Wonder if anyone can help with this problem? Got called to look at a amtico job which has been down around 12 years. The floor was like sponge so took some up. Amtico on 4mm ply, on chipboard which is rotten with damp. Under the chipborad is polystyrene which is damp then I could see a blue dpm sheet which I think is on concrete. The building is in liverpool dock land. About 200 houses built there late 90s I have told the lady to contact the building company. Not sure what to do now or who i can call. Also There is no water damage under the kitchen units so no sign of a leak from sink or whites
floating chipboard floor. Construction should be - concrete base with DPM sheet below but sometimes ended up on top (should be below but loads of confusion back in the 90's!) DPM sheet used as vaporous barrier on top of concrete. (this was normally forgotten or the confusion be-gain as above ) Then a insulation at minimum of 75mm i think it used to be. next we have a floating chipboard floor glued together at tongue and groove. In the case you have i would say that dpm sheet was not installed or vaporous barrier missing. FIX- uplift and replace.
has the blue dpm failed ? if not moisture could have penetrated from side , damp test subfloor to see how damp it is?if dry must be from elsewhere
I've seen this before ingress from above. As with all floating floor installations the chipboard back in those days would not have been sealed at the perimiter with flanking strips or fire fill stop. If the polistyrene is wet and the plastic is wet on top it can only be ingress from above ie a washing machine leaking or dishwasher only needs to be a very slight weep from said fittings. It will drip onto floor finish then track under skirting were it can or under the units till it finds the gap at the wall junction and down onto the plastic then sucked up by polistyrene then the chipboard hence why its taken 12 years to show up. And that chipboard acts like wheatabix sucks it up and turns to mush jusy how I like my wheatabix mushy lovely.
Have you asked the care taker, if the building was recently flooded? I think you'll need to hire a water damage restorer to remove the moist and the molds.