Damp Proof Membrane on possibly damp concrete floor...

[MrShed]

Hi all,

When I pulled up the old laminate (with poly underlay) from our kitchen, there was one significant damp patch underneath - at the time, I assumed this was due to a leak in the kitchen with the prior occupants appliances - the damp disappeared after a few hours. However, I now wonder if this is the case, and if in fact it is a case of light rising damp.

To make sure no issue, I am going to install a DPM before I put the new (tiled) floor in place. However, two main questions:

1) Will this not drive any damp issue up the walls (which currently have no issues)?
2) Is there any way the DPM can be laid without using screed/leveller on top? I am trying to avoid this due to timescale - can, for example, polystyrene board or backerboard not be used?

Thanks in advance!

 

[Alisdair]

find out if you have damp first! Put some plastic sheeting over the area that was damp and tape it down well, if you get condensation/damp under this after a few days you have a damp issue! A liquid DPC can be applied using a spiked roller. Then you have to prime it after i seem to remember, which is just rollering on some special primer, then lay your flooring on top - no need to latex over the top if you dont want to, also you only need to primer if you are latexing over the top. Easy job but not cheap if you get a good liquid DPC. Will it drive the damp up the walls - good question, I don't think there is an answer other than suck it and see. If that happens then you will need to inject a DPC