Damp and high external ground level (next to pavement/footway)

[Woodpecker2]

Recently had a damp survey on a property we’re purchasing, specifically went with an independent surveyor that had been recommended and who doesn’t advise DPC injections etc.
The property is 1800s stone and has no front garden, the front wall is straight onto the pavement outside. There is damp in the front walls, some condensation but also patchy cement mortar with gaps.

The report advises that whilst they rarely suggest this, as the ground level can’t be lowered at the front, they’d recommend tanking. My thinking is this is a no go?

Our plan is… repoint with lime, and focus on ventilation initially. See how dry we can get it. It’s also currently vacant so hoping that moving in, opening windows and heating will help a lot.

I’m assuming the council (?) wouldn’t allow us to dig a trench or lower the ground level on the pavement. What else could we consider?

 

[malcolm]

It probably is worth posting a photo. I guess is the wall is on the pavement there will be a door in it and the exterior ground levels will be similar to internal levels?

 

[Woodpecker2]

Hi Malcom - I’m a bit hesitant to post a photo (and tempt fate!) until purchase has gone through. But it’s exactly as you describe. Front door opens onto pavement at pretty much the same height. I’ll try and find a similar photo!

 

[Woodpecker2]

As an example (random cottage on google images!). Front door straight onto the pavement and at the same level. The front door timber is rotting from the bottom along with damp front walls.

 

[malcolm]

My front door also opens onto the pavement but I'm lucky and have a 3 inch step. It's not caused issues other than where the gutters out flowed onto the pavement. When the ground level inside and outside is the same it should be sufficient to have breathable walls - lime pointed outside and lime plastered inside at least on the bottom 12 inches of the walls. Tanking is not going to work and will only cause the wall to become wet, attract condensation, and eventually give you damp higher up the wall.

I had that where a wall had been tanked. On the other side of the wall the ground levels were maybe 12 inches higher but internal. Replacing the lower 18 inches of the plaster with lime seems to have fixed it, though it took about 2 years to dry out. I think there wasn't much water to deal with and it sorted itself out when it was allowed to evaporate away.

 

[alexander]

although you could tank it, it will not stop the water coming through the wall so you would still need a sump pump to get rid of the water externally,
you have the right idea take the wall back to the stone work repoint in lime mortar both externally and internally if required add, heat & ventilation internally let it dry, then re-plaster with lime plaster if required it may never be 100% dry completely but its probably the best you will get, as any water seepage will come through the wall internally if it can get out externally so heat and ventilation is important
the council will never allow a trench along the front of the property if its onto the street they continually hide behind health and safety as it would be seen as an accident waiting to happen & as the pavement is there responsibility its them that are sued.
good luck

 

[Woodpecker2]

Thank you - your thoughts are much appreciated and have given me lots to think about.