Water ingress between concrete slab and blockwork

Built a shed over the summer. Concrete slab and then 3 course of blocks (rest was timber framed). The exterior of the blocks was clad with a slate cladding left over from another project.

Just noticed I have water seeping into the shed floor after all the rain we've had these past few days. It looks like the rain is pooling on the slab against the walls and then seeping underneath the blockwork into the shed. Probably due to my amateur blockwork and pointing.

I can't access the blockwork from the outside as it's been clad in slate. So trying to think of a solution for the interior blockwork. Wondering if something like this would do the job?

https://www.screwfix.com/p/sika-5-28kg/83502

Anybody used this? Or any other solutions come to mind? Thanks in advance.

This usually happens when the concrete base is exposed around the walls of the shed so rain falls on it. It will be worse if you have no eaves or gutter.

First check if this is happening, and how large the exposed part is. Lead the downpipe well away.

You may be able to add mortar or concrete with a slope to make the water run off away from the shed, and/or some kind of sloping cover, cladding or roof to prevent water falling on it.

The top of the concrete needs to be higher than the surrounding ground level or water will drain onto it. This may require a small trench, preferably filled with pebbles.

Does the concrete floor have a DPM?

JohnD said:

This usually happens when the concrete base is exposed around the walls of the shed so rain falls on it. It will be worse if you have no eaves or gutter.

First check if this is happening, and how large the exposed part is. Lead the downpipe well away.

You may be able to add mortar or concrete with a slope to make the water run off away from the shed, and/or some kind of sloping cover, cladding or roof to prevent water falling on it.

The top of the concrete needs to be higher than the surrounding ground level or water will drain onto it. This may require a small trench, preferably filled with pebbles.

Does the concrete floor have a DPM?

Click to expand...

Thanks. Yes you're right, the concrete base is exposed and there's no eaves or gutter. I neglected to put a DPM down.

The top of the base is higher than the surrounding ground level though so I guess what I could do is take a grinder to the exposed part of the concrete slab and just chamfer it so the water runs away. I would think that should solve it.