The marble floor you are describing most likely takes its water from joints. Typically the shower is separated and a membrane within the shower will take care of moisture toward the drain. Everything it seems points to how well the stone floor and joints are sealed. Over time the joints will deteriorate and moisture will penetrate below. Therefore, the only way I know to keep moisture at bay is to work all the joints and seal the entire floor properly including the shower. Care needs to be taken with the type of sealer used as some can discolor stone etc.
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Constantine Vasilios AIA
Principal
Constantine D. Vasilios & Associates, Ltd.
Chicago IL
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Original Message:
Sent: 10-28-2020 13:24
From: Stuart Berger
Subject: Waterproofing
I have a client with a second floor bathroom entirely finished in custom cut Carrera marble; floors, walls, ceilings. I discovered a slow leaking condition which is caused by the lack of waterproofing directly outside the shower extending to the area in front of and below the lavatories. (approximately 6 ft. by 3 ft.). The owner is adamant about retaining the stone. The marble floor cannot be matched due to color, quality and size. Is there a method for top down waterproofing without removing the floor stones?
Respectfully,
Stuart Martin Berger, AIA CSI-CCS
Director of Architecture