mould on sealant around the window frames

bozzy18

Hello, I notice some mould on sealant around the window frames in my daughter's bedroom. There appears to be condensation on the two windows in that bedroom but no where else in the house. I don't know why this only occurs in my daughter's bedroom - does anyone know?


Should I ask window company to come in and sort out the sealant as I expect it would all have to come off and be resealed with new sealant?


Would welcome any advice please.


Thanks.


Boz

Aylesbury_Duck

Those windows are either much colder than those in other rooms or there is more moisture in that room, or a combination of the two. Does your daughter sleep with the door closed? Are there trickle vents in that window? Have the panes blown i.e. the seal has gone so that you still have double glazing but that the vacuum or gas between the panes has gone? Is her room next to a bathroom?

With regard to the sealant, I would first try and see if you can get rid of the mould if it's just on the surface. Something like HG mould spray (you can buy it at B&Q and other DIY sheds) left overnight might get rid of the mould (get your daughter to sleep in a different room overnight that night) or just wipe the sealant with a water/bleach solution and leave overnight. If the mould is properly ingrained then yes, the sealant should be scraped back and new sealant applied, once it's all dried out and any mould removed of course.

However, get to the cause first, otherwise you're just treating the symptom and it will re-occur.

Ebe_Scrooge

bozzy18 wrote: »

I expect it would all have to come off and be resealed with new sealant?

Alternatively, a scrub with an old toothbrush dipped in a bleach solution might do the trick.


You'll always get condensation where warm, moisture-laden air hits a colder surface. As to why it only happens in one room - could be any number of reasons. Is that window single-glazed where others are double-glazed ? Is it a smaller room, so there's a higher percentage of moisture in the air, due to the lower volume of air in the room ? Is there an additional source of moisture in that room ( clothers drying on radiators, a fish tank, anything else ) ? Really, the only way to reduce condensation is to reduce the moisture content of the air. Ventilation usually does the trick, a dehumidifier in extreme cases.

bozzy18

Aylesbury_Duck wrote: »

Those windows are either much colder than those in other rooms or there is more moisture in that room, or a combination of the two. Does your daughter sleep with the door closed? Are there trickle vents in that window? Have the panes blown i.e. the seal has gone so that you still have double glazing but that the vacuum or gas between the panes has gone? Is her room next to a bathroom?

Thanks for this. My daughter's bedroom is actually the furthest away from the bathrooms compared to the other bedrooms. There are trickle vents on her windows. Her door are not closed throughout the nights; in fact we never close her door!


How do I know if the seals has gone to make the panes blown? Do you think her vents are blocked? How do I know - I can't see anything that could be blocking the vents.


Thanks again for your help.

Aylesbury_Duck

bozzy18 wrote: »

Thanks for this. My daughter's bedroom is actually the furthest away from the bathrooms compared to the other bedrooms. There are trickle vents on her windows. Her door are not closed throughout the nights; in fact we never close her door!


How do I know if the seals has gone to make the panes blown? Do you think her vents are blocked? How do I know - I can't see anything that could be blocking the vents.


Thanks again for your help.

On a windy day, you may be able to detect a slight draught, in or out, from the trickle vent. That will tell you if it is open or blocked. The double glazing being blown might manifest itself through condensation or mist inside the window unit.

Furts

Sealant between windows and the walls would normally be acrylic caulk. If you wet this, or bleach this, or scrub it then it stands a good chance of being damaged or ruined. This is because it is water based. It also softens with condensing moisture on it.


There is a partial solution. Cheap caulks do not contain fungicide, and tend to be watery. So try a better quality caulk. No Nonsense is useless here - I have stopped using it a few years back because of this. Toolstation have recently discontinued their good Siroflex(?), but Polycell seems a safe choice. I suspect the EverBuild at Toolstation is fine, but have not yet used it.


Another partial solution is to decorate over the sealant - but mould can take onto matt emulsion paint.