Window leakages and black mold

[Consigliere]

Currently experiencing window leaks when it rains heavily and also a lot of black mold - unsure if they are connected (probably), and need to get this sorted as it can't be healthy.

Any ideas on what I need to do or which tradesman to get round to fix it?

P.s. only windows if affects are the two bay windows, all the flat windows are perfectly fine.

[Hoofy]

Might not be leakage but a bad condensation build-up that's had water pooling and then running down the walls. Do you use a dehumidifier (or open the windows regularly)? If not then my guess is probably correct. If you already take measures to reduce humidity then my simple answer is not correct and you'll need someone cleverer... but it's always best to rule out the simplest... and cheapest solution (£0 to open the windows or £200 for a dehumidifier)!

[DonkeyApple]

Consigliere said:

Currently experiencing window leaks when it rains heavily and also a lot of black mold - unsure if they are connected (probably), and need to get this sorted as it can't be healthy.

Any ideas on what I need to do or which tradesman to get round to fix it?

P.s. only windows if affects are the two bay windows, all the flat windows are perfectly fine.

Any idea where the leak may be stemming from? I favour working out the source of a problem prior to hiring anyone. Re the mould, just clean the windows!

[andyxxx]

I am not saying there are no leaks (but as has been suggested) it looks like a bad condensation problem. Spray this on:
https://www.wickes.co.uk/HG-Self-Acting-Mould-Spra...

It will kill the mould, then run a dehumidifier to stop the problem re-occurring.
(obviously then check for leaks when it rains)

[OutInTheShed]

Those windows are pretty old?
Glazing installed from outside?

Blocked drainage ports are worth looking for.
Other than that, you need to just look I'm afraid.

There are small firms who are good at finding and fixing DG problems.


I would wipe that mold off with something from a trigger spray.
Just wipe it over every day in the damp season.

[Consigliere]

They were here when we moved in so at least 10 years old but likely older.

There is obviously the condensation problem, but I think there is a leak also, it manifests when the windows are washed or when there is heavy rain.

I think externally the underside and sides of the cill may not be fully sealed or at least perished over time.

Maybe time for new windows.

[Panamax]

Tell us about your trickle vents.

My bet is someone's double-glazed an older property and failed to introduce appropriate ventilation

[Promised Land]

From the pictures it looks like a bay window, what roof is on? A GRP one just put on top and leaded flashing upstand or a timber cut roof?

First port of call is get up a ladder to check gutters, rainwater pipes, if it’s a GRP roof chances are no guttering is around the bay so water runs off the roof and tracks down the windows, bottom section of window/ brickwork in the reveals could let water in but a modern looking house so you should have cavity trays, weep holes to stop any water getting through the outside facade past the cavity.

Hence not allowing it into the internal wall/ plaster area, it hits a cavity tray or weep hole over a lintel and goes back outside.

But start at the top and work down so gutters, RWP first.

[OutInTheShed]

Consigliere said:

They were here when we moved in so at least 10 years old but likely older.

There is obviously the condensation problem, but I think there is a leak also, it manifests when the windows are washed or when there is heavy rain.

I think externally the underside and sides of the cill may not be fully sealed or at least perished over time.

...l]

There's always some leakage past the galss seals, into the frame, more so as these things age.
There's supposed to be a way out for that, the frame should not be sealed to the cill.
The drain ports get filled with dead insects and general crud.

Some windows have a drain port in the front face of the bottom rail. With a little snap-in cover
A man who knows his sections may be able to drill a new drain port.

[Harmonica]

It's already been said, but the drain ports externally could be blocked. The windows look to be externally beaded so potentially 70s/80s.

I would open the windows give all the ports and casements a thorough clean and then remove all the old silicone internally and clean the mold. Leave it at that and see if you identify any weeping moisture.

If you have damp patches, then I would suggest something externally has failed. It could be something as simple as deteriored sealant or flashing failure.

It will be worth checking the gutters aren't blocked as well.

[Consigliere]

Small update - did spend a few hours on the weekend cleaning all the mold, all came off very easily with cleaner and a cloth, also cleaned out all the drain holes.

Ill keep an eye out and see if it makes any difference

[Hoofy]

Did you get a dehumidifier? If not, it will come back. Unless you leave the windows open all the time. Which is fine except it's getting cold outside!