Skylight Leaking

jason97z28

Just curious getting ready to go out to a house that had called and said roof does not leak, but skylight forms condensation from the inside of the house around the skylight...What could this be caused by???

Thanks

Ed the Roofer

1st rule out that the skylight is in fact not leaking. Check for broken seal on skylight windows, hopefully it is a double pane with energy efficient gas, but probably not.

Many times, excessive internal humidity levels create substantial condensation. Showers, cooking, humidifier, and even extensive indoor plants getting watered.

To check skylight, remove the top frame and glass or plastic window or bubble attached and see if there are signs of water stains on the wooden curb. The interior excessive humidity may cause these conditions as well though.

Other than that, find a good replacement skylight also known as a roof window of the same or just slightly larger size and do a replacement.

Warning, years ago I had a similar situation and did everything possible and it still had condensation. Later is was discovered that the continuous soffit vents did not have the soffit wood cut out behind the vented soffit panels, and this home had a cathedral/vaulted ceiling, and even though we installed a continuous ridge vent, the airflow was not flowing. If that is the case here, then read the Air Vent brochure on hip style roofs and on the back page of the brochure it tells you how to achieve cross ventilation in rafter bays that have an obsticle in the way of the eave to ridge air flow path.

Hope this helps.

Ed

K2

I've seen condensation on skylight metal frames in sub zero temps. Basically we tied to keep the finish material tight to the metal so the warm moist air was not in contact with the metal. Wood against metal worked well. Drywall against the metal was ok. unseen areas can be foamed.

MJW

How old is the house?
It could be a ventilation problem. If it is older, then it is not built for the ventilation required with the new codes. Ice shield and newer shingles seal up alot of the ventilation it had, even though it was improper ventilation.

It could be a bad window.
It could be as simple as turning down their air exchanger. This creates alot of moisture in the home in the cold months.

If it's not a Vellux window, try to talk them into a new skylight.

Glasshousebltr

Crack a window in the same roof.......if that stops it..... change the filter on the air handler and get a dehumidifier.

Bob

__________________
Bob

Grumpy

Sounds to me like a build up of condensation caused by a humidifier in the hous being set too high.

Remember hot air rises and hot air holds moisture and our #1 cause for call backs on skylights is condensation build up causing the customer to think the skylight is leaking. This is especially true in kitchens and bathrooms where people cause steam by cooking and showering.

Glass had a good suggestion about cracking the window for immediate dissipation of the moist air, however a dehumidifier might be over kill since probably it is their humidifier on their HVAC system causing it. If not then the humidifier is a good idea. Also consider bathroom and kitchen fans to remove steam at point of use.

Additionally the tunnel between ceiling joists and roof rafters may not be insulated. I have seen this cause condensation because of the mixture of hot air meeting cold surfaces. This tunnel should have euqaly as high an R value as the walls in the house, since the attic should be as cool as the outside if properly ventilated.

Ed the Roofer

Good points on the recent posts. One more thing, Air movement minimizes the amount of potential condensation. If there is a ceiling mounted fan---use it to disperse the rising humidity thrioughout and if not then utilize a revolving floor fan.

I have had homeowners use this in their attic to minimize condensation before.

Ed