Black Mould Problem

[Tricky Dicky]

Our bungalow has a small pantry in one corner of the kitchen and we seem to get black Mould in one corner and this year with all the rain it seems wor se. The pantry is situated in the NE corner of the house, the walls are cav ity filled and there is no evidence of damp, the pantry is vented with a si ngle wall vent.

My feeling is the Mould is due to condensation and the question is whether to seal the vent or not as I feel this is the source of damp air getting in and the air being cool the reason the condensation is happening. Unfortune tly the kitchen is not the warmest room in the house heated by a Myson kick board heater, neither is it well ventilated relying on an open window when cooking.

The improvement to the heating and ventilation of the kitchen is awaiting t he replacement of the kitchen sometime in the next two years. In the meanti me I need a solution to the Mould problem, I have bought a dehumidifier to help with RH. What is the consensus of the group regards sealing the vent? I know that good ventilation is the key to removing damp air thus controlli ng condensation but this vent seems to be the source of the cold/damp air a nd the cooling the reason condensation is occuring.

Richard

[Martin Brown]

Are you sure it is black mould and not very dark green photosynthetic algae? The latter tends to be more common since a mould needs something to live on whereas the algae just needs a damp surface.

[tabbypurr]

to get black Mould in one corner and this year with all the rain it seems w orse. The pantry is situated in the NE corner of the house, the walls are c avity filled and there is no evidence of damp, the pantry is vented with a single wall vent.

mould can only occur due to a damp problem. It is a damp problem.

sounds most likely

source of damp air getting in

This is a popular misconception. Dampness originates indoors, not outside. Indoor air is outdoor air plus water vapour from cooking, breathing, bathin g, clothes drying etc. It feels drier because it's warmer, and warm air can hold more vapour, but it still contains more vapour.

etly the kitchen is not the warmest room in the house heated by a Myson kic k board heater, neither is it well ventilated relying on an open window whe n cooking.

kitchen dampness is often caused by hob cooking on excessive power. Minimum power & a lid usually does the job once boiling.

the replacement of the kitchen sometime in the next two years. In the mean time I need a solution to the Mould problem, I have bought a dehumidifier t o help with RH.

Consider it done

good ventilation is the key to removing damp air thus controlling condensat ion but

exactly

reason condensation is occuring.

making it cold is an issue. If you run a dehumidifier you probably won't ne ed extra ventilation at all.

NT

[Chris Hogg]

+1 to all of that. The cold air coming in through the vent is going to be holding less water than the air in the pantry, because the air in the pantry is almost certainly warmer and originating from the rest of the house. Nor will the cold air from outside condense on the pantry wall, because the pantry wall will be warmer than the cold air coming in.

We get a lot of black mould on walls in Cornwall, simply because the humidity is always high down here, inside and out, due to the proximity of the sea. Mould grows on the insides of cold outside walls, particularly where there's no air circulation, i.e. behind wardrobes, free-standing cupboards, or pictures. To start with, try just a circulating fan to stir the air and keep it moving, as a cheaper alternative to a dehumidifier. If that doesn't work, then by all means use a dehumidifier.

[David Lang]

Put an electric fan in the vent hole?

[stuart noble]

Problem is, the aforesaid warm indoor air cools at night and will condense on the coldest surface. Not helped by 92% RH outside here today at 16.00 hrs

[tabbypurr]

the other problem is the silly cost of all the heat chucked out

[harry]

to get black Mould in one corner and this year with all the rain it seems w orse. The pantry is situated in the NE corner of the house, the walls are c avity filled and there is no evidence of damp, the pantry is vented with a single wall vent.

r to seal the vent or not as I feel this is the source of damp air getting in and the air being cool the reason the condensation is happening. Unfortu netly the kitchen is not the warmest room in the house heated by a Myson ki ck board heater, neither is it well ventilated relying on an open window wh en cooking.

the replacement of the kitchen sometime in the next two years. In the mean time I need a solution to the Mould problem, I have bought a dehumidifier t o help with RH. What is the consensus of the group regards sealing the vent ? I know that good ventilation is the key to removing damp air thus control ling condensation but this vent seems to be the source of the cold/damp air and the cooling the reason condensation is occuring.

Well if you are running a dehumidifier letting moist air in from outside wo n't help. The problem is when warm moist air meets cold air or cold surface condensat ion occurs. So you have to keep the moist air out as the pantry must remain cold.

Hard to do in practice, this why pantries have fallen out of favour. So better to have a fridge, do way with the pantry and seal up the vent. Pr operly with insulation and without thermal bridge. The black mould is hard to get rid of once established. You need several attacks with bleach or algicide (from a builders merchant/ Screwfix.)

[Andrew Gabriel]

Pantries on north walls were sometimes built without the cavity to make them cooler. Check if the wall in the pantry is further back than the internal walls either side.

This is quite easy to test. Stick a large square of aluminium foil to the wall where the mold is worst with wide tape around the edge to form an airtight seal. Leave it there a few days. Then inspect it carefully. If there's condensation on the room side of the foil, then the damp problem is condensation. If not, peel the tape off the wall and check the rear (wall side) of the foil. If there's condensation on the rear, then it's penetrating damp.

The fix will depend heavily if its condensation or penetrating damp. Hence you need to check that first.

Also, how well insulated in the larder from the kitchen, and how well sealed against air-flow?

