Exposed aggregrate in loggia
There are several areas where a white powdery material is coming up and appearing on the exposed aggregate. I wipe it away but it comes right back when the area dries. I have had my radiant heat tested for leaks but it is OK.
Does anyone know what this material is, where it comes from and what to do?
Thank you in advance...........
The white residue is called efflourescence and is usually caused by moisture. How recently was the aggregate installed?
The aggregate is original (1965) and the problem began about two yeaars ago.
It is a moisture issue. Check with your local building supply outlet for a topical solution that can alleviate the efflourescence and give you a temporary fix. Since it has started in the last couple of years and you have ruled out a radiant floor leak, try searching for possible moisture from landscape, neighbors' drainage, new sprinkler systems or plumbing. Another possibility is that the water table could be high in your area. I am not sure where you are located but certain sections of Palo Alto currently have a higher than normal water table.
I've not found any painted on solution that solved vapor/water pressure from the *NON* painted side.
They all get pushed off the surface. Even those which soak in a "bit" into the masonary.
Agree that your water table has changed and the real fix is to manage the water.
It can be as easy as changing the watering schedule on an automatic timer on your place or neighbors place.
Or a busted/leaky pipe somewhere.
