Mould behind kitchen units

[Husker]

Hi there,

6 months ago we had a new kitchen fitted in an old house and I have recently noticed a mould build up behind one of the bottom units which has no backing as it houses the gas meter. After a closer look I can see that the mould spreads along the wall behind the other units, which do have a backing.

We had the whole kitchen damp-proofed and a DPC put in, so I think the mould is caused by the damp caused by the condensation from the water pipes which the builder did not insulate with that grey foam lagging.

My issue is that access to the wall to clean, paint with anti mould paint and install pipe insulation is near impossible without removing the units or at least removing the cupboard backing (which will break).

What would you recommend? I have a fear that we will need to get someone into help us take out the units. Should our original builder have insulated the pipes?

Any advice would be much appreciated.

 

[JohnD]

in case of condensation, add ventilation.

If that doesn't work, add more ventilation.

Pipes do not "cause" condensation. they just show it. it is caused by excess moisture in the air. However if pipes are leaking, they cause damp.

Do you hang wet washing about the house, or use an unvented tumble drier, or do steamy cooking with no extractor running?

"anti condensation paint" is just about useless. Anti-mould paint is not the answer, you need to remove the damp. Once that is done, the mould will die. If the wall is an external one, you can make a hole in it and fit a vent or airbrick to ventilate behind the cupboards. You can hire a big drill to do this and it is quite easy. But work on ventilating the room first.

You mention an injected DPC. Tell us more about the damp problem that this was supposed to cure. Also tell us how damp the other side of the wall is, and if it has a leaky pipe, dripping gutter or splashing drain near it.

//www.diynot.com/wiki/building:condensation_in_houses

 

[Husker]

Hi there,

Thanks for the reply!

The DPC was put in to stop the damp that was coming in from outside (its the outside wall on an end terrace house) and it went round the room at a set height from the floor. The outside wall has no guttering or drains etc its just old. They also chipped off the plaster all around to a height of about 3-4 feet and replaced it and coated it with some such stuff.

The mould we are seeing is above the treated area and all around the pipes. The wall is not wet to the touch and the mould is black and dusty, but the pipes are wet.

My main issue is access to the area to clean and treat and also if we wanted to knock out a few bricks and replace them with air bricks. Removing a recently installed kitchen unit that runs along the entire wall is not something I am happy to do myself, so I guess we will have to bite the bullet and pay someone (again!).

Cheers

 

[JohnD]

you might consider drilling a hole from outside. then most of the dust will be outside, and if you hire a core drill it removes a plug of brick that you remove towards you.

using a core drill is very very very very much quicker and easier than hacking out bricks.

105mm (4-inch) is the most common size, and you can fit plastic grilles as used on extractors. if it is a cavity wall you line the hole with plastic pipe. You might also consider a 50mm (2-inch) hole at each end of the run of cabinets, you can get plastic covers to fit but I have not used them myself.

if you buy the plastic foam pipe lagging you can often push it along a pipe from one end, though it will snag on pipe clips.

Usually you can remove a single unit by:
undoing the screws that hold it to the ones beside it
looking for any screws to the wall or worktop
slackening off the legs so it sinks down from the worktop
then just pull it out
replacing is reverse sequence and not difficult

Where do you think the moisture is coming from?

 

[Emfromoxford]

Hi, I have exactly the same problem (and also live in oxford, maybe its a local disease!) Had any solutions yet? My issue is that we live in a 200 year old stone cottage with very thick walls, so just drilling holes is not really a simple solution

 

[JohnD]

//www.diynot.com/wiki/building:condensation_in_houses

 

[tigsmom]

I know this is an old post but I have been looking on here for an answer as I have the same problem. New kitchen, replastered, extractor fan used all the time, condenser dryer, air bricks behind units, open plan kitchen (no door) and still mildew on the walls above and behind the units on external walls. I have drawn the conclusion that this will always happen in an old house (build 1910 so no cavity wall). So I spray the walls with Mildew remover, let it drip behind the units and keep repeating. Next time I'm considering having the whole wall tiled. It won't stop the mould but it will be easier to clean. This happens in every room in my house where furniture is against an outside wall. I try to leave room for air to circulate around where possible but you can't do this with kitchen units or in small bedrooms where you can't put the bed anywhere else. My sons duvet cover regularly picks up damp marks because his bed is against the wall but there is nowhere else for it to go. As soon as Spring arrives I fling open the doors and windows, bleach the mildew and it doesn't come back until Winter. I do try to open windows in Winter too but it's not always possible and doesn't seem to make a big difference.

