Damp wall at one end of an old limey kitchen

[Gelf]

We've had a problem with damp in our kitchen cupboards since we moved in. Only against one of the external walls.

This is a single story outshoot from a sandstone building (I would say extension, but all the houses have them so I suspect they were built with them) The outshoot is brick and lime mortar.

When we moved in there was sand and cement roughcasting on the external wall which had come away from the brick in places. I suspected that water was getting trapped behind this.
The roughcasting was sound on the other walls.

Last year we had someone come and strip the walls and re-render in thermocromex, which should be breathable, although he used a sand and cement scratchcoat, which he assured me wouldn't stop the wall breathing.

In between stripping the old roughcasting and applying new render it rained, alot (Scotland, summer).

The problem still seems to be there, the cupboards are smelly, it is worse on a hot day with the sun on that wall.

I got a cheap humidity meter and left in the cupboards overnight and was reading around 80% I also did the same under the cupboards also 80%

I Managed to remove a cupboard and the plaster underneath was soft, like clay in places. It seemed localised to the cupboard that I removed fortunately. So I stripped off as much plaster as I could. The plaster at the edges of where I could reach to strip it off is feeling dry (pic)

On the outside of the wall there is a patio against the wall, at the same level as the internal floor (pic). This raised patio is only against the damp wall the other wall has a lower patio against it. There is also a cast iron drainpipe going into the patio with a blocked off T at ground level (pic)

I have only just stripped the plaster, so I'm hoping that the wall will dry out, and the damp will go away, but I wanted to ask if there was anything I could do to help eradicate the problem?
We don't want to rip out the kitchen as it is only a few years ole and removing any other cupboards would probably damage the worktop.

some questions:

1) Will the sand and cement scratch coat really be breathable? I guess it was scratched down to the brick, but probably still not ideal. View attachment 143329
2) Could the wall still be damp from last years rain and previous dampness and simply just hasn't dried yet?
2) Can I just leave the wall bare (as it will be be behind the cupboard) or do I need to cover it?
3) Should I cut a trench at the join of the patio and wall to fill with gravel to aid drainage?
3b) If so I imagine the wall will be exposed, what to do with the wall below the gravel level
4) Is there any tanking or treatment that I might put on the inside to help?
5) I've assumed the damp is coming from the outside, could it be condensation trapped in the plaster?
6) Any other advice?

Thanks,

Pete

 

[bobasd]

is the floor a suspended floor?

probly bst to pull all the base units from that wall and hack off all the remaining plaser.it looke like gypsum plaster which is badnews .
and injection holes from a failed chemical dpc can be seen.
rising damp and condensation in the wall are probly happenin along the wall.

the back box should be replaced with a plastic box if a elec outlets needed..

the thermocromex site says the stuff is lime based andcan be layered on. so the s and c scratch coat is a barrier causing condensation in the wall.
ther should be a bellcast at the bottom of the render and the render should be stopped 150mm above any ground contact or above any dpc.
your solid wall brick mortar is sodden it wont be local.
removing the high patio flags will help to stop bridging,the ones near the wall.

is that CI pipe down pipe or a soil pipe? wheres the nearest manhole?
whats the grey plastic pipe near the ci pipe doing?

 

[Gelf]

Thanks for your reply Bob,

The pipe is an old soil pipe I guess, there's no gutter attached and it goes above the roofline like a vent, no idea what it was originally for. The grey pipe connecting to it is a lagged condensate pipe from the boiler. That's the only connection now.

I can probably get most of the plaster off inside, but I can't move the cupboards as the worktop is supported by them, so I'll need to poke around in the gap behind them.

I'm not sure I want to remove the render as the walls weren't in could nick last time, but maybe I could get the lower 150mm cot back and a skew put on, do you think removing the plaster and taking it the patio would fix the problem? Maybe with a vent so the wall could dry from the inside?

 

[bobasd]

gelf, i asked a few questions to try to help you?still dont have all the answers.

 

[Gelf]

Sorry, was late.

Floor is solid, looks like a dpm on it.

CI pipe goes underground then joins a vertical ground drain about 1.5m away. I.e I can pour water into top of pipe and see it flowing into vertical drain. There is a manhole a further 2m away, but the drain pipe (now whole house) is covered.

 

[Mr Chibs]

Agree with previous comments, I would hack off 150mm of the new render (sorry) and either lower the patio or at least cut it back 200mm from the wall, dig a small trench, fill with pebbles... presume there is now DPC, but the ground level looks high, can you post a pic of the 'outside'.

 

[Gelf]

A couple of pics with more in field of view, can see the step and vertical drain.

Tbh the render didn't go on as well as I'd hoped, so will need painted with a lime paint.

 

[bobasd]

so your on a hillside which will give you water table pressure problems anyway.
definitely lower flags near wall to gulley level.
where does the gulley drain to?
you could probly drop the CI pipe an make other arrangements for the condensate pipe.
presume your WC is located somewgere else in house.
wheres the down pipe for the guttering?

 

[Gelf]

It is part of the main drain to the property,

The down pipe for the gutter is off to the left, the kitchen waste also goes into that down pipe.

The rest of the house's waste pipes also join at another gully drain, about 2m to the left of the one shown, then it all goes into the one shown, and away to the sewer. The horizontal pipe is 2-3m underground.

I expect that the bricks under any hacked off render will now be in poor condition. Anything I can do with them? Aside from repoint in lime.

Btw, thanks everyone for replying, really appreciate it