We have a covered, paved terrace surrounded by upwards-sloping land. Round the terrace is a low cinder block wall, then a concrete path which is higher than the terrace. The terrace gets a fair bit of water seeping into it (especially in Sydney's current weather!). I want to find a way to prevent that.
Between path and wall is a gap about 10-20mm wide which it seems someone tried to seal twice, once with concrete and then with some kind of black pitch or tar over the top. Neither has worked. The tar strip was coming loose and the concrete underneath has crumbled and can be pulled out by hand. I can easily remove what's left I think. The length is about 8-10 meters.
Wondering what I can put in the gap which will prevent rain on the path from going through the wall. I also think some water may go under the path from the surrounding lawn, so maybe I can also seal the inside of the wall with something.
Thanks for any suggestions!
Welcome to the Bunnings Workshop community @richard-sydney. It's sensational to have you join us, and many thanks for your question about preventing water seepage.
If you think water is getting under the path, then I'd recommend installing drainage along the edge of the path. Cut a 100mm wide strip of grass out next to the path. Next, dig a 100mm wide trench that is deeper than the terrace's surface along the path's edge. Place agline in the bottom of the trench graded towards your nearest stormwater pipe and connect it. Backfill the trench with drainage gravel up to 100mm from the surface. Place soil in the last 100mm and return the grass you cut away.
You can then remove the debris from the gap next to the wall and fill the void with Moroday 15mm x 5m White Gap Filler Rod. This saves you from using too much sealant. Keep the rod 10mm below the path's surface and then fill the last 10mm with Sikaflex 11FC.
It's a much better solution to stop the water from getting to the wall than trying to paint something on the inside of the wall. If you did want to go the route of a paintable water-proofer, then I'd suggest Crommelin 4L Exterior Grade Brushable Waterproofer. However, at a minimum, I'd recommend removing the paint off the inside of the wall with an angle grinder and wire brush wheel and sealing the corner where the wall meets the terrace's tile with Sikaflex instead of the grout which has likely cracked.
Please let me know if you have any questions.
Have you had a chance to repair the wall now that this weather is starting to ease Richard (@richard-sydney)? Please don't hesitate to let us know if you need further assistance.