 

[JohnD]

do you drape wet washing around the house?

Is the kitchen floor concrete?

Have you got a water meter?

 

[AronSearle]

Condensation requires cold surfaces, it can be prevented by better insulation or more ventilation, or a mixture of both.

There have been case studies where windows are left near permanently ajar, but condensation and mould still forms on surfaces due to very poor or nonexistent insulation on dense walls (more modern houses will use lightweight block which itself provides some insulation, but still not enough to avoid it).

With a 1910 brick non cavity construction consider the following....

1. Increase the heating load, increase the ventilation, (increasing ventilation itself won't always fix it, unless it is done very excessively). Such houses worked with roaring fires and LOTS of air exchanges due to the chimney effect they provided, you need to replicate 1910 living standards. Give two fingers to global warming and be prepared to pay for a higher energy bill.

2. Apply insulated plasterboard with an in-built VCL to the walls, this will remove the cold surfaces and vastly reduce the likelihood of condensation.

1 is cheap in the short term, 2 is cheaper in the long term (cheaper in the long term, doesn’t mean cheap now).

/destroy all Victorian houses.

 

[JohnD]

There have been case studies

got a link?

 

[tigsmom]

If I could knock it down then rebuild exactly the same but to modern standards I would! I moved here from a new build and it is a shock to the system but has more space and a bigger garden than I'd get with a new house. We had the insulated boards put in when we had the bathroom done along with an extractor that comes on automatically. It's permanently on in winter and costs a fortune to run but the mould has gone!

The kitchen has a concrete floor but the rest of downstairs is floorboards over insulated polystyrene. It made some difference. It is generally a cold house, we can't really afford the heat it needs to warm up. In an ideal world I would replace our electric fire with a wood burner. I think they're ugly but they are definitely warm.

Oh, we try not to dry clothes on the radiator and tumble dry most things in winter. I also leave the oven open after I've been cooking.

Yes we do have a water meter in the garden, why?

 

[JohnD]

we had the bathroom done along with an extractor that comes on automatically. It's permanently on in winter and costs a fortune to run

An extractor fan will typically run for between 50 and 100 hours on 6p worth of electricity.

Does the bubble in your water meter ever stop spinning?

"Trying" not to dry clothes on the radiator " is not enough.

 

[tigsmom]

Our water meter is in the garden so I doubt we could get close enough to see a bubble. what does that mean?

We rarely dry items on the radiator, just occasionally some things say don't tumble dry so we don't know what else to do. They tend to be thin sportswear that dry quickly anyway. Everything else goes in the condenser dryer.

The fan in the bathroom comes on when it's raining outside yet no-one has used the shower! Doesn't seem to make sense but it's working. The ceiling used to be mouldy but since the fan and insulation went in it hasn't returned.

All the windows in the house (double glazed) have condensation on most mornings in winter. Do you think a window vac would help?

 

[AronSearle]

There have been case studies

got a link?

Heard of google?

Plenty of stuff out there if you can be bothered to read up on it, lots of books, lots of studies and papers including a number of social housing studies as they go round upgrading them. If you want a good starting point the last green building magazine (vol 24, no.3) had an article on the subject that is good for beginners, and addresses issues directly relevent to houses as described in this thread.

Nothing wrong with your obsession about ventilation, it does fix it, just the same stuff people have been parroting for 50 odd years based on 100 year old technology, times a change!

But old people get stuck in their ways, same as how old doctors can actually be the worst as they are terrible at keeping up to date with modern treatments and cures

It is generally a cold house, we can't really afford the heat it needs to warm up.

You either increase the ventillation (and add more jumpers as your house is even more cold), or increase the heat, which increases surface temperatures and reduces the need for ventillation. This is why better insulation is a proper solution (if you can afford it). Welcome to the joys of old housing.

Fireplaces are great in that they provide lots of heat and ventillation. As long as you don't mind all that nasty cancer causing pollution, and the fact that most of the house will be cold except the room you have a fire in.

Worked fine for the victorians.

 

[JohnD]

Yes, I have heard of Google. However, if YOU make an assertion, it is quite reasonable for you to support it.