Concrete Moisture

[freiburg]

Does anybody know of any tests to determine if a slab is dry enough to apply an isolation membrane and tiles?

I have a 7" thick slab, outdoors, on top of an old concrete slab, 8' X 12'. I am in dry, sunny, San Jose CA. Will 4 weeks be enough time for it to dry out? Does it matter if there is residual moisture, as long as the isolation membrane is well adhered?

Thanks -Henry

 

FRIEBURG,

Refer to the manufacturers recommendations regarding age of the new slab for membrane application.

Make sure slab top is clean and free of deleterious materials.

Twenty-eight days is the magical number for concrete to initially cure-out in regards to its design strength.

This dependant on proper placement, consolidation, finishing, and soil condition.

BRIAN

 

[7314]

Genneraly you should apply the isolation membrane right after concrete placement and vibration, if you are in a dry climate zone you should retard evaporation to prevent cracking.