Laying stone floor - do we need a dpm?

[zacha4]

Our house is an old 1850 sandstone cottage. The floor in living room originally was old sandstone flags laid directly on earth eg no dpm. It has been partially concreted so unable to return back to original flags so plan to lay a new sandstone flags on top.

When we moved in it was carpet on top of vinyl tiles, we removed the carpets and tiles and left with the original floor, in one corner it was slightly damp but this now has dried up.


With the new floor should I level the floor as its slightly uneven and also fit a dpm or leave the floor to breath naturally to stop driving damp into the walls.

Any help greatly appreciated

 

[zacha4]

Any help would be grateful

Thanks

 

[2929twin]

If its a habitable room, you should have a DPM. (Posting on this site for Liquid DPM). I would consider taking floor out complete and laying new concrete on DPM sheet then flag over for appearance.

 

[JohnD]

digging up the old one can also give more headroom than applying a third level of floor. It also will not crack along the old flags joints.

If you are digging it up you can also include sub-floor insulation which will make the room less cold.

 

[mac391]

It's a realy good point !! Sandstone flags that have been down maybe 150 years against modern DPM's?

Your current floor may well have outlasted most modern techniques but in reality it isn't breathing as such, it's just soaking up moisture from below, which would have escaped 100 years ago via poor draftproofing etc. and now will accumulate as condensation if draft proofing and insulation is up to standard.

Remove all of the old floor (maybe use it outside, patio or feature) Incorporate a DPM and lay new flags..