Window reveal damp - rendering ??

[Fred101]

Hi All,

Hoping some kind soul can offer some guidance please.
My daughter has a victorian terrace groundfloor flat in south London, but has recently noticed a small damp patch on her wall by her patio doors (see attached photos). Upon checking outside it's clear that a chunk of the render that runs around the whole outside of the terrace at floor to wall level has come away and so I am presuming that this combined with the brickwork mortar degradation in that same area is what is creating the damp problem. I have no issue repairing the brick mortar with lime, but am unsure about the external rendering as this appears to be in 2 layers. It's also not soft and crumbly and so I don't believe that it is lime. So, I have 3 q's as follows:

1) If I repair the lime mortar first, how long should I then leave it before also replacing the missing render?
2) Any ideas what that 2 layer render is....would it be just concrete?
3) If its concrete, why would it be applied in 2 layers?

She has been trying to get someone interested to fix this but has been passed around......"you need a builder", "you need a renderer" but then no-one is responding to her request.....I'm guessing this is because it is a relatively small job and so thanks in advance for any help/guidance anyone can provide.

Cheers,
Freddie.

 

[Notch7]

floor to wall level has come away and so I am presuming that this combined with the brickwork mortar degradation in that same area is what is creating the damp problem

I wouldnt say it necessarily connected

I think it is more likely that the detailing of the vertical DPC up the door reveal is incorrect and the internal plaster is touching the external brickwork

In regards to the rendered plinth detail -it looks like it bridges the DPC which isnt great

 

[Fred101]

Thanks for the input. I don’t know whether this would have changed your response or not…..but my daughters flat renovation was completed Q4 2022 and so it went through most of last winter with no signs of a problem. So, if the DPC up the patio door reveal was fitted incorrectly wouldn’t that have shown up much earlier?
The only other change has been the loss of the rendering as shown in the pictures and so that’s why I was focused on that as the potential source.

 

[DiyNutJob]

There's what appears to be a hole top left of the first photo. Maybe water is going in from that? To find out what render used, maybe send photo to the people who did the rennovation and ask them?

 

[Odds]

Could the area beneath the door be repaired using a upvc skirting?

 

[Notch7]

Thanks for the input. I don’t know whether this would have changed your response or not…..but my daughters flat renovation was completed Q4 2022 and so it went through most of last winter with no signs of a problem. So, if the DPC up the patio door reveal was fitted incorrectly wouldn’t that have shown up much earlier?

no not necessarily in my experience

sometimes nothing happens for along time, then suddenly with the wind in a certain direction damp penetrates

The only other change has been the loss of the rendering as shown in the pictures and so that’s why I was focused on that as the potential source.

its certainly possible that could be the cause, although I wouldve expected the damp to be at the bottom corner

 

[foxhole]

Had similar damp next to a front door , but was caused by gutter leak soaking thru to ground floor and causing a small damp patch and effervescence .
Any pics above door to roof level .