Damp/lower ground level query

[mackintosh]

Hi, looking for advice. I’m currently in the process of buying a 4 storey victorian terrace in West Yorkshire built on a hill.

Essentially the front of the house is underground at LG level - there is a store cupboard and a toilet which are very wet and uninhabitable as they are seemingly “outdoors” due to a street level grate that has been poorly covered with a pvc window. There is foliage and water marks down the walls as a result and with minimal ventilation (hope that makes sense, and presumably there is plenty of moisture from the surrounding ground.)

To the rear, the LG is actually above ground and is where the kitchen is. It has an open chimney breast, a window and a large door back door.

The survey has suggested tanking/drainage the entirety of the lower ground but I understand this can be detrimental in period properties with lime mortar and stone brickwork and we’ve been quoted an astronomical sum.

In an ideal world, we would make the toilet and store cupboard usable, but I am utterly lost as what can be done, what the right thing to do and where the whole lower ground needs the same treatment or whether we can apply intervention to the toilet/store cupboard only.

Utterly lost and would welcome advice. Let me know if none of this makes sense and i’ll do my best to clarify. I will also post some pictures of the area and layout. Thank you!

 

[erikwoolf]

We had the same issue. Front essentially LG below street level. In our case it is below the front garden. Rear is above ground.

The area was closed off from the rest of the house via a door and used to be a coal hole.

We ended up digging up the garden and externally tanking including installing a membrane and a French drain. From the photos in your case it looks like digging might be less of an option. We used Diathonite internally in the area and have installed a fan that runs continuously. So far it has worked well and even with all the wet weather we had we don't seem to have any damp.

Obviously you need to do something with the water that runs down from the street level grate and that probably requires installing a new cover(?) and managing the slope so water runs away from the top of that room. It then depends on how much you can manage humidity with improving ventilation only if tanking externally or internally is not a solution. How much in a hurry are you to find a final solution? You can in theory do it in steps improve water ingress and humidity levels first and if this fails consider tanking options most likely internally?

 

[erikwoolf]

You can see some of the issues we had and relevant responses here. Thread 'External drainage' https://www.periodproperty.co.uk/forum/threads/external-drainage.17869/

 

[mackintosh]

We had the same issue. Front essentially LG below street level. In our case it is below the front garden. Rear is above ground.

The area was closed off from the rest of the house via a door and used to be a coal hole.

We ended up digging up the garden and externally tanking including installing a membrane and a French drain. From the photos in your case it looks like digging might be less of an option. We used Diathonite internally in the area and have installed a fan that runs continuously. So far it has worked well and even with all the wet weather we had we don't seem to have any damp.

Obviously you need to do something with the water that runs down from the street level grate and that probably requires installing a new cover(?) and managing the slope so water runs away from the top of that room. It then depends on how much you can manage humidity with improving ventilation only if tanking externally or internally is not a solution. How much in a hurry are you to find a final solution? You can in theory do it in steps improve water ingress and humidity levels first and if this fails consider tanking options most likely internally?

Thanks this is super helpful. We were planning to throw our refurb budget into the kitchen and other LG level spaces once we move in. However, we are minded to try and control the humidity/ventilation/temp to see how the rest of the space fares. Obviously the toilet/coal store needs a different approach re drainage and water. We just want to avoid destroying the rest of the LG as much of it is original. Totally lost!

 

[SamB]

Hi, looking for advice. I’m currently in the process of buying a 4 storey victorian terrace in West Yorkshire built on a hill.

Essentially the front of the house is underground at LG level - there is a store cupboard and a toilet which are very wet and uninhabitable as they are seemingly “outdoors” due to a street level grate that has been poorly covered with a pvc window. There is foliage and water marks down the walls as a result and with minimal ventilation (hope that makes sense, and presumably there is plenty of moisture from the surrounding ground.)

To the rear, the LG is actually above ground and is where the kitchen is. It has an open chimney breast, a window and a large door back door.

The survey has suggested tanking/drainage the entirety of the lower ground but I understand this can be detrimental in period properties with lime mortar and stone brickwork and we’ve been quoted an astronomical sum.

In an ideal world, we would make the toilet and store cupboard usable, but I am utterly lost as what can be done, what the right thing to do and where the whole lower ground needs the same treatment or whether we can apply intervention to the toilet/store cupboard only.

Utterly lost and would welcome advice. Let me know if none of this makes sense and i’ll do my best to clarify. I will also post some pictures of the area and layout. Thank you!

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Slightly confused by the layout as the first picture looking in the door seems to have a bricked up fireplace at the right. Also is the thing cutoff at the right of the outdoor picture a bollard or possibly a vent pipe?
Obviously the first thing to do is stop the ingress with a properly sloped and sealed window or similar plastic right along the top, which will start giving you an idea how much moisture is coming through the wall. Does the toilet drain go down ? I assume this used to be open to the sky and the toilet drain used to drain the tiny yard.

 

[mackintosh]

Slightly confused by the layout as the first picture looking in the door seems to have a bricked up fireplace at the right. Also is the thing cutoff at the right of the outdoor picture a bollard or possibly a vent pipe?
Obviously the first thing to do is stop the ingress with a properly sloped and sealed window or similar plastic right along the top, which will start giving you an idea how much moisture is coming through the wall. Does the toilet drain go down ? I assume this used to be open to the sky and the toilet drain used to drain the tiny yard.

I don’t think that’s a fireplace - it’s on the external wall. Wondered if it’s an old coal hole but no idea. The bollard is a cast iron street lamp owned by the council.

The ingress from street level definitely needs sorting - but i’m concerned about ventilation. On the toilet floor directly underneath the grate, there appears to be a circle drain grate - presumably to drain away any water that makes its way in - i have no idea if this is original (it looks like a later addition).

I think addressing the ingress from street level is an urgent priority - alongside some kind of mechanical ventilation system. But then that still leaves high damp level readings in the dining room and kitchen - although this could be a result of the house being empty and the weather being so poor. Guess I need an expert…

 

[Stevers]

Can't help feeling that it's a small space that wasn't ever intended to be enclosed. You might need to embrace it as a bit of outdoors, perhaps with a glass canopy over to keep the worst of the rain out. It's really a light well, and once ventilated and sheltered there might be things other than coal that could be stored in there.

 

[Drayton]

My initial reaction is the same as Stevers - having looked at the interior photos I was very suprised by the external one.

I'd expect that to be outside space to let light in, not part of the house itself. I have a much smaller one - no chance of using mine for anything - and it has a drain to take away the water that accumulates as the top is just a grating.

Are there any similar houses on the street or in the area?