Best way to install DPM on existing concrete floor

[Herman heckinsale]

Evening all,

Happy new year, so I need to create a DPM on my concrete floor as I don’t have one, I currently have bitumen on my floor which is a nightmare to remove and vet speradic and wanted to see if anyone could advise a tried and tested method for this scenario, my finished floor will either be LVT or engineered wood. Removing the floor is not an option.

 

[^woody^]

More bitumen!

 

[MisterBoy]

You could lay a simple plastic DPM and add another layer of concrete/self leveling if you can lose the height.
Although I'm wondering what would be so bad simply laying the plastic sheet directly under your underlay, maybe I'm missing the obvious but as long as you don't damage the dpm shouldn't that still achieve the same aim?

 

[^woody^]

You could lay a simple plastic DPM and add another layer of concrete/self leveling if you can lose the height.
Although I'm wondering what would be so bad simply laying the plastic sheet directly under your underlay, maybe I'm missing the obvious but as long as you don't damage the dpm shouldn't that still achieve the same aim?

Unlikely room for screed on the polythene.

Problem with polythene on its own is the risk of small air gaps between the polythene sheet and the bitumen surface and then interstitial condensation which could collect and move sideways and in extreme cases will be like a puddle under the boards and you could hear it move when walking on the floor. Same thing with the silver foil membrane that is sold with floor boarding.

It really needs another liquid coating.

 

[mikeey84]

There is a sticky on the flooring forum that deals with this question