DPM damaged

25 Nov 2013
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United Kingdom
Hi Folks,

I wrote before about this however I have done some further investigation. I have had a damp problem in the bathroom since the day and hour I bought my current house. It was not noted on the survey because

1) The room was tanked
2) The walls had wallpaper on them

So any surveyor doing a cursory look would not have seen any damp.

I pulled back some concrete floor to find that the wall DPC laps a concrete sub floor and then A DPM was just loosely laid on-top of the dpc coming from the walls. Now normally this could be fine if there is no bridging of moisture

Here comes the shocker:

Whoever plumbed the extension prior to the final insulation + 100mm screed cut the dpm to make room for his pipes to run under the dpm. meaning the Pipes run with the dpm cut on either side of the pipe with the middle being pipe & insulation insulation e.g. ( [DPM] |PIPE| [ DPM ] )

I am thinking this will be a massive job pulling up a 13x13 foot room a 7x7 foot room and a 4 x 2 foot room to relay a new DPM.

Alot of website say to just tank the rooms with a waterpoof screed but what stops the moisture rising via the brickwork as obviously this new floor is above the old DPC and DPM. which met eachother on the subfloor.

100 mm screed
40 mm T&G Insulation
1200 DPM
100 mm Sub Floor Concrete
250 mm blinding.

Any advice here?
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