Pyrite fixes has caused dampness in apartment

Hi,
I am writing this on behalf of my friend who is at her wits end and is seeking any advice on her situation. She is the owner of a property that was affected by pyrite and has many years of problems with it. She currently has tenants in her apartment as she has emigrated to Australia.
A couple of months ago the builders came to fixed the pyrite issue . The tenants had to move out for a month or so and have since moved back in when the issue was resolved. She has recently got emails and photos from her tenants saying that there is mould on their clothes and it has got really bad since the builders came in to fix the pyrite issue.
She has gotten an engineer in who has sent a report to the builder and she is waiting to hear back from them.
In the meantime the tenants are looking for compensation and also want to pay half of their rent because of the mould.
Who is liable here for the tenants damaged clothes and the mould in the apartment any advice on this please?
thanks

What did the engineer's report say?

How long are the tennants in there? Have they been ventilating/heating the place appropriately?

Well the tenants seem to be suffering, first they had to leave their home for a month, now they return and have a new problem with damp? In the first instance they have been very accommodating by leaving for the month so they sound ok. Maybe negotiate a reduced rent with them until the damp issue is resolved. It's the landlord's responsibility to sort out the tenant's. If as a result of the builders work they have cause her financial problems then presumably she can sue the builder but it would be far better if he came back and sorted out the issue pronto.

It's very strange though, fixing pyrite, meaning structural problems, now leads to damp.

Bronte said:

It's very strange though, fixing pyrite, meaning structural problems, now leads to damp.

Click to expand...

That's why I asked how long the tennants had been there for. I have heard many tales of people renting properties where the tennants are blocking vents, not using the heating much or at all, not using ventilation during cooking, etc., resulting in very significant damp/mould/health problems.

It could be that they damaged the damp course when correcting the pyrites issue.

I have had experience of this lately so maybe I can help. In my case it was in the main bedroom of the apt, where there had been no issue before. Pools of water forming on a windowsill of a french door and bad mould around the internal walls near the skirting boards. Underlying problem was that the vents on the windows had been inadvertently closed. These are small rectangular black boxes on the top of each window - built into the actual PVC. They are meant to be left open at all times to allow air to circulate. Before finding out I tried everything including purchasing a dehumidifier. The problem was moist air coming into the bedroom from the ensuite everytime someone had a shower. Even though the extractor fan was working in the ensuite it was insufficiently powerful to remove all the moist air in the room. You will have to treat any mould with a spray, readily available in any hardware shop, its quite strong and be careful not to breath any in when using it. I then painted over it. It has not recurred as the vents are now OPEN in the room ! I think people close them during the winter to prevent heat escape but its what causes the emergence of mould.

Unless the OP comes back with more details, all we can do is speculate.

The content of the engineer's report is key, only the OP knows what was in that.