Damp Along Edges of Concrete Shed Floor Damp can be a major issue in the home. Find answers to questions or post your own here.

[Chris-J]

There's damp along both edges of my concrete shed floor. No moisture, not actually wet to the touch, just damp. We used DPM, both under the entire floor, which we poured concrete over and also under the footings.

There's a slight issue with rainfall not completely draining away outside, but I'm already skimming the turf off because the ground there does look a tiny bit raised. Hopefully, that will help a bit.

I've done a bit of a search on the forums and I read that painting bitumen will seal and solve the issue.

Would that be the way to go? We've had crazy rainfall the last week and I assume that some damp is expected. But all the same, I'd like to sort it out before things get worse.

[thedoctor]

Hi

The water is getting in between the top of the slab and the underside of the first course of blocks. The DPC stops water moving vertically, not horizontally. The bed joint soaks up water that lands on the external section of the slab and it is transferred through the mortar, inside. This doesn’t happen on other joints as gravity keeps the water moving down the face of the blocks.

Concrete a small triangular fillet around the wall perimeter where the wall meets the base so, as the water runs down the wall, it hits the fillet and is steered away from the wall.

Hope this helps

[Chris-J]

Thank you for the advice

Much appreciated.

[Chris-J]

Do you mean like this:

[img][img]https://i.imgur.com/YSAjOr8.png[/img][/img]

Would the position of the fillet above solve the problem or does it need to be flush with the base of the external block?