Damp at base of walls

[Jordsocial]

Hi

I’ve recently had an independent damp survey on my home and they’ve mentioned that the external ground levels are too high and bridging the damp proof course. The recommendation was to lower the external ground level by digging a trench and fill it with gravel.

In the front of property there is what appears to be concrete footing right next to the base of the wall which would prevent me from digging a trench and in the back of the property it is a solid floor.

I have attached pictures for reference. The building has lime plaster internally and lime mortar between brickwork.

There was previously a cement plinth around the base of the walls which I have recently taken off.

I found a physical dpc on one wall in the back of the property but cant locate it on any other walls.

Any advice is appreciated?

Is lowering ground levels absolutely necessary or is there any alternative considering how difficult it could be?

Happy to give any extra info to help.

 

[eon]

I have a similar situation here. It's hard to tell from the photos but it looks like there was some previous chemical injection.
It's good to hear the surveyor didn't just recommend more of the same.

The vent looks like it is blocked. Is that a solid floor behind or is it suspended? If suspended then I would clear the vent and allow air to circulate throughout.
(Same goes for any vents where there is a suspended floor.)

I noticed the down pipe beside what I assume is a bay window? That doesn't look like it was draining away to anywhere.
Ideally it should be going to a drain or a soak away and not pooling beside your walls.

Are the concrete footings the base of your foundations? If so you might not have a choice but to run your trench along the edge of this. I would clear away all the debris and dirt and try to see if water will just sit on top of this or if it can drain off. Ideally you want it to drain away from the brickwork. If water is pooling here on top of the concrete you might look into adding a small mortar filet to make sure water runs off into your trench. I'm sure more experienced folks here will have more suggestions.

What kind of state is the external render in? Does it sound blown? Hollow when you tap it? Or does it seem very well bonded? I ask as this could be contributing to the damp too.

Search the forum for "zebcolm". This is a trench developed by two members here. Also take a look at the SPAB Control of Dampness technical advice note pdf.

I think it would be wise to go slowly with this and monitor how each incremental adjustment you make affects and hopefully improves the situation over time.

 

[a twig]

As much as a pain lowering the ground levels seems, it is 100% the easiest, cheapest and one of the most effective solution to any damp problems