waterproofing a flat concrete roof

Is there any provision for the rainwater to drain off or does it just puddle up and stay trapped? is there a fall?

yep slight fall to the back with gutter and downpipe

Regards

The usual solution in places like Italy where flat concrete roofs are normal is to lay a waterproof screed on the roof. This requires the roof to be clean and dry before you start.

Sounds identical to one I did myself once. IIRC I used bitumen paint as a cheapo solution, as I knew I'd be selling the place not long afterwards.

Seemed to do the job well enough; I can't vouch for it's longevity but think if I'd been intending on keeping the property for a long time I'd have chosen something more durable. Indeed, the purchaser's surveyor flagged it as a future maintenance issue.

David

yeah. Concrete itself is pretty impervious, depending on the grade.

Anything that soaks in a bit of a plasticky or tarry nature will improve it immensely.

Probably one of those render waterproofers will do.

having atempted all of the suggestions in this thread over the past thirty years, I have found only one solution and that is to use a product called 'cromapol'

Don't bother with anything available from B&Q et al, they also have expensive sealants, but none of them work on cracked concrete

It's available in black, white and grey

Having read all the other posts since my reply this am, I would also recommend the cromapol product or there's another called aquapol, I think... Check out JJ Roofing supplies or Wedge roofing, but again, it's not cheap- about £90 a tin retail, £60 trade. For a cheaper way of remedying it as a trial.... If you can find the crack get a tube of Sika Flex

Hth Deano

Cracked is different from porous, sure. I'd probably use epoxy mortar on cracks, but that stuff looks a useful thing to know as well

cracked?

Jim K

TMC mentioned it was cracked at 16:48 yesterday