Mould in corner of wall - new house

[serotoninsid]

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.

 

[nutty nut]

First of all the downstairs one appears to be a stain but its hard to say based on the picture.

The problem with the mould spots upstairs is most likely condensation due to poor ventilation. I assume that the corner in question is facing in a general north to east diection. If its a bedroom have you got trickle vents fitted in the windows ar altrnatively a wall vent in place?

 

[serotoninsid]

First of all the downstairs one appears to be a stain but its hard to say based on the picture.

I left a paw on it and its definitely damp.

The problem with the mould spots upstairs is most likely condensation due to poor ventilation.

The room is rented out - thats why I didnt see this till now (apparantly its been there for a couple of weeks). I didnt get the heating on until probably 3 weeks later than when it was needed. Would this have had anything to do with it?

I assume that the corner in question is facing in a general north to east diection.

Its the South/West corner.

If its a bedroom have you got trickle vents fitted in the windows ar altrnatively a wall vent in place?

Trickle vents are fitted (no wall vent) although I dont think he was using them. He was opening the window instead -although maybe not every day.

 

[nutty nut]

The spot on the ground floor if its damp to the touch is most likely a water leakage of some sort. Condensation is normally not an issue in a 2 storey building. Is that part of the wall/ceiling junction directly below the bathroom or a heating pipe? Its a matter of eliminating the possible causes.

If the room on the first floor is being occupied and has not had heating on for several weeks then this would lead to a substantial build up of condensation especially with the drop in temperatures over the past while. If its south westerly facing then there's a fair old drop of condensation about. Most condensation will form on the north easterly facing sides of a house.

In my experience the trickle vents are not a success at all. For them to work even in a small way you need to create a "through draught" possibly by leaving doors in opposite rooms open but this may not be an option for you.

You may struggle a wee bit with the builder as this problem would not be an issue for him unless you can prove for example that the wall/ceiling was not insulated or proper size vents were not fitted.

Having said all that you need to examine the exterior of the wall to see if there any possible causes for water penetration. Missing downpipes or poor flashing at a roof/wall juction are the usual culprits.

 

[serotoninsid]

The spot on the ground floor if its damp to the touch is most likely a water leakage of some sort. Condensation is normally not an issue in a 2 storey building. Is that part of the wall/ceiling junction directly below the bathroom or a heating pipe?

Its definitely not below a bathroom. Heating pipe - hard to say. However, it is directly below the wall vent - venting the downstairs bathroom. Either the vent pipe may not be angled right and heavy rain is forcing itself in there perhaps? Must take off the vent grill and have a look.

If the room on the first floor is being occupied and has not had heating on for several weeks then this would lead to a substantial build up of condensation especially with the drop in temperatures over the past while.

Its been heated for the last three weeks - but could probably have done with heating for the previous three.

Most condensation will form on the north easterly facing sides of a house.

The other semi-D have that to deal with.

In my experience the trickle vents are not a success at all. For them to work even in a small way you need to create a "through draught" possibly by leaving doors in opposite rooms open but this may not be an option for you.

The trickle vents were not being used at all. Having said that, they were leaving the windows open (something I didnt want for other reasons) which should have been much more effective than the trickle vents. Anyways, I spoke to them this evening and asked them to use the trickle vents every day. Doors are usually left open so there should be a 'through draft'.

You may struggle a wee bit with the builder as this problem would not be an issue for him unless you can prove for example that the wall/ceiling was not insulated or proper size vents were not fitted. Having said all that you need to examine the exterior of the wall to see if there any possible causes for water penetration. Missing downpipes or poor flashing at a roof/wall juction are the usual culprits.

I wont be able to get a hold of the builder until Monday. Not sure what way to play it if its not water ingress. At the end of the day, its no more than 8 months since I signed for it. They're the professionals - I should be getting a functional house. Will have to wait and see I suppose...

I did take a look at the exterior wall - very difficult to see anything untoward as the soffit comes out - I suppose the problem could be there or the roof (ladder wasnt high enough to check either of those). I will check the wall from the attic next time I find the time.

 

[marty004]

Hi,
We have been having similar problems with mould in both corners of north facing side of bedroom. Problem ended up being ventilation from the shower coming from our ensuite. We had trickle vents which we always left open but they didn't seem to do the job as air was coming in and not being extracted.
We finally purchased a dehumidifier.
"A dehumidifier removes moisture from the air, thus lowering the humidity. It does this by condensing water onto a cold surface."
It's amazing how much water it actually extracts from the air.
On top of this the builders also put in place an extractor fan just above the shower. I think there are regulations now that this has to be done in all new houses. It seems to be doing the job, so hopefully you get your problem sorted as there is nothing worse than mould appearing in a lovely newly painted house.
Good luck!

 

[serotoninsid]

We finally purchased a dehumidifier.

This sounds very similar to whats going on at my place alright. Which dehumidifier did you get marty and what did it cost you?

On top of this the builders also put in place an extractor fan just above the shower. I think there are regulations now that this has to be done in all new houses.

Yeah, can't pursue the builder on that one as they never put a shower in the bathroom in the first place.

 

[marty004]

Hi,
You can get them in Argos for €100 - €250 mark.
Don't know how good our one is but it seems to do the job.
Get one for around €180 should be fine.
You will be amazed at the intake of water in a day.

We only got the extractor put in yesterday, so hopefully it will make some difference. Supposedly there is a mould killer which you can add to paint, but you would want to get to the bottom of things before you use that (can't remember the name of it though)

Good luck.

 

[Consultant]

Hi

Paint additive I think is called "Mould Stop", which you mix into any Emulsion paint. You should also treat the mould patch with water and bleach first, but as already said you need to find the cause first, before doing the DIY job.

 

[marty004]

Update - Foreman on site is getting an engineer in to look at mould in the house. They are going to drill a small hole into the bedroom wall were the dampness is and insert a small camera to insure there is proper insulation. If not they are going to pump some more insulation in between the walls (and hopefully fix hole and repaint room!)

Maybe lack of insulation could be your problem if options above don't seem to work.

 

[marty004]

They found out that some of the insulation was missing in our attic.
Hence the constant cold air on the ceiling combined with the heat in the room was causing the mould to appear. They have now filled in the long narrow gaps around the edge of the attic and they HOPE that will do the job along with the extractor fan in the ensuite. They are also going to repiant the room for us. So we shall wait and see.

ps. Dehumidifier in the room was doing wonders, however received ESB bill today and it seems to have rocketed up since we started to use it.
I wouldn't have thought they would have eaten up so much electricity?