Exterior flagstone landing

by Allan
(Los Angeles, CA)

I have an exterior flagstone landing above an interior room. Normal to heavy rain isn't a problem, however, when it rains constantly and heavily for days, water seeps down into the ceiling of the room below. I suspect the problem stems from the issue of rain buildup absorbed by the stone and eventually working it's way through. Is there a sealer that might prevent this problem?

Comments for Exterior flagstone landing

Click here to add your own comments

by: David

Dear Allan,

That could be a big problem. Whenever you lay stone over another room, you need to install a rubber membrane that keeps water from seeping through.

With a lot of rain, the water will work its way through the stone and concrete and cause your leaks. I doubt that a sealer will solve that problem. However, give Prosoco a call at 1-800-255-4255 and inquire if they have a strong sealer for that kind of situation.

If they don't, the only thing I can think of is putting a plastic tarp over your stone any time a big rain is coming. I know that doesn't sound appealing, but I can't think of anything else short of tearing the stone out and re-installing it.

Great luck with your project!


Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Flagstone Question.