Ground level raised above DPC in Edwardian terrrace

[maznaz]

HI there. I've bought a house which is an Edwardian terrace with a cellar. The rear is a full storey higher ground than the front, due to being on a large hill. COnsequently there's a lot of groundwater moving through the general area and the back of the house is quite damp. The rear room has no cellar below and has a suspended timber floor.

 

I took the floor up in the dampest corner and found a few potential issues. There was almost no sub-floor ventilation as it's full of rubble with one air brick and seemingly no through ventilation to the cellar. But also, there is a clear DPC running about half a brick below the height of the external concreted floor.

 

I've had a surveyor and a structural engineer for various reasons take a look at the place and neither of them seemed that fussed about the DPC being below ground level, but from my research that's a clear and likely source of damp ingress. 

 

We run a dehumidifer constantly to see if it will dry out with the boards up and although it keeps the damp smell at bay, the water keeps coming and the dehumidifier fills its reservoir daily.

 

In order to try and improve things I'll be taking out a load of rubble and making a good cross-ventilated sub-floor, but am I fighting a losing battle if I don't sort out the ground level? I have two walls both external in that room and both are raised above the DPC. One was done by the previous owners and one is sadly a shared passage between houses that was renovated by the neighbour without gaining consent.

[markc]

Ground level raised above DPC will definitely encourage damp. Getting some underfloor ventilation going will certainly help and go a long way to getting rid of the musty smell but you really need to look at lowering the external floor level,

[maznaz]

11 hours ago, markc said:

Ground level raised above DPC will definitely encourage damp. Getting some underfloor ventilation going will certainly help and go a long way to getting rid of the musty smell but you really need to look at lowering the external floor level,

Thanks that’s what I was afraid of but it makes sense. I have no idea what to do with regards to the shared passage though. Given that the work was done without notifying the previous owner an I within my rights to expect the neighbour to rectify it? Or is it all too late?

[markc]

@maznaz I reckon you have little to no chance of the culprit making the remedial works.

in your own interest I would bite the billet and get on with it. While the path is up put some drainage in if possible and take water away from the walls

[maznaz]

22 minutes ago, markc said:

@maznaz I reckon you have little to no chance of the culprit making the remedial works.

in your own interest I would bite the billet and get on with it. While the path is up put some drainage in if possible and take water away from the walls

Cheers, this sounds sensible. I have additional complications with a shared drain running down that passageway but I can at the very least cut away a piece to lower the level below my dpc and put pea shingle in or something. I'd love to be able to put in a proper drainage system that would divert water around the cellar though!