rainfall flowing away from the house, or towards?

[wes56]

By lime render do you mean a 4:1 mix of sand and lime?
Where the render finishes at the first floor you can use a plastic stop-bead suitable for render.
At the base of the render finish just above the DPC line by using a plastic or SS BellCast. That way you wont bridge the DPC.
Leave the brickwork below the BellCast open and exposed - dont render over it or use any Bitumen or anything else.