High Humidity Attic

If you have high temperatures and high humidity in your attic then you may also have a problem with mold.

High humidity attic. The dew point and rh get up close to 90 f and 90. But the humidity near the attic floor never gets out of control. By scott gibson march 18 2019. Ventilation is another key factor.

Jason advani has insulated his attic with spray polyurethane foam and while his heating bills have dropped high humidity remains a problem. If the attic is at 80 f and 80 humidity that s about a 21 torr vapor pressure of water. Freezing and excessively hot outdoor temperatures rain and high exterior humidity levels make it difficult for your attic fan and heating and cooling systems to keep up with desirable attic. In contrast the humidity near the ridge in the attic gets very high.

That s way too high. Attic moisture usually appears because of condensation. At 140 f 80 humidity corresponds to 120 torr or 16 of atmospheric pressure. The dew point and rh stay below 70 f and 70 at their peak the peak of humidity not the peak height in the attic.

Jason advani jason advani thought he was on the right track when he insulated the bottom of the roof deck in his walk up attic with closed cell spray foam. Attic temperature depends on the outside temperature and it also depends if your house is insulated. If there is excessive moisture accumulation in your attic it will condense on cold areas mainly on the underside of your roof deck.