On 00:33 4 Oct 2020, Dave Liquorice said:
On Sat, 03 Oct 2020 22:12:15 +0100, Pamela wrote:

A short wall dividing two flat roofs absorbs rainwater, which leaks
from the brickwork into the roofspace below. The top and sides of the
wall were treated with bitumen paint which worked for a few years
before water got in again. This is the wall:

https://i.postimg.cc/sx1Q95B7/roof-wall-20201003-A.jpg

Remove railings, cap stones and first course of bricks. Cover exposed
top of wall with sheet lead that comes down the wall and over the top
the roof covering fillet, both sides. Relay new clean bricks and cap
stones, replace railings.

As a bit of lead to cover that width of wall and down the sides won't
be cheap you could probably get away with just lead flashing along the
edges and DMP immediatly above it. Ensure the lead and DPM have a slight
fall to the outside. The wall top covering needs to be contiguos to stop
water penetrating the wall. If there has to be a joint the edges along
the joint need to have a vertial bit of about an inch and an inverted U
cap over the top.

"Sealants" will just fail, again. Properly done lead/DPM will cure the
problem for good.


All very true and something to do in spring. Meanwhile the wall needs
sealing as rain water is entering and I'm not sure if I should get plain
bitumen paint, roofing bitumen paint or acrylic sealant paint.

This was my shortlist:

https://www.wilko.com/en-uk/ikopro-f...ator/p/0243442
https://www.screwfix.com/p/thompsons...oof-seal/46708
https://polarcoatings.co.uk/product/leakseal-500ml