Diagnosing kitchen mildew

TheFew

TheFew

TheFew

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Hello.

I was hoping for some advice on another of my property’s long standing issues – mildew in the kitchen!

My house is a mixture of 1850’s construction (brick walls with I think slate DPC) and 1980’s/1990’s construction (DPC type unknown). The whole shebang is coated in white exterior paint, which is “cauliflowering” and flaking in places, but mostly good. The newer portions of the property may have cavity wall insulation – judging by what appear to be regular drill holes on the exterior.

So what is the problem?

Essentially all of the low level cupboards in the kitchen whether they be attached to an internal or external wall from either periods of construction seem to be suffering from mildew (green-ish smelly mould), not black mould. The high-level cupboards do not seem affected.

Now I know the house has a few issues. The 1850’s wall that the sink is attached too has high damp level readings and is clearly moist with flaking paint (not sure how to resolve this – beyond improving ventilation) and the stop **** under the sink seems to be half buried in the plaster and looks damp. Also a wall between the hallway and the kitchen (1850s wall) seems to show higher damp level readings on the kitchen side to the hallway side (the hallway side has been treated with something like stabilising solutions as the bare brickwork does look like it was previously crumbly but is now firm).

When I moved in I fixed a leak in the roof and some black mould in one area, but generally looking under and behind the cabinets there is no black mould, just the smell of mildew and presence of green mould.

So the question is how to I diagnose the source of the mildew and how do I get rid of the smell form the cupboards?

The kitchen does not have an extractor fan, but I do run a dehumidifier to remove excess moisture.

Thanks for any thoughts that you may have.

Damp near sink..
MISvlZW.jpg


Under sink..

AZwHLSO.jpg
 
Is the mortar between your bricks on the original old walls lime based? That's meant to be breathable, if you put masonry paint over it, that will stop it breathing and so any moisture that gets into it from the inside of the property has nowhere to go. Not a lot you can really do about it now, same thing happened in the 40s when every Tom Dick and Harry slapped (non breathable) cement render over their old lime mortar walls.

Step 1. You say the stopcock looks damp, check it for leaks and fix it if there are any.
Step 2. VENTILATION. Old houses had crap seals around their external doors and windows and a fireplace going in the middle of the house most of the time. This meant that there would be constant fresh air drawn in through the drafty doors + windows and up through the chimney. Modern doors + double glazing and people not using fireplaces anymore means that the air gets stale because no fresh air gets in. Old houses weren't meant to be so air tight as we make them now, we apply modern techniques to old properties, you need to account for this. You absolutely need to put fresh air vent in the kitchen and an extractor fan. When you cook anything it will create a crap load of moisture in the air, do you get condensation on your windows too?


And finally, those electric damp meters are absolutely useless for measuring damp in anything other than wood, and even then you need to control for the different wood species. Read more here: https://www.heritage-house.org/damp-and-condensation/the-ping-prong-meter-guilty-of-fraud.html
 
Thanks for the comments. I will indeed check the stop **** and look to install an extractor. The kitchen does have one, but it has no vent to the outside, just charcoal filters for smells. So it is next to useless.

The utility room does have a vent to the outside, but it is small and a long way from the main kitchen.

How would I tell lime mortar from more modern types? Is there an easy way to tell?

I appreciate damp meters have limitations. I tend to use if for a relative measure. E.g. the top of the wall is x then bottom is x+15 therefore the bottom is likely damp. Or for seeing how the reads change over time. Noting that salts can also give high readings. But in essence the meter only confirms my own suspicions.
 
There is no easy way, it being old means it's likely that it is that's all. You can take some off and get it tested to find out what it is but that's a big faff. Really I think if you improve your airflow, and remedy any leaks that will solve the large majority of your problems. RE: damp meters even as a 'relative measure' they are completely pointless, the difference you can see from one part of the room to the other can be because of different paint types, different types of plaster/wood/metal etc etc. They are literally as much use as a chocolate teapot used in anything other than wood, and even then you would need tables to control for the different species of woods.
 
I've an old house with lime mortar. You can test if it is by scraping a bit off into a glass of white vinegar. If it fizzes it's likely lime. I need to get some plastering done, not looking forward to finding someone who can work with lime :/

 
Looks like a small leak on the stopcock to me
Going to be a pain to replace looking at that picture :(
Dought you could turn it off in an emergency.`looks` like you would need to remove cupboard to replace it too
 
Thanks. I will give the motar testing a go.

Re the stop ****, it is not the main water isolating point, that is at the other end of the house. So happy I can turn the water off when needed. Buy yes looks like I need to see what is going on there. As you say, it is going to be tricky...
 
Well I finally removed the back of the cupboard. I have also removed the soft and damp plaster around the pipework. Next stage to clean the corrosion off of the pipes. Not sure after that.. if no leaks are obvious.

On the outside wall is the drain. This is a concrete bordered affair butted up to the brickwork. So i may put some slate or lead between the drain and the brickwork to act as a splash back..

Some pictures of under the cupboard..

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Found another leak in the kitchen under the units.. a heating connecting with a slow weep. Makes me wonder about the skills of the plumber who installed it all.
 
What is the floor of the kitchen like? We used to liv in a 1902 house and the hall and kitchen were basically tiles, on about an inch of concrete straight onto soil. Bottom of the walls etc looked very similar and it was always damp and cold in there as there was no insulation / damp proofing under there at all.
 
gav_172 said:
What is the floor of the kitchen like? We used to liv in a 1902 house and the hall and kitchen were basically tiles, on about an inch of concrete straight onto soil. Bottom of the walls etc looked very similar and it was always damp and cold in there as there was no insulation / damp proofing under there at all.
Click to expand...

No idea at the moment. All I can see is the concrete under the tiles. In one section of the single storey extension there is a small hole in the floor tile grout along the wall edge, where ants have come in before. But that does not mean it is just soil below...
 
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.
 
Firstly.
What's on the other side of the wall? If its soil or plants make sure the level of soil is below the level of the floor or you will get rising damp.

Secondly.
Copper pipe should never be set in concrete or plaster of any type it's corrosive to the copper and will cause all sorts.of problems. The only saving grace you have is that looks to be cast copper pipe not spun copper, cast copper is much thicker than spun copper.
 
BigBoy said:
Secondly.
Copper pipe should never be set in concrete or plaster of any type it's corrosive to the copper and will cause all sorts.of problems. The only saving grace you have is that looks to be cast copper pipe not spun copper, cast copper is much thicker than spun copper.
Click to expand...

There seems to have been a fad, somewhere around the 70s or 80s, of doing just that for some reason - no idea as to the rhyme or reason :(
 
BigBoy said:
Firstly.
What's on the other side of the wall? If its soil or plants make sure the level of soil is below the level of the floor or you will get rising damp.

Secondly.
Copper pipe should never be set in concrete or plaster of any type it's corrosive to the copper and will cause all sorts.of problems. The only saving grace you have is that looks to be cast copper pipe not spun copper, cast copper is much thicker than spun copper.
Click to expand...

The other side of the wall is a drain and a gravel driveway. Oddly there is some concrete at the base of the wall and I think that is higher than 2 bricks from the DPC. But struggling to tell what the DPC is. As it is an 1850s wall I think it is slate.

Clearly most of the pipes go into the concrete floor, so will be set in concrete to some degree, but I was suprised to find it set into the plaster.

In another area of the kitchen under a different kick board I found a weeping heating pipe. So nipped that up. Just wondering what else I will find when I look at the rest!

I am slowly drill vents in the kick boards to add ventilation and wiping everything down with bleach. Saddly however the musty smell comes straight back - guess it is ingrained in the units!!
 
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