Mouldy uPVC windows/doors & condensation :(

[swiftgti]

Hi all,

We moved into our first house around a year ago and have recently noticed that there is black mould around most of the insides of the window frames at the bottom, and along the back door..
All of the windows in the house have condensation on them which is obviously causing the mould, but these are uPVC double glazed windows (and the back door) so I didn't think they were supposed to get much (if any) condensation?
The house was built 2005 and has insulation in the loft, central heating throughout (atm it's on for an hour in the morning and then back on around 4.30 > 8.30)
The house goes off cold quickly when the heating goes off which leads me to suspect something isn't right with the window fitting as the glass is quite cold to touch on the inside.
I took a few photos, first is one of the downstairs windows.. I was wondering if the bit where the red arrows are should have some silicone or something in it as it seems to be a 'void' from what I can tell.
http://img685.imageshack.us/img685/3806/img5251.jpg
The second is an example of what most of the windows and doors look like.. there is what I can only describe as 'black sludge' along the seam (on the inside facing side) we cleaned this off when we moved in thinking it was tar from the previous owners smoking or something, but it's come back, and now there appears to be mould growing from it!
http://img687.imageshack.us/img687/4766/img5252a.jpg
Now I know some people will say ventilate but when it's so cold outside how exactly without making the house freezing ?
All windows have little vent flaps at the top which were open all summer and have now been closed because they let through such a draft.
Surely this much condensation points at something wrong with the fitting rather than a ventilation problem ?
Yesterday I wiped dry an upstairs window, dried the sill and this morning both panes are condensated and there is a pool on the sill where it's ran down the window..
Just two people in the house, nobody showered or anything since I wiped it dry.

Sorry for the long post, but I'm looking for ideas on anything I can do as we can't afford to get the professionals in as we are currently saving for our wedding next year..

Any advice would be appreciated!

 

[freddiemercurystwin]

Leave the vents open and wear an extra layer, new houses are not as efficient as you like to believe. The glass on the inside is bound to be cold, its only 4mm thick with a small cavity and another layer of 4mm glass. Your problem is condensation, you cannot have a warm house and no ventilation unless you spend a fortune on heating. More so nowadays as there is so much emphasis on air tight homes. The Building Regs have a ventilation versus air tightness thing going on at the moment. That draft you can feel through the trickle vents is your ventilation, whilst its blowing in in some it will be blowing out through others and taking moist air with it or thats the theory!

 

[kubera]

Hi swiftgti.

Have you tried leaving the trickle vents open in the rooms you are not sleeping in? and see if that keeps the window dry??? Then in the morning you could always close the flaps.

I am in a similar position to yourself, but my windows are much older double glazing with a stupid rubber trim on the inside and my glass is much thinner and I have no trickle vents.

 

[JohnD]

...Now I know some people will say ventilate but when it's so cold outside how exactly without making the house freezing ?

if you insist on creating water vapour in the house by breathing, cooking and showering, then that water has got to go somewhere. You can either wipe it off the windows and walls as condensation, or you can ventilate. Your choice.

Start by using extractors in bathroom and kitchen, then work through the other suggestions. //www.diynot.com/wiki/building:condensation_in_houses

I hope you don't drape wet washing about the house or use an uvented drier.