Flooring and Carpeting/Marble leaking watery substance through Grout
QUESTION: "We are moving into a rental home and we noticed a goo / watery substance coming out through the grout lines. Should we be concerned? Will the marble tile have to be taken out or can it be left alone? What could be the problem? We think the tile- layer may have used mastic as the adhesive. The watery substance smells like vinegar when rubbed on finger tips. The watery substance is only found in the family room and not anywhere else through the house. The bathrooms also do not show any signs of water coming through the grout."
ANSWER: This looks like mineral deposits. That is a sign of water in the foundation. It is common but will eventually damage, or may have already damaged the floor. The probable reason it has not been dealt with is because the most expedient way to remove this is an acid cleaner. Let me be very clear, DO NOT USE an acid cleaner, it will destroy the stone.
The landlord needs to find and eliminate the water seepage before any cleaning can be effective anyways. For the time being just get used to idea of wiping it up periodically.
Sorry this is not more conclusive, but having no idea the source of the water makes it tough for me to get a good solution. Good luck.
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QUESTION: I forgot to mention that there has been extensive examining of the pipes & plumbing, everything has come out clear. Would this still indicate an issue with the foundation? Also, should we just move on and look for another home or would we be able to move into this home at all?
In my experience this is an indication of seepage under the slab. This is normal and very difficult to be rid of as it is a water table issue. I guess that you will have to decide if the issue with the minerals in the grout will be an issue for you. Eventually this will break down most grouts and leave gaps and broken pieces of grout, but who knows how long a process that could be. Also, if the landlord is aware of it and you have made it clear that you observed it then they are responsible to maintain this and ensure it is dealt with in an expediant manner.
It is up to you guys, but this could be a potential hard spot between you and the landlord.