Is this a plumbing issue?

[Paddydog52]

Hi all, black bits have appeared under kitchen and toilet flooring over the last few months, please see images, I’m wondering if this is actually a plumbing related issue in peoples opinion/experience? When I lift the flooring up and put newspaper underneath it becomes very wet.

 

[Chuck]

AFAIK, stone tiles have to be laid on a dry floor and it seems like this has not the case.

My guess is that there is a missing/faulty damp-proof membrane in the floor construction. This is alone might be enough to explain the damage to the tiles. A leaking buried water pipe or a leaking/collapsed drain will saturate the ground with water and make the damage worse or happen faster.

You may be able to detect a leaking buried pipe by making sure that no water is being used in the house and watching the water meter carefully. A drain pressure test / camera survey may add useful information. Either way, I'd expect the floor is going to have to be dug up and relaid in a proper manner with a correctly installed DPM, etc.

Do you have any construction records? (Plans, photos, invoices, etc.) If so, these would be a good place to start.

 

[Paddydog52]

AFAIK, stone tiles have to be laid on a dry floor and it seems like this has not the case.

My guess is that there is a missing/faulty damp-proof membrane in the floor construction. This is alone might be enough to explain the damage to the tiles. A leaking buried water pipe or a leaking/collapsed drain will saturate the ground with water and make the damage worse or happen faster.

You may be able to detect a leaking buried pipe by making sure that no water is being used in the house and watching the water meter carefully. A drain pressure test / camera survey may add useful information. Either way, I'd expect the floor is going to have to be dug up and relaid in a proper manner with a correctly installed DPM, etc.

Do you have any construction records? (Plans, photos, invoices, etc.) If so, these would be a good place to start.

Ok thanks for your feedback, moved in 8 years ago, the house was built over 50 years ago so it’s very old flooring and the tiles underneath the flooring is also 50 years old so definitely needs to be looked at after all this time. Don’t have any records with regards to the construction unfortunately.

 

[Chuck]

Hmm, maybe the source of the water is above the DPM. Do you have washing / dishwasher machine(s)? Sometimes a hidden leak, e.g. from a loose hose connection, can drip onto the floor, find a path to get under the the floor covering and spread under the floor from there. Check under the sink(s) and around the toilet, etc.

 

[Paddydog52]

Hmm, maybe the source of the water is above the DPM. Do you have washing / dishwasher machine(s)? Sometimes a hidden leak, e.g. from a loose hose connection, can drip onto the floor, find a path to get under the the floor covering and spread under the floor from there. Check under the sink(s) and around the toilet, etc.

Yes, we do have a washing machine and a tumble dryer nearby so that may be worth checking for leaks. Thanks