Diagnosing kitchen mildew

[TheFew]

I notice there is some green where the cold dives in to the wall. Tends to suggest to me that the wall is damp. Cold pipes will go green in a damp wall because moisture in the wall condenses out on the pipes. Whether the damp is coming from the ground, outside or a leaky stopcock I can't say. I would clean it all off and continue to look for leaks. Certainly a small leak can affect an area that big. Normally I would just replace anything that looks dodgy but that stopcock is a world of pain so better to be sure it is leaking before you replace it. I normally make sure there is plenty of room hacked out around the stopcock, clean with a little wire wool, dry everything off, and look for leaks with a little toilet tissue.

Sections off that wall are indeed damp.. flaking paint etc. I'm just note sure if the damp is due to the wall being old (1850s) and poorly DPC'd or it is due to the moisture from the pipe. When I removed the plaster from around the pipe is was very soft..

But I suspect the wall itself is the issue as similarly aged walls else where in the property have been painted white by the previous owned and are now turning yellow and flaking.

 

[pp111]

Reading your original post again it does sound like your damp proof course is not damp proof. Could be of course that there isn't one. I am afraid any fix will be long term. I would consider an injection course outside for now then when you re-do the kitchen you can consider what else needs to be done like perhaps removing some plaster low down and coating with tanking slurry and new plaster before fitting the units. Leave the pipe exposed for the moment.

 

[TheFew]

Reading your original post again it does sound like your damp proof course is not damp proof. Could be of course that there isn't one. I am afraid any fix will be long term. I would consider an injection course outside for now then when you re-do the kitchen you can consider what else needs to be done like perhaps removing some plaster low down and coating with tanking slurry and new plaster before fitting the units. Leave the pipe exposed for the moment.

I was thinking the same myself given the age of the place.

I discounted injection treatment however - as all I read about it is that is is a bit of a con and does not really help. So that has put me off.

I was also unsure about how tanking works... I assumed it just traps the moisture in the bricks.. which does not seem like great idea either.

Clearly I have lots to learn.

 

[BigBoy]

A property of that age won't have a doc and most likely the solid floor was installed much later in its life.

Injected doc can cause more problems and cost you much more in the long run.

 

[TheFew]

Having more of a look, some of the damp issues are clear caused by a breached DPC. As you can see in the below pictures, the outside wall opposite the sink has a slate DPC and there is a concrete base less than half a brick below the DPC. So clearly splashing is an issue. It also seems that the concrete door step breaches the DPC.

So no sure what to do. Digging the concrete out may help.. but I guess it is there for a reason, and I think it houses bits of the drain as there seems to be a rodding hole in the concrete (assuming that is what it is - not looked yet.)...

 

[Jim_76]

Reading your first post, am I right in drill holes suggesting cavity insulation fill?
You may have weep points above the DPC, but cavities filled in this way leave no air gap, if it’s a “wet” wall it could draw moisture in rather than letting it drain.

 

[ANDARIAL]

If holes in brick=damp proof injection
If holes in joints=cavity fill
At least that has always been my observation on site

 

[Jim_76]

If holes in brick=damp proof injection
If holes in joints=cavity fill
At least that has always been my observation on site

Yeah, just throwing another thought on pile. I've seen plenty of issues with cavity fill over the years.

 

[TheFew]

The house is an 1850s core with a number of 80s and 90s extensions. The extensions do seem to have cavity wall insulation (10p size drill holes at regular intervals in the mortar joints), and the lounge does seem to have two patches just above the skirting board where where the plaster has bubbles.

The kitchen wall however is from the 1850s and does not seem to have been cavity filled, so I think the damp is more an upward breach of the DPC. The cavity wall idea, also probably would not account for an internal wall between the kitchen and hallway also having some of the same issues.

So I guess the question is... is the concrete a few cms below my dpc.likely to be structural at all?

 

[Jim_76]

If there’s no insulation in your kitchen wall cavity, it could be your dew point is causing an issue?

 

[TheFew]

If there’s no insulation in your kitchen wall cavity, it could be your dew point is causing an issue?

Sorry if I am being dim,.but could you elaborate? Not sure what you mean by that. Thanks.

 

[Jim_76]

Sorry if I am being dim,.but could you elaborate? Not sure what you mean by that. Thanks.

where the heat meets cold and moisture forms, with no insulation the cavity will be colder, possibly a poor example, but think single pane glass in the winter with moisture forming on the inside of glass.

 

[TheFew]

OK thanks. Could be i guess. How would I cure something like that?

 

[200sols]

Move house

 

[Jim_76]

OK thanks. Could be i guess. How would I cure something like that?

Bare in mind it's just a suggestion, without investigating thoroughly nobody would be able diagnose it. Have you noticed if it is a seasonal issue at all? Removing a brick from the outside would allow you to get a moisture meter in the cavity.... that would confirm or eliminate it as an issue. Having said that, if you have an internal wall giving you the same issues I'd say it's unlikely that the lack of insulation is the problem.

 

[TheFew]

No. Seems to be an ongoing issue, not seasonal.

 

[SeatIbiza]

RE cavity walls, very unlikely it has them. It looks solid wall to me on the brick pattern. That airbrick looks a bit low, but not disastrous.

DPC (which will be slate most likely) should be 150mm from the ground level...

 

[TheFew]

RE cavity walls, very unlikely it has them. It looks solid wall to me on the brick pattern. That airbrick looks a bit low, but not disastrous.

DPC (which will be slate most likely) should be 150mm from the ground level...

Totally agree, but not sure if digging the concrete out is a good idea or not. Not sure what the purpose of it is...

 

[SeatIbiza]

Totally agree, but not sure if digging the concrete out is a good idea or not. Not sure what the purpose of it is...

Is only part of it concrete and the rest gravel on dirt?

The age of the house dictates it's likely lime mortar and the paint on top won't allow it to breathe outwards so it's going inwards. Hard to remove though. here is a product called stormdry that works kind of like goretex - waterproofs but allows walls to breathe.

The air brick provides ventilation to the subfloor. I had similar...including the stupid pipe buried in the wall. The joists were completely rotten and the whole floor had to replaced with new, air bricks moved (they were at ground level allowing water in). It takes a fantastically long time for things to dry out in properties as well.

This is a rubbish time for drying things out as well, but a fan works very well - doesn't even need heat.

 

[TheFew]

Yeah I think the concrete strip is about 1.5 foot wide, the it is compact aggregate over soil. It all drains well even in heavy rain.

Agree the paint does not help. On the side of the house that gets the weather it is slowly flaking off, so I help it along with a scraper every so often.