Can moisture from the sand and aggregate under a slab cause rising damp?

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Can moisture from the sand and aggregate under a slab cause rising damp?

Frederick Beggy June 9, 2022

I want to do a similar job raising a floor by 1 foot 2 inches to the level of an existing kitchen floor. The floor to be levelled is a concrete slab floor and in good condition. My plan was to lay four inches of aggregate /crushed rock topped with 2 inches of sand with a sheet of plastic layed on top of the sand. On top of the sand I intend to put 4 inches of insulation foam with a radon barrier (plastic sheet) between the foam and the final finished 4 inches concrete slab. The question is: Due to the fact that the heavily moistured sand and aggregate is sandwiched between the slab floor and the 4 inch insulation will they both dry out and can the moisture from the sand and aggregate cause rising damp on the concrete block walls?

Responses (3)

Frederick Beggy
Frederick Beggy June 12, 2022, 8:06 a.m.

Mr Reynolds thank you for your informative reply.

The reason for the sand is to ptotect the membrane from being punctured by the aggregate. 

I will follow you instruction.

Many thanks again

Frederick

Mike Reynolds June 14, 2022, 3:36 p.m.

Very happy to help Frederick, good luck with your project.