DIY Doctor

Main navigation

Unbelievable condensation on sash windows

Postby Jeemy » Mon Nov 03, 2008 4:42 pm


I have old-style, 6 panels per frame, single-glazed sash windows.

I reputtied them for the winter, but I'm really struggling to paint over the putty.

Basically they get so much condensation on them it gathers in pools at the base of each panel, and just dissolves the water-based gloss I've been using.

I managed somehow to get the undercoat on but its just non-stop.

I've tried wiping them down with kitchen tissue but the condensation just comes back.

I tried a flotilla of hairdryers but as soon as I switched them off to go to sleep, the condensation came back.

I'm out of ideas - can anybody help?

The windows are set back inside the walls by about 70cm, i.e. my walls are 70cm thick.

I hope thats enough information, but I'm really struggling to work out what to do here.

Many thanks,

Rank: Labourer
Progress to next rank:
Posts: 4
Joined: Mon Nov 03, 2008 4:37 pm


Simply Build It

Postby TheDoctor4 » Mon Nov 03, 2008 4:45 pm


Have you had a look at the DIY Projects area at all: There are several projects related to condensation that may provide you with some help.

Rank: Project Manager
Posts: 16777215
Joined: Tue Jul 24, 2007 9:12 am
Location: Somerset in the UK in Shepton mallet

Postby Jeemy » Mon Nov 03, 2008 5:44 pm

I did indeed look. These are not double glazed windows, or toilet cisterns, so that left Condensation - Our Guide.

The only advice in that was to install Trickle Vents to the windows. But I'm not really sure what these do, so that's why I asked for advice.
Rank: Labourer
Progress to next rank:
Posts: 4
Joined: Mon Nov 03, 2008 4:37 pm

Postby welsh brickie » Tue Nov 04, 2008 9:00 am

you will always get condensation on these windows
when you sleep at night warm air from you breathing will cause it
trickle vents will help but wont stop all of it.
the only way is to leave the top window slightly open.
Have you considered upvc inserts,you just remove the sliding sash window and are fixed against the outer bead,its much cheaper than full replacment windows and wil save money on your heating,plus no more condensation
welsh brickie
Rank: Project Manager
Posts: 2612
Joined: Sat Apr 12, 2008 7:54 am

Postby Jeemy » Wed Nov 05, 2008 12:17 pm

OK, it seems like its 6 days out of 7, so we've managed to get some paint to dry on them.

Its not from moisture while we sleep as its permanently condensed, all day.

I'm going to fit a trickle vent to one of them, the worst, just to see what happens. I'll look into the UPVC insert for next spring - this is a replacement to the inner window rather than the whole unit? So glass & edging but not frame?

I can get double-glazed units made really cheaply so thats probably the same thing.

Thank you very much for your help.
Rank: Labourer
Progress to next rank:
Posts: 4
Joined: Mon Nov 03, 2008 4:37 pm

Postby id99999uk » Tue Nov 11, 2008 2:16 pm

ventilation and air moisture are the issues here, as the windows are single glazed they will always be the coldest part of the room , assuming this temperature is below the dew point of the room you will have condensation
Rank: Apprentice
Progress to next rank:
Posts: 6
Joined: Tue Nov 11, 2008 1:48 pm

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics