Mouldy smell understairs - with no obvious cause

[warpkid]

Hi,
Firstly I should probably say that I am a complete novice when it comes to DIY - I know pretty much nothing.

Me and my wife have just purchased our first home and are generally very pleased. However, one niggling fault seems to be the cupboard under the stairs.
When we moved in we noticed that when the door was opened we were greeted with a very string mould smell. The cupboard was almost empty with no signs of damp. The only item in the cupboard was a pile of spare kitchen floor tiles. I assumed nothing of it and hoovered it out thinking it was an air flow issue.
Days past and the smell remained. I moved the tiles and discovered water underneath them. I guess that the large stack of tiles had been condensing water and mould had grown on the skirting board and floor. I took the stack of tiles out and cleaned the mould away.

Again, a few days past and the smell seemed no better. I then ripped out the carpet thinking this may have absorbed the smell. Underneath are standard 1970's esque plastic floor tiles that are glued to the concrete - again no sign of mould.

I bleached the walls, hoovered and have left the door open for a few weeks. I have also had a dehumidifier in their for a while, which has collected a normal amount of water.

After all that, the room still stinks. If I close the door few the day I will be greeted with a build up of mould smell (an earthy smell).
The brickwork seems damp free, as does the plastic tiling. I even took up a couple up to check the concrete beneath and all seems OK.

The house was build in the 70's and renovated in 2006. The floors downstairs are solid concrete and there are no visible airbricks or vents on the outside.

I am total novice so have no real idea what to do. I just want to not have a cupboard that seems to serve no purpose but generate foul mould smell.

Thanks

 

[SparrowHawk99]

I'm a competent DIYer - Is it a basement area or is the house entirely above ground level?

The issue is poor ventilation. If you are seeing mold in areas like where you described, chances are there is a high level of saturation in the air... caused by cooking/cleaning/showering etc.. these activities give off high level of moisture vapor, so do occupants perspiring and breathing (giving out moisture). If air is pretty stagnant in the house it is great conditions for mold, especially in corners like under the stairs where you describe.

Do you have trickle vents in your windows? Do you have double glazing? Do you get condensation on the windows? Do you have an extractor hood in the kitchen?

I would first consider trickle vents in all windows, extractor fan in kitchen if you don't have already, extractor fan in bathroom/all wet rooms.. this will take a lot of moisture out of the house at source

The last thing to do would be to check the concrete floor to see if there is adequate damp proof protection, e.g. a membrane.

If only plastic floor tiles are now the only thing left above the concrete, take them out and place to one side to get air in the corner. Could take many weeks/months before it properly dries out by doing above measures, and then you can flop the carpet back over the top

 

[warpkid]

Thanks for the advice!

The room is above ground level. I also have been very hot on keeping it ventilated. The door has been left ajar and I have a device in there absorbing moisture (its collected about a cup full in the last 4 weeks).

I have trickle vents in the windows which are open and I've been leaving windows and doors open when I can.

I suppose the next step, as you say, its to remove the old 1970s floor tiles, which have been glued down pretty tight (so stylish)

Im half tempted to have someone knock the cupboard through and just have a space under the stairs as opposed to a cupboard I cant really use.

Thanks again for your advice - very much appreciated.

 

[big-all]

you need to move the air
if you open the door it doesn't ventilate the space if there is no airflow
of course you need to cure the problem but something like a fan at low level to move the air would help a lot more not necessarily a large fan just something to move the air

 

[joe-90]

I'd check your drains if I were you. Condensation won't cause that level of problem.

 

[warpkid]

Hi,

Sadly its not really practical for me to run a fan in there for anything length of time.
I could perhaps do this for a couple of days but as a long term solution I don't see it.

The exterior wall is free of any damp and the drains seem fine but yes, my gut instinct tells me that its not condensation (although I could be wrong).

The smell is just too strong and despite bleaching the room out the smell builds up again very quickly.
But, I cant see what else it could be. Something within the stairs themselves?

 

[joe-90]

It always ends up involving the sewers. Do they run anywhere nearby?

 

[SparrowHawk99]

If you don't really use the cupboard, rip it out and dispose.

Can you post any pictures?

See, what happens is the moisture rises up through the concrete and some of it gets trapped under the plastic tiles with nowhere to go, so its traveling along and underneath those tiles to places you don't want it. Even if its not the main problem, which it could be, it cant be helping matters.

You say you've lifted a few and can't see mold... I would hazard a guess and say the glued down plastic tiles are acting as a sort of unwanted vapor barrier allowing a vehicle for the moisture. I think once the tiles are displaced you'll see an overnight improvement

 

[big-all]

Hi,

Sadly its not really practical for me to run a fan in there for anything length of time.
I could perhaps do this for a couple of days but as a long term solution I don't see it.

The exterior wall is free of any damp and the drains seem fine but yes, my gut instinct tells me that its not condensation (although I could be wrong).

The smell is just too strong and despite bleaching the room out the smell builds up again very quickly.
But, I cant see what else it could be. Something within the stairs themselves?

if your at the house you could "waft" with the door 2 or 3 times every time you pass this will be enough to air the space but not remove the damp just change the air

 

[warpkid]

If you don't really use the cupboard, rip it out and dispose.

Can you post any pictures?

See, what happens is the moisture rises up through the concrete and some of it gets trapped under the plastic tiles with nowhere to go, so its traveling along and underneath those tiles to places you don't want it. Even if its not the main problem, which it could be, it cant be helping matters.

You say you've lifted a few and can't see mold... I would hazard a guess and say the glued down plastic tiles are acting as a sort of unwanted vapor barrier allowing a vehicle for the moisture. I think once the tiles are displaced you'll see an overnight improvement

Ill have a look at getting some pictures.
I think removing the tiles may be the next step - they are pretty awful.
Should a concrete flaw need to breath out of interest?

Thanks for your, and everyone else's advice btw!

 

[JohnD]

There is probably a leak under the floor. Have you got a water meter? Does the bubble ever stop?

 

[SparrowHawk99]

Remove the tiles first. I doubt very much those plastic tiles were ever designed to sit shoulder to shoulder with the concrete