Like another user said, boiling pans on the hob with open lids and/or too high a flame could be a big factor too, although I've given up trying to stop various members of my family doing this.

[Fredxxx]

You can get bleach from almost anywhere, but I'm struggling to find algicide on Screwfix.

Is black mould really an algae?

[David Lang]

[T i m]

Me too. I think all this sort of thing is a lack of understanding of science. A pan of veg boiling madly is the same temperature as a pan of veg just simmering after being brought to the boil.

Taking that further, I think some people bring rice to the boil and then turn the heat off?

I checked the tyres pressure on a van the other day and the rears were at the pressure for the maximum load. I asked why they were set so (knowing the van was mostly driven empty) and the guy said it was because the van was 'full'. Yes, it was quite full at that time but of nothing that weighed very much. I bet he would have done the same if it was 'full' of polystyrene. ;-)

Someone else, when questioned on the (potentially inadequate) load rating of the front tyres of a van stated:

"The front always weighs the same as the engine doesn't get heavier.

The weight in the back only goes over the rear wheels.

Sometimes, having weight in the back will make the front wheels lighter."

To which the only thing I could say is 'Oh' (daughter and I have worked this reply out as a shortened version of 'Oh, is that right ... as you are now talking bollox, I'll leave you to it'.) ;-)

Now, if the van had a long overhang behind the rear wheels, if the load was positioned directly over the rear axle or even behind the rear axle then some of what he said may have been true, but on that van the wheels were in each corner. ;-(

How many people struggle and strain with stuff when a simple lever would make things so much easier ...

It takes all sorts of course. ;-)

Cheers, T i m

[Tricky Dicky]

Thanks for all the advice so far even if some seems a little conflicting. A ndrew I will try your tin foil test but there does not seem to be damp evid ence certainly no marks other than the mould, no peeling or flaking paint. Regards the pantry construction, it definetly has cavity walls to the outsi de and a studded partition to make up the third wall internally. It is just a door width wide and the door is not exactly an air tight fit. I am happy to vent the door to improve air flow through the pantry. We do not store f ood in the pantry other than the cat food it houses the meters and the CU a nd is mainly filled with cleaning products and other odds and sods. Nothing stored in the pantry has shown any effects of damp. The long term plan for the kitchen will be to remove the pantry and at that point the vent will b e sealed.

In the meantime having bought the dehumidifier I am a little puzzled regard s some of the advice. Do I shut down all the ventilation and rely on the de humidifier alone or do I keep ventilation open? The manual that came with i t does not offer any advice on ventilation. Yesterday was the first day we used it and had it on most of the day, for 4 hours it was on its clothes dr ying mode and placed in the same room that SWAMBO had clothes airing. In th at time it extracted 2L of water which we emptied this morning after runnin g it for a few hours. I suspect most of it was from SWAMBOs washing. I do n ot know what the RH is but will be getting a humidity meter to monitor it. I take the point about cooking styles, unfortunetly SWAMBO is of the boil i t at max. curtesy of her convent education. This is a no go area, whatever Sister ???? said is gospel and who am I as a mere mortal with a Science and Technology degree to question such divine thoughts.

Richard

[Fredxxx]

Is that an "algecide? It looks more like a fungicide.

Hence my question to Harry:

[ARW]

Is Cornwall the only place in the UK that is next to the sea and is all of Cornwall next to the sea:-)?

[Tricky Dicky]

OK I have just taped some cooking foil to the wall, don't know if it will t ell us much as I am not getting as good a seal from the tape as I think is required. What I did notice while clearing some stuff out of the way to acc ess the mouldiest part was that there was condensation on some bottles of w ater that SWAMBO had stored, is that telling us something regards where the moisture is coming from.

As an aside my parents last house was a new build in the mid 60s and it too had a pantry albeit bigger but vented like ours and it was painted with gl oss paint likewise I remember were some of the neighbours. Was this because Mould was inevitable and glossing the walls made it easier to deal with? A t our last house the kitchen was an extension added on by the previous owne rs and the original kitchen was used to enlarge what was then the dining ro om, I noticed there that the walls of the original kitchen had been glossed ?

Richard

[harry]

Dunno but the stuff I've bought was label algecide. More info here.

[T i m]

I think there are two conflicting needs here.

1) If running a dehumidifier you don't also want ventilation as you will effectively be trying to dehumidify the world. ;-) 2) You need ventilation to ensure a good supply of fresh air for any living occupants.

I think the only way to have both is to:

1) Live in Spain or California 2) Use heat exchangers on any fresh air vents to try to minimise your heat losses.

I think it's one of those things where you *can* run it with ventilation but it would be less effective?

We currently have one dehumidifier in our bedroom and another in the kitchen / utility / bathroom area. Both will typically fill each day at this time of year.

They will generally give you a rough guide.

Get a jam thermometer and show her how the temperature doesn't go up once it's simmering. ;-)

Ah, there is no hope then. ;-(

Well, other than you can prove what you are saying is fact with science. I'm not sure she can? ;-)

Cheers, T i m

[Chris Hogg]

Well, no, I will concede that there are other seaside places in the UK. :-) But Cornwall is a long narrow peninsula, and nowhere is more than twenty miles from the sea, so you could reasonably say that all of Cornwall is next to the sea. With the wind blowing predominantly off the sea, humidity is always high.

[Fredxxx]

Yep, no algicide mentioned there either.