Why is does my converted attic room have condensation?

Question

The RH in the room is 65% at 65 degrees. The rest of the house is 35% RH at 65 degrees. Why is there so much humidity in the converted attic room. We have plenty of venting. We have forced hot air. Could it be possible the heating vent is introducing all of the extra humidity? We tried a dehumidifier and it solves the problem by removing the extra humidity. I would like to know the source and get rid of it (if I can) instead of running the dehumidifier 24/7 during the winter.

Answer 1

Condensation occurs when cold surface meets warm air.. Picture a cold glass of ice water on a hot day. Things need some fresh air circulation. Your attic room was possibly an afterthought and retrofitted improperly. There should have been a space left between the roof and the ceiling for air which would include a vapour barrier on the warm side and insulation next to the sheeting.

The solution is to remove the improperly installed interior ceiling and re-install a new one over a well vented and insulated roof/ceiling.

Answer 2

Replacing the shingles has nothing to do with finishing an attic. If you need more ceiling height and need to take the whole roof off then yes will be very expensive. Unless the your house was build with attic trusses or the builder added floor joists instead of ceiling joists for future expansion(seriously doubt it) your ceiling joists probably aren't strong enough to use as a floor so it will turn into a very large project.

Answer 3

Running humidifier is not the answer.



You must find the source of humidity.

could be

1) improperly exhausted bat room vent or worse gas furnace, water heater vent.

2) leaks : could be water pipe leak, or leak from the roof. or even the venting might introduce water from outside.



check out every possible water vapor entry into attic

Answer 4

Easiest fix is to install a bath fan with a humidistat hooked up to it, or run your fan in the bath while showering. Water vapor is just that, vapor, and will travel with the warm air upwards until it hits the cooler surfaces.