Thread: How do I waterproof a leaking Pebblecrete covered slab?

Originally Posted by jasonv

After years of lurking on this forum to find answers to the many problems I inherited when I bought my house I've finally encountered a problem that I can't find a solution for on here!

I have a 12m2 concrete slab on an exposed upstairs balcony that's covered with pebblecrete. Underneath this balcony is a downstairs rumpus room, which has large water stains on the gyprock ceiling. Some are old stains but are clearly getting worse.

The pebblecrete has a few fine cracks in it, you can only notice the cracks when the slab is wet (except for one crack which was filled with silicon by the previous owner), overall the slab is in good nick appearance wise. Tiling or concreting over the pebblecrete is not an option as the outside floor level is only 20mm or so lower than the inside level.

Is there a clear waterproofing product that I can use that's designed for pebblecrete or similar? As the area is completed exposed from both the north and east it cops a lot of direct sunlight, does that make any difference? It will also need to be tough enough to cope with foot traffic and little kids on bikes, etc.

I thought products to seal pebblecrete would be plentiful considering how many swimming pools have it but I haven't found any useful information on the net. Any help would be greatly appreciated.

Thanks,
Jason

Pictures would be good, but I am thinking if it goes thru the slab, there is a problem with it as well. I am thinking if the previous owner siliconed it, there is an ongoing problem there, I would remove the pebble crete, repair cracks in the slab and tile or pebblecrete again.