Damp help

[Steven963]

Hello
I am having a nightmare with damp I am sure it's penetrating damp. It is on the bottom course of bricks inside. I have removed the paving slabs from the external wall as these were too high and bridging the DPM.
Upon doing this it has revealed some sort of concrete mystery to me, it looks like it's rendered from matching the DPM down 2 courses of bricks then comes out by about a foot away from the wall. So like a slope for running water under the paving slabs. But I have removed a small section and under it is sand which is soaking wet. I hope somebody has an idea what this
Thanks

 

[vinn]

Remedial work has been done in the past with a little pointing and what looks like a fillet (triangle shape) of sand & cement. The air brick is a modern insert.
Maybe you mean DPC not membrane?

Is that a failed render or some past paint job on the bricks?
Is the inside floor suspended?
Is the wall solid or cavity?

If you stood back and took some more outside photos of the patio/wall elevation, and photos of the interior damp it would help?

 

[Steven963]

In the second picture you can see the black membrane it sticks out of the wall.
The bricks have been painted before but it is all flaking and coming off.
The affected wall has a solid concrete floor inside.
I think it's a cavity wall I cannot see air bricks Inside.
I'll take some pics now

 

[Steven963]

 

[Steven963]

Them pics ok?

 

[vinn]

Thanks for the photos.
The path to wall abutment is a curious arrangement in that it appears to have been copied from an asphalt roof abutment finish.
I say that because:
Thick bitumen or asphalt seems to have been overlaid on the path, & where the bitumen goes up the wall its been shaped in a cove, and in places has a sand and cement fillet.
The black "paint" is actually liquid bitumen.
These measures were probably taken in hope of remedying internal damp problems. They've not worked.
There's also what seems to be concrete (edging?) peeping out of the bitumen?


Anyway you would be best to remove all the cove business back to bare brick from ground level up about 150mm - like you can see in the corner behind the waste pipe.
Is there no gulley for that pipe to discharge into?
And scrape off the black paint - its possibly trapping moisture in the brickwork.

Roughly speaking: you have ground level to interior FFL problems, and if it is a cavity wall there's perhaps cavity bridging from rubble in the cavity. The cove effect could be bridging any DPC in the wall.

 

[vinn]

I've split my reply.
Why has an airbrick been inserted when you have a solid floor?
What is the black ABS pipe discharging from - a washing machine?
How high above ground level is the floor in the photos?
The quarry tiles show damp & the wall paper appears to be loose (& damp?). But you probably know this. Do you know how high the damp goes up the wall?
Is there a membrane below the slab?
Does interior damp run the whole length of that gable wall?

 

[Steven963]

Thanks for your reply.
The pipe is the condensate pipe from the boiler as there is no drain nearby, we haven't been in the house long.
The damp goes up about 1 brick and it is all the way along that wall.
Will the quarry tiles be getting damp from that wall?
I couldn't tell you if there's a membrane under the concrete but I can see one from the bricks outside.

 

[Nige F]

That condensate pipe goes into a rainwater downpipe that then just discharges on the white stones in front of the shovel ? That's where all the water is coming from along the side of the house - off the roof.

 

[Steven963]

No it doesn't go into a rainwater pipe it's just a pipe from the boiler. The rainwater pipe discharges into a grid on the other side of the building.

 

[Steven963]

So should I just remove the concrete and dig down 150mm?
Will I then be OK to relay the slabs?
Also how long should I take to dry out internally
Thanks

 

[vinn]

I've advised you above about some of what needs doing.
You might also dig out say 150mm below the surface you have now exposed and fill with stones, being cautious about the fence post footings.

This should allow rainfall to drain away. Its by no means a great solution but there's no possibility of a proper French drain from what I can see. Where would it drain to?
You wont be able to reinstate the paving unless its much lower, and slanted to discharge away from the wall.
Anyway, you could experiment?

Its possible that the partially rendered gable was applied in hope of dealing with damp or condensation.

The best practice solution for the interior would be to, in the absence of a membrane under the concrete, to carefully check the walls for damp or salts.
Short of lifting the quarry tiles, applying a liquid tanking and re-tiling, there's not much to be done if moisture is rising from below.