SOLVED. What's the likely cause (and fix) for this window mould please?

coffeehound

fenwick458 said:
is there anyone other than me here who thinks that bit of black mould in silicone joints isn't a problem? I have it on the corner of some of my windows, it seems to be an absolute B****** to remove it, without actually removing the silicone/caulk. 

what's the alternative, clean it daily with bleach? I think I'd rather just leave it and forget about it

Yes it's always going to happen.  I follow a two-step approach:

Step 1:  Spray it with mould and mildew cleaner.
Step 2: Walk away.

ninjaef

Hi guys
Just got back. I forgot to take pictures. 
I removed the trim around the bottom (blue in the pic). Full of mould all underneath and there is air coming blowing through gaps where the expanding foam either was not applied properly or has fallen away. (surprise to those who stated rather assertively that there was no need to remove the trim and/or that the issue was not related to air or water ingress from outside ). The gap where air can be felt is about 5mm and runs all along the bottom under that trim (in blue). I filled that with expanding foam all along.

There is also condensation on the inside and this has pooled up underneath the silicone sealant (red) that I have cut away . Where the two trim pieces meet , underneath , which cannot be seen in this pic , there is what I would describe as a 1x1cm "tray" with raised bezels in which standing water has collected. I have cut out the silicone sealant (covered in mould)
 
Will go back tomorrow once the foam has cured and replace the trim and reseal it. Not sure what do fill the "trays" with but silicone doesn't seem right. Wish I remembered to take the pics. Must try harder tomorrow to show this 1x1cm "tray" thing that is under (or was) silicone covered in mould at the joint I circled in red here.

One thing I have learned through this activity, is to try to investigate as best I can before coming to the forum for help .I mean I didn't even try. Had I done then I could have avoided confusion and helped others to help me. 
One lives & learns.

Jeepers_Creepers

Well done for jumping to the conclusion you wanted to jump to from the off.

Of course I cannot be 100% certain as I'm not there, but I'll say I'm virtually certain - dammit, I'm 100% certain - that there isn't any water coming in under that sill/plastic trim from the outside. The water that is causing the mould under the trim, and the water that's  'pooling' in the 'tray', has all come from the condensation that's formed on the windows and has pooled on the sill, working its way past the sealant. Almost certainly.

Having said that, it is good that you've identified a gap under the trim, and adding foam will likely allow that to be slightly warmer - a good thing.

Want to know something funny? With that trim removed - and air flowing in through the gap - I bet your condensation problems will improve very quickly... :-)  

johnferrier

mould like that on the inside and condensation running down the bay pole's i'd say that the outside of the windows haven't been sealed properly 

couriervanman

johnferrier said:

mould like that on the inside and condensation running down the bay pole's i'd say that the outside of the windows haven't been sealed properly 

I'd just say it was lack of ventilation and irregular cleaning.......but what do i know

johnferrier

those windows look like local housing authority type and looking at the poor workmanship of the trim's not being mitred id say they wasn't fitted very well either   

Jeepers_Creepers

johnferrier said:

mould like that on the inside and condensation running down the bay pole's i'd say that the outside of the windows haven't been sealed properly 

Have a look at pic 2 in the very first post. Condensation running along the bottoms of the window panes and up their sides, on the glass.

It's not even a particularly bad case of condensation - it's what probably most of the population is faced with most mornings in Winter to some degree, including me.

The mould is worse along the bottom because that's where gravity drags the water, and also where the drying air flow is compromised by the sill.

I'm not saying that the window hasn't been installed as well as it should have - I simply don't know. And since ninja has removed the trim and found a draught gap, it makes sense to carefully fill that with foam (whilst not risking bridging the cavity) before resealing with sili.

BUT, this ain't the cure. The droplets that are forming along and up these glass units is classic condensation caused by lack of ventilation (and/or too much water in the house, or not enough heating in this room compared to others). The pane with condensation in the first post is even in an opening frame section, so is unaffected by however poor the whole window has been installed.

What ninja is doing won't be wasted, but I also hope they'll tackle what the actual issue is.

coffeehound

Jeepers_Creepers said:
The droplets that are forming along and up these glass units is classic condensation caused by lack of ventilation (and/or too much water in the house, or not enough heating in this room compared to others). The pane with condensation in the first post is even in an opening frame section, so is unaffected by however poor the whole window has been installed. 

What ninja is doing won't be wasted, but I also hope they'll tackle what the actual issue is.

I think that is a wee bit unfair to ninjaef.  They've already stated (though you seemed to miss it) that the room is well aired and heated.  As you say, this probably does happen in almost every home to a greater or lesser extent.  The bottom of window frames is likely to be the coolest spot in a room, and if it falls below the dewpoint overnight, then there's going to be condensation.  I get it in this room even though the heating has been on 24-7 for months and the RH is below 50%.  It doesn't necessarily mean inadequate heating or ventilation.

couriervanman

coffeehound said:

Jeepers_Creepers said:
The droplets that are forming along and up these glass units is classic condensation caused by lack of ventilation (and/or too much water in the house, or not enough heating in this room compared to others). The pane with condensation in the first post is even in an opening frame section, so is unaffected by however poor the whole window has been installed. 

What ninja is doing won't be wasted, but I also hope they'll tackle what the actual issue is.

I think that is a wee bit unfair to ninjaef.  They've already stated (though you seemed to miss it) that the room is well aired and heated.  As you say, this probably does happen in almost every home to a greater or lesser extent.  The bottom of window frames is likely to be the coolest spot in a room, and if it falls below the dewpoint overnight, then there's going to be condensation.  I get it in this room even though the heating has been on 24-7 for months and the RH is below 50%.  It doesn't necessarily mean inadequate heating or ventilation.

The OP claims the window frames are cleaned every week by daughter and opened every day  which is certainly not the case judging by the photos

neilmcl

couriervanman said:

coffeehound said:

Jeepers_Creepers said:
The droplets that are forming along and up these glass units is classic condensation caused by lack of ventilation (and/or too much water in the house, or not enough heating in this room compared to others). The pane with condensation in the first post is even in an opening frame section, so is unaffected by however poor the whole window has been installed. 

What ninja is doing won't be wasted, but I also hope they'll tackle what the actual issue is.

I think that is a wee bit unfair to ninjaef.  They've already stated (though you seemed to miss it) that the room is well aired and heated.  As you say, this probably does happen in almost every home to a greater or lesser extent.  The bottom of window frames is likely to be the coolest spot in a room, and if it falls below the dewpoint overnight, then there's going to be condensation.  I get it in this room even though the heating has been on 24-7 for months and the RH is below 50%.  It doesn't necessarily mean inadequate heating or ventilation.

The OP claims the window frames are cleaned every week by daughter and opened every day  which is certainly not the case judging by the photos

Not to mention using the room to dry clothes off the radiator.