Mould in corner of wall - new house

serotonin_sam

Have just discovered this mould/damp in the corner of one of the rooms. They're both solid exterior walls.
Theres also one other spot downstairs here

I've been in the house since March but this must have developed in the last couple of weeks.
Naturally, I will be approaching the builder but firstly, I would like to understand how this problem is happening? I just want to make sure they go about correcting it properly.

crosstownk

Dampness, usually caused by inadequate ventilation. Have the vents checked to ensure that they aren't blocked. It could also be that it is being caused by water ingress - this is more serious so get it checked by the builder and get him to refinish any damaged surfaces.

mad m

The first picture looks bad to me,once thats gets a hold it can be a one of those jobs that can be nasty.

As it was advised check vents plus check out side walls to see if there is any cracks in outside walls were water could be getting in.

serotonin_sam

mad m wrote:

As it was advised check vents

There are no vents - just trickle vents. Only one vent downstairs for downstairs bathroom & cooker.

mad m wrote:

out side walls to see if there is any cracks in outside walls were water could be getting in.

Will try and do this today.

Wertz

Jaysus...that's not coming from condensation unless your house doubles as a turkish bath.
Looks to me like water from something like a gutter or down pipe finding it's way into the wall from above and trickling down, then leeching through the skim....combine this dampness with nice central heating and mould is the result.

ardara1

You mention a solid wall - is it hollow block?
How was it supposed to be insulated?

There is 1. inadequate insulation at that point.
2. Inadequate vapour barrier at that point

I'm afraid you're going to have to punch thru the slab to find out what the builder has done - let me know.

Ventilation might cure it - by blowing a gale thru' the house taking out humidity - and all your heat with it! - it is not caused by you - it's bad construction

serotonin_sam

ardara1 wrote:

You mention a solid wall - is it hollow block?
How was it supposed to be insulated?

Its got the aerofoam insulation insert in the middle of it.

ardara1 wrote:

There is -
1. inadequate insulation at that point.
2. Inadequate vapour barrier at that point

If it was 1 or 2. how would they go about putting it right?

ardara1 wrote:

I'm afraid you're going to have to punch thru the slab to find out what the builder has done - let me know.

You reckon I should do this before calling them in? Is there a possibility that they would find a way of doing a cosmetic coverup job and not fix it properly if I bring them in without doing a bit of destructive testing as you suggested?

serotonin_sam

I finally got a hold of the builder. Had a chat with him last week and showed hima pic of it on my camera phone. Hes going to look at it tomorrow and said that he would bring the painter in to paint over it :eek:

I told him just to look at it and see what he thought was the problem - and not to paint.

mensreas

is the room upstairs or is the mould on a gable wall or a cold wall at least if it is its caused by bad ventilation, steam from shower cooker etc going to the coolest place try change the blinds to somethin lighter. if it happerns again paint it urself with GOOD undercoat or a product called "problem sloving primer" few coats should sort it out other wise ur in trouble!!!!!!

serotonin_sam

mensreas wrote:

is the room upstairs

Yes.

mensreas wrote:

or is the mould on a gable wall or a cold wall

Its most likely the coolest part of the house. Its on the SW gable.

mensreas wrote:

at least if it is caused by bad ventilation, steam from shower cooker etc going to the coolest place try change the blinds to somethin lighter.

It cant be the cooker. There are 4x showers a day in the bathroom (no extractor in bathroom) next door to it but why would it form here if that was the problem?

mensreas wrote:

if it happerns again paint it urself with GOOD undercoat or a product called "problem sloving primer" few coats should sort it out other wise ur in trouble!!!!!!

I thought it wouldnt be such a good idea to paint it. Surely thats just a cosmetic touchup without solving the underlying problem?

serotonin_sam

Builder has cleaned off the mould but I havnt seen him since that was done so dont know yet what he thinks is the cause.

I was just thinking seeing as this is happening at a wall junction (ie junction of wall and ceiling), is it a case of 'thermal bridging' thats causing this?

serotonin_sam

serotonin_sam wrote:

There are 4x showers a day in the bathroom (no extractor in bathroom) next door to it but why would it form here if that was the problem?
the underlying problem?

The warm moisture-laden air from the bathroom is the most likely culprit as it will condense on a nearby cool surface, causing damp etc..

An extractor in the bathroom with over-run and keeping the bathroom door closed as much as possible should solve the problem.

serotonin_sam

Never rains but it pours..

I now have this on my living room wall. I'm fairly sure its a result of mopping the bathroom floor (directly above) earlier in the day but I'm surprised that it a small amount of water can come through so easily like this.
I did some of the tiling myself and forgot to silicone the joints instead of grouting them so I suppose the water got down in the gap here

mad m

Theres mopping a floor and mopping a floor,but jaysus that looks like a ton of water came down wall.....Put some tissue around those radiator pipes and make sure theres not a little drip happening.

mensreas

serotonin_sam wrote:

Yes.

Its most likely the coolest part of the house. Its on the SW gable.


It cant be the cooker. There are 4x showers a day in the bathroom (no extractor in bathroom) next door to it but why would it form here if that was the problem?

I thought it wouldnt be such a good idea to paint it. Surely thats just a cosmetic touchup without solving the underlying problem?

not sure of the sicence behind it sorry but it is a cause i work in a hardware business and hear of this on regular occasions thats wot i tell the customers and it works as for painting it, the primer is oil based so it will stick to the wall and cover the damage but the scorce has to be fixed before hand !!!!as for ur tiling keep the dayjob lol bit of premixed white grout will shore that up nicley :cool:

mensreas

oh and by changein the blinds in the room to somethin lighter you are allowin the air to escape sis had similar prob and this sloved it!! like i said its a common enough prob would be better if u could get a vent
in the easist 4 u would be a inline one where the air goes up into the attic but make sure u put the end of it over the header tank so the water goes into there and not the ceiling over the bathroom as so many ppl insist on doing!!!!! lol hope this is help to u

serotonin_sam

I havnt had a chance to talk to the builder since he cleaned off the mould but was up in the attic yesterday and noticed the underside of the felt was sopping wet. Its not a case of a roof tile being out of place as its all over the back roof section.

Have never noticed this before and was up there a good few times earlier in the year. My en-suite is venting into the attic space - (but not actively as I dont use it as it isnt tiled yet).

Is this normal? If not, could it be related to the mould problem (which is now growing back)?