Condensation and mould - will new windows help?

[blahhhhhhh]

Our house is a 1950s brick terrace and the windows are, at best guess from surveyors and neighbours, about 15-20 years old, and double glazed. As the title suggests, every day we have a serious condensation problem and mould has developed all around the window frames and walls of most of the windows, particularly upstairs.

I've read all the articles about the causes of condensation, and can honestly say we don't really fit the bill for a household where you would expect habits to lead to condensation. Admittedly we don't have an extractor fan in the bathroom, but we have 2 windows and always open them during a shower and leave them open for up to several hours afterwards, which is surely more effective. I have an extractor fan in the kitchen and use it every time we cook. We do dry washing in the house, but only during the winter months and then its not an excessive amount of washing, maybe 1-2 loads per week. I never dry washing on radiators. And the landing window upstairs is permanently open on the first setting to try and ventilate a bit more... but the condensation and mould problem persists. Interestingly it only happens upstairs, downstairs is relatively unaffected.

I'm after some impartial advice from someone who isnt just trying to get me to part with several thousand pounds - will new double glazed windows actually make a difference to the condensation and ultimately the mould problem?

Our new baby is due in April and my concern is that they will be sharing our bedroom for the first few months, but our room is the worst affected. I'm running out of ideas for what to do

 

[^woody^]

New windows will do nothing for a condensation problem, and would normally make any existing problem much worse

The moist air you already have will still be there after any new windows are installed, and it will still condense on the same cold surfaces.

If the mould is around the window reveals, then consider lining them with uPVC or some thin polystyrene insulation

You don't mention heating, it needs to be on most of the time rather than in on/off cycles. Ventilation is not always the answer on its own.

If after following all the standard advice you are no further forward, then consider having a positive pressure fan fitted

 

[JohnD]

We do dry washing in the house... during the winter months

if you used a watering can to sprinkle 2 litres of water around your house once or twice a week (or ten times with a new baby) would you expect that to cause condensation, damp and mould?

New windows will not reduce condensation in the house, unless you open them.

If you decide to buy new windows, ensure they have trickle vents.

BTW water vapour is lighter than air, so it rises. Hence clouds, and upstairs condensation.

 

[NeilPalfreyman]

Double glazing certainly wont solve a humidity problem.

Drying washing inside the house is almost certainly a major factor here.

One possible solution is a dehumidifier. We bought one this winter and I'm staggered by the amount of water it extracts form the air. Hope I'm not similalry staggered by how much it will cost us to run it

 

[AronSearle]

The first thing to remember about condensation is warm air + cold surface = condensation.

Managing the humidity levels is important as it can affect the temperature gradient on surfaces needed for condensation or damp, and the amount of damp, but from what you describe you have plenty of ventilation, much more than I have with no mould or damp issues except on a single glazed poor quality door, and I dry my washing indoors (sinful!).

New windows can certainly help in that they will have warmer surfaces, and will keep more warmth in, raising the overall temperature.

However I suspect it will not eliminate mould issues in your case.

A building of your age will likely have no insulation, new windows may stop condensation on the windows, but damp may still occur in the corner of rooms, also on the window surround as it is fitted into the wall.


If you have blown in cavity insulation it is important that the window is fitted in line with this, with proper cavity closers, and ensuring the blown in insulation fully fills the voids around the windows

However cold bridging and so cold spots will likely still occur around the window frame from the lintel, and from the fact that you won't get much from filling a 50mm cavity, ceiling corners are also likely to have gaps as the wall insulation doesn't wrap up with the roof insulation.

So you will still need to ventilate to manage the humidity and reduce condensation mould issues, but it is about finding the right balance between ventilation and insulation/warmth and you might find you can reduce the level of ventilation to hit that sweet spot.