Waterproofing exterior wall below ground

[Sunbath]

Hi. I wonder what would be best to use to waterproof the exterior wall below ground level.



I have to dig up around almost all of the house for a cable and as we have permanently a problem with rising damp I thought it would be a good time to put a french drain pipe in and possibly tank the exterior wall as well. But I can not see which product would be best to use external and below ground.



A lot of videos I found show a product like Everbuild Black Jack Damp Proof Membrane , whilst it says on the product description just above ground. And then is the Everbuild Febtank Super Tanking Slurry for example?

What material would you use to waterproof the external wall please, costing not the world? And breathable I guess.

Thank you for your help and ideas.
Manfred

 

[^woody^]

You can't.

How are you going to water proof the other side of the wall? And the concrete the wall sits on?

 

[Sunbath]

Hmm, you think there is no point in any of those products to use?
From the inside where accessible I have already used injections. But in some areas is concrete put in, so I thought something must be there to protect the external wall more against water?

 

[^woody^]

From the inside where accessible I have already used injections

I meant the other side of the wall that is below ground under your floor.

Fact is, you can't waterproof a wall which is sitting in the ground agaist rising damp. You need to deal with rising damp via a horizontal barrier above the ground - physical barrier like a DPC course or injected barrier.

 

[Sunbath]

Thank you for your time and thoughts.
. Where possible I did this below the floorboard, but I have a large area where concrete is put down inside, replacing the floorboards, so I can not access it from there. I believe that the cavity of the extension wall is full of rubble/soil, as I saw this already before and tried to clear as much as accessible.

So I wonder if I can do anything else to keep the external walls more dry?

 

[foxhole]

Hi. I wonder what would be best to use to waterproof the exterior wall below ground level.



I have to dig up around almost all of the house for a cable and as we have permanently a problem with rising damp I thought it would be a good time to put a french drain pipe in and possibly tank the exterior wall as well. But I can not see which product would be best to use external and below ground.



A lot of videos I found show a product like Everbuild Black Jack Damp Proof Membrane , whilst it says on the product description just above ground. And then is the Everbuild Febtank Super Tanking Slurry for example?

What material would you use to waterproof the external wall please, costing not the world? And breathable I guess.

Thank you for your help and ideas.
Manfred

More likely you have penetrating damp, how far below the dpc is the current ground level.? Exterior photo’s?

 

[^woody^]

If you post some images of the situation you'll likely get some potential solutions to consider.

 

[Sunbath]

Hi. Thank you both for your replies.
Attached some pictures. The dpc is around 15cm above ground. But I just noticed that old pebbledash rendering is still on, below the ground soil level. So I guess this needs taking off too to reduce bridging, or?

 

[^woody^]

Yes, definitely. Run a grinder through it just below that new render line - and hopefully that is above the DPC line?

You could actually leave the render on as long as you cut a slot to separate it from the render above the DPC.

That alone may be the source of your problem.