Obviously the frost is caused by moisture in the attic air.
Frost in attic north side.
If left untreated it can damage critical structural elements of the home such as the trusses and rafters ruin insulation damage any stored belongings and lead to the formation of potentially toxic black mold.
The frost is on the north side since the south side receives more sunlight over the course of the day during winter in the northern hemisphere.
When the moisture gets into the attic it condenses on the roof.
The sun will sometimes warm the south side enough to thaw and evaporate moisture but leave it still coated on the north side again not a problem unless the ice starts to build up.
In most cases rolled or batt insulation will have a vapor barrier already attached.
As to the frost there are a few things you can check.
A few years ago we had a lot of frost and a company came in and charged us 250 to spray the exhaust fan and duct to stop leakage.
There was also frost on the west wall on the north side of the dormer where the sun doesn t get to it this time of year.
The insulation on the floor of your attic needs to have an approved vapor barrier installed on the warm in winter side of the insulation.
If you re further baffled by frost forming on one side and not the others you re probably looking at the north side.
You can prevent these problems from occurring by maintaining a dry attic with a low relative.
There is no snow on the roof.
How much frost should you have in an attic.
We still have one area in the rafters between the bathroom and a walk in closet that has some frost.
During winter conditions attic frost is a problem associated with attic bypasses.
To start frost shows up in the attic when moisture laden air from the house gets into the attic.
That s about it pretty simple.
You can t fully eliminate that moisture but you can try to limit it.
Condensation in the attic is a serious problem that must be addressed by homeowners.
On the vapor barrier the insulation should be labeled at least an r 30.
During the day as the sun is out in certain circumstances it will produce enough heat to warm the south side and allow it to thaw and evaporate moisture but the north side will still have frost as it does not get warm enough to cause evaporation.
In some cases frost will form on the northside of the attic sheathing and not the south.
When the outside temperature rises again the frost thaws water collects and can leak into your house.