Skylight condensation: Help!

PianomanWest · 10-31-2007, 02:56 AM

I live in Vancouver, BC, and I have 5 skylights in different parts of the house on a very high vaulted ceilings. In the winter they drip. Sometimes in the summer too. They are about 20 years old and double-paned, but the seals I think look fine as well as the flashing. I am pretty sure they don't leak, as I've had them drip on a clear blue day. The dripping is intermittent. One time I caught it dripping and found the window dry but the edges, about 1 inch around the skylight window, wet. So I believe it is condensation. How can I stop this? Is there too much humidity in our house? Perhaps a humidity control attached to the bathroom fans? A dehumidifier? I had quotes to change the skylights for new ones and it is very expensive, and I don't think they need to be replaced.

Can anyone help?

Thanks in advance.

PianomanWest

**AtlanticWBConst.** · 10-31-2007, 05:59 AM

Explanations:

From this Website: http://www.buildingtalk.com/news/rph/rph110.html;
'It has long been recognised that metal rooflights, like metal windows, are susceptible to condensation'.
'In the past, people with metal frame windows were used to the resulting moisture that inevitably dripped down from them'.
'They accepted this and lived with it because, at the time, there was no real way of preventing it'.
'A house's occupants generate water vapour through everyday activities - whether it be bathing, washing, cooking or even just breathing, and it is this - inevitable - moisture vapour that condenses as water droplets on relatively cold surfaces, such as metal windows or rooflights'.
The air we exhale is itself saturated with moisture.
In fact, in the average four-person household, the occupants themselves can generate from 8 to 24 pints of water every day.
When moisture can't escape to the atmosphere outside, it condenses on any available cold surface'.

Also, from this Website: http://www.replacementwindowskey.com...densation.html
"Condensation occurs where moist air comes into contact with a surface, which is at a lower temperature, such as a window. Condensation in houses is mainly a winter problem. Generally, it forms when warm moist air is generated in living areas and then moves to the colder parts of the home.
Preventing Window Condensation:
Condensation is encouraged by poor air circulation where stagnant air pockets form. Mold growth is the first sign that you have poor air circulation. One way to not only prevent mold growth, but also the condensation forming on your windows, is to install proper ventilation that is consistent through out the whole house.
It is common for condensation to form on single glazed windows. If you do own single glazed windows, you may want to invest in secondary glazing. But remember that you should not install the secondary glazing on all of your windows, for some ventilation is essential.
Other options include adding exhaust fans, a dehumidifier to your heating system, and having your heating and cooling system checked for blockages. If these suggestions do not solve your problem, you may need to install brand new windows. Consider new double-glazed windows or new wood or vinyl framed windows with spectrally selective glass."

Also more information: http://www.onthehouse.com/wp/20030113