High Humidity Attic

At 140 f 80 humidity corresponds to 120 torr or 16 of atmospheric pressure.

High humidity attic.

So compared to that hot humid attic the vapor pressure at the other side of the foam is a factor of six higher. Jason advani has insulated his attic with spray polyurethane foam and while his heating bills have dropped high humidity remains a problem. 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.

Ventilation is another key factor. By scott gibson march 18 2019. That s way too high. But the humidity near the attic floor never gets out of control.

Attic moisture usually appears because of condensation. If there is excessive moisture accumulation in your attic it will condense on cold areas mainly on the underside of your roof deck. In contrast the humidity near the ridge in the attic gets very high. The dew point and rh get up close to 90 f and 90.

As planned the r 40 worth of insulation has drastically reduced his heating bill but now he faces another unexpected problem. During the winter months the recommended relative humidity inside a house is anywhere between 30 50 percent. 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.