I know the best solution is to either have someone scabble up the bitumen or dig and re-lay the subfloor...however, given the cost of doing that is 2-3K plus the cost of putting a liquid applied DPM down after I've been searching for other options.
It seems I need to remove the bitumen in order to apply most liquid DPMs as it needs to adhere to avoid hydrostatic pressure forcing water up between the subfloor and the DPM and/or making its way to the walls or anywhere else it decides. The bitumen residue prevents most things adhering I guess.
So why wouldn't I just apply another (more modern) bitumen based DPM instead ? i.e have the marley tiles removed, clean up the subfloor without trying to remove the residue, then apply something like RIW Heviseal which is bitumen based so presumably compatible with the existing bitumen.
Then put an underlay with built-in DPM for added value over that before the engineered floor...
It seems I need to remove the bitumen in order to apply most liquid DPMs as it needs to adhere to avoid hydrostatic pressure forcing water up between the subfloor and the DPM and/or making its way to the walls or anywhere else it decides. The bitumen residue prevents most things adhering I guess.
So why wouldn't I just apply another (more modern) bitumen based DPM instead ? i.e have the marley tiles removed, clean up the subfloor without trying to remove the residue, then apply something like RIW Heviseal which is bitumen based so presumably compatible with the existing bitumen.
Then put an underlay with built-in DPM for added value over that before the engineered floor...
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