Damp. Seems too high for rising damp?

[Harry Bloomfield]

What do you mean? I've stuck a damp meter into it and unfortunately it shoots right off the scale.
Do you mean that it is absorbing moisture from the atmosphere?

Ask if you can check next doors wall for damp with your meter.

Might the scim have gone behind the skirting to bridge the DPC?

 

[^woody^]

Interesting. I'll look into that one. Thanks

I would not bother, as its new plaster and clearly an absorption or drying pattern, not random salts patches.

 

[^woody^]

Are you ventilating the room?

 

[jeds]

Most likely the wall is slightly damp due to years of cooking and condensation. You didn't notice it before because your original skim would have had a high lime content, which has a high tolerance of moisture. Gypsum plaster has zero tolerance of moisture.

 

[RrogerD]

Most likely the wall is slightly damp due to years of cooking and condensation. You didn't notice it before because your original skim would have had a high lime content, which has a high tolerance of moisture. Gypsum plaster has zero tolerance of moisture.

So you're saying to just leave it and it will dry out eventually?

 

[cdbe]

That's clearly damp. Your house is either built directly against the original external wall of the adjoining house or with a single skin wall against it. If there was a dpc in your neighbours original wall it's been breached by your house being built against it. Work next door may have involved removing old lime plaster which would have let the wall breathe. It was probably always a bit damp - covered up by some wallpaper or a few coats of eggshell paint.

I know it's easier to say than do, but don't take any chances, get the entire wall stripped back, tanked and rendered with sand/cement and waterproofer. I made the mistake of ignoring a similar situation a few year ago - even worse because I fitted a kitchen on the wall, only a lot of messing about with external ventilation has managed to keep it under control.

 

[jeds]

So you're saying to just leave it and it will dry out eventually?

I would properly investigate the wall for structural dampness, either by deep probe or a carbide test, and decide when you know the results of that. You might as well also test for soluble salts while you're there. If you leave it there is a chance it may dry out over time but it could be a long time and may not actually dry out at all. Probably best to bite the bullet now while you have it all exposed.

PS, electric moisture meters with pins on the wall will tell you nothing useful in this situation.

 

[drpepe]

That's clearly damp. Your house is either built directly against the original external wall of the adjoining house or with a single skin wall against it. If there was a dpc in your neighbours original wall it's been breached by your house being built against it. Work next door may have involved removing old lime plaster which would have let the wall breathe. It was probably always a bit damp - covered up by some wallpaper or a few coats of eggshell paint.

I know it's easier to say than do, but don't take any chances, get the entire wall stripped back, tanked and rendered with sand/cement and waterproofer. I made the mistake of ignoring a similar situation a few year ago - even worse because I fitted a kitchen on the wall, only a lot of messing about with external ventilation has managed to keep it under control.

OPs damp pics look v similar to our old place.

we had a similar situation in our last house, our ‘semi’ had become a terrace about 80 years ago, the newly built attached house next door was built on higher ground with apparently little thought of the dpc details. No amount of exposing or ventilation helped so we tanked it and it was fine.

Not a cure but it fixed the symptoms.

 

[RrogerD]

Are you ventilating the room?

Yep, fully vented. The other walls have dried out nicely.

 

[RrogerD]

OPs damp pics look v similar to our old place.

we had a similar situation in our last house, our ‘semi’ had become a terrace about 80 years ago, the newly built attached house next door was built on higher ground with apparently little thought of the dpc details. No amount of exposing or ventilation helped so we tanked it and it was fine.

Not a cure but it fixed the symptoms.

This is interesting.

The adjacent building was originally I believe, a gap between the houses. Presumably they would have affixed an additional skin to our previous external wall, for their property. The difference in dpc levels could be coming into play here. That said, the 'damp' does still appear very high for rising damp.

In the image below, mine is the property immediately to the right of the telegraph-pole.

 

[mrrusty]

I wonder if neighbours roof flashing against the parapet wall is a factor?

 

[blup]

A rendered external wall that was plastered and enclosed by our extension took a year to fully dry out, the kitchen units were fitted and the room used, but not painted until fully dry. The "new" walls dried out quickly.

Blup

 

[drpepe]

This is interesting.

The adjacent building was originally I believe, a gap between the houses. Presumably they would have affixed an additional skin to our previous external wall, for their property. The difference in dpc levels could be coming into play here. That said, the 'damp' does still appear very high for rising damp.

In the image below, mine is the property immediately to the right of the telegraph-pole.
View attachment 244049

View media item 96389
You can see the difference in heights of the front door here, and the damp coming through at about 1.4m, at the height where the previous owners 'sand and cement' treatment ended View media item 96337

 

[JP_]

That looks very wet to be rising damp. Do you have any pipes running under the floorboards? My mains water runs under my floorboards along the external wall, if that started leaking it would probably make everything very wet before any damp smell started. Could something have been damaged during renovation?

 

[RonnieE]

I'd recommend you consider getting a salts analysis test carried out. This is normally a dual test which will help to highlight if the moisture contains chlorides (tap water - direct or indirect), nitrates (rising damp from ground water sources) or neither (often rainwater ingress).

Next steps depend on the outcome of that test.