Fill the gap between exterior wall and ground

[terryt24]

I would like to hear people's advice on how or whether I fill the gap between external wall and ground as in the photos.

It is in my garden and I can see a layer of black thick sheet coming out from the gap, which I assume is DFC? There are lots of soil both above and underneath the sheet and weeds grow crazy there. I have now cleared all the weeds and wonder whether it is ok to use some sealant to fill this gap?

I read online some people mentioned about sika Polyurethane sealant. And someone says the gap should be left there for expansion. And some say it is for water to leave and avoid damp.

I am quite confused whether it is sealable? And if yes, which material should be used? If not, what would be the best way to prevent weed growing in this place?

Thanks for any suggestion.

 

[JohnD]

Stand back and take a wider pic. I thought at first it was a deliberate expansion gap, but I think perhaps the concrete has settled. Is there a drain nearby?

 

[Deluks]

Is this your house, or a garden wall?

Picture taken further away would help.

If you are trying to figure out a foolproof way to prevent weeds, forget it.

 

[terryt24]

Stand back and take a wider pic. I thought at first it was a deliberate expansion gap, but I think perhaps the concrete has settled. Is there a drain nearby?

Hi, here are the photos. There is no obvious drain nearby. The only thing is gaps between slabs and the garden soil nearby.

 

[terryt24]

Is this your house, or a garden wall?

Picture taken further away would help.

If you are trying to figure out a foolproof way to prevent weeds, forget it.

Yes, it is my house wall.

 

[JohnD]

I can't see any concrete clinging to the wall so I think it must be an expansion gap. Not very smooth though. If you want to fill it you will need something flexible, after cleaning it out. Expanding foam will do but degrades in sunlight you you would need to cap it with a silicone or similar seal.

DPM is unusual. I once laid a patio slab with brick shuttering and DPM in case I later decided to put a conservatory or something on it. It did keep drier and cleaner with no moss or mould.