Overflow leaking pipes causing sever damp in my flat

Maintenance

Hi. I have a flat and there is a serious damp issue in the bathroom with the walls saturated and there is extrme mould on the walls.

I have had a report identifying the problem which attributes it to a number of overflow pipes from other flats in the block which have been leaking for considerable time.

The insurance company agrees that they need confirmation that the overflow pipes are all fixed and no longer leaking.

The managing agent is saying it is not their problem to get the other flats to fix the pipes. Although they are responsible for maintaining the structure of the building.

I do not have the contact details of all the flats in the blocks - some are let and I believe some a owner occupied

1. Is it is the managing agents responsibility to get the leaking overflow pipes fixed?
2. What can I say to the managing agent so that they swiftly fix it as the damn problem is severe and do not fob me off - ie is there any legal obligation they are under?