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Waterproofing a Stone porch

I have a question about waterproofing a stone porch. The porch is covered with stone (something like marble). There are relatively thin rectangular slabs placed closely together. Underneath, there are concrete blocks. Under the porch is an open storage space. There is rain that is hitting the porch and seeping through the cracks between the stones. In the storage space below, you can see icicles during winter. Some of this water is travelling into my neighbor's outer wall and causing water damage in his living room.

The solution provided to me was to remove the stone, put down an insulating layer to stop the water and cover it with new tiles. I was wondering if there is another solution. Perhaps a clear sealant that can be painted on the existing stone to keep the water out.

Any ideas?

Re: Waterproofing a Stone porch

I had the same problem only my deck was covered with 12x12 saltillo tiles. The grout shrunk and developed some hairline cracks. I did have a waterproof membrane below the tiles (I thought) but was still getting water in the closet ceiling below.

Rather than tearing up the tiles and doing something with the waterproofing, I bought some caulking for cement. I masked off each tile (what a pain) and squeezed a little line of caulk on the seams. I rubbed it in with my finger so it pushed the caulking into the cracks. It did the trick. The caulk didn't match the color of the grout too well at first but as time went on, it got dirty, etc. and then toned itself down. I've read about sprinkling sand on top of the caulk while it's still wet and it will color the grout to some degree.

End result, it worked but not an easy job. Just for peace of mind, I still re-do it every two years or so.

Good Luck.

Re: Waterproofing a Stone porch

Thank you for responding. That does sound like a good idea but I have some complications that may not make it work. These stones only have a hairline crack between them and some of the stones themselves have hairline cracks.

But I'm glad that you gave me those hints as I now have something to consider as a solution (which I really need). :)

I'm guessing there is no waterproofing paint kind of thing then?

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