Repairing floating floor after flood damage!

[neil5623]

Help,

We recently moved into a house to discover that there had been a water leak from a downstairs sink over many years.
(crap survey. lesson learnt)
The water had leaked onto the chipboard floating floor and built up underneath the lino in the kitchen.
The floor was completely ruined and a local builder replaced the damaged area or so I thought.

We have since had a full kitchen fitted but now part of the floor has started to sink by about 1 to 2cm and makes allot of creaking noises. I've brought up the laminate floor to discover a damp smell coming from the chipboard.

Beneath the wooden boards was a damp proof membrane which was on top of polystyrene sheets.

No dehumidifier was used in the first repair so I'm guessing there is still water trapped in there.

Will the polystyrene need replacing in the sunken area? I don't want to rip out the whole kitchen........not sure what to do for the best.

 

[tony1851]

why have they put a polythene membrane between the polystyrene and chipboard?
Is it a solid (concrete) floor underneath?

 

[neil5623]

Yes, beneath the polystyrene there is 4" of concrete and then another damp proof membrane.

I've been told now that since the floating floor was split for repair it has lost its structural strength and there are now areas of weakness hence the movement and the creaking.

The last builder who took a look didn't think there was any damp and said there was nothing more I could do as any more disturbance of the floating chipboard floor would weaken it further and cause the problem to spread throughout the gound floor of the house and possibly into other rooms!

Surely there has to be a solution I can't believe they are aloud to build houses this way!

 

[noseall]

A chipboard floating floor is an inexpensive way of producing a finished floor. Certainly not ideal for wet areas or areas of frequent pedestrian traffic.

However, it is a useful way to finish say a garage conversion whereby there is already a slab in place and tolerances are tight.

It is by no means a choice of floor specification that is widely used when building from scratch.

I would rip the lot out and lay celotex with 25mm ply floating on top, or look at using insulation and screed if tolerances allow. Bear in mind that you would need 75mm screed + insulation so it might not be practical.

 

[joe-90]

I agree with nosey. The cellotex route is a good 'un. It's insulation value will pay it off over the years.

 

[tony1851]

If the original leak had occurred over a long period, it is likely that the concrete would be very damp, even if the surface seemed dry when your first builder did the repair work. This will cause the recurring smell.
The only way to do this effectively is to expose as large an area of concrete sub-floor as you can, and let it dry thoroughly- this may take several weeks.
Then, reinstate the insulation and flooring. Moisture-resistant chipboard should always be used in kitchens and bathrooms.
Unfortunately. this type of floor is not ideal as it will 'give'and creak after a while, regardless of leaks. As a previous contributor suggested, a screed on top of the insulation is a better way, but that's expensive, v. disruptive, and will affect levels in the rest of the house. I think you are stuck with trying to make the best of what is basically a poor type of construction, but whatever you do with it, make sure the concrte is dry!.