Current building codes across the united states require attic ventilation.
Attic insulation problems in cold climates.
In heating climates attic ventilation usually provides a measure of protection from excessive moisture accumulation in the roof sheathing but if indoor humidity is high and humid indoor air leaks into the.
In fact the attic is almost always warmer than the outside so it warms the air allowing it to hold more moisture.
You can also run the fan longer at least 10 to 15 minutes after showering is a good baseline so the ice melts or doesn t freeze in the first place.
So if that cold dry air enters your attic usually nothing happens.
The common solutions to this ice problem are to use a higher powered fan use a larger diameter shorter duct run and wrap the pipe with better duct insulation.
Repeat until you ve covered the entire attic.
In cold climates the primary purpose of attic ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow tobiasson et al.
When done correctly attic venting can reduce the potential for condensation in winter and summer.
The table below shows what levels of insulation are cost effective for different climates and locations in the home.
If anything outside air passing through the attic tends to dry it out because that cold dry air sucks the excess moisture from the attic.
The best approach for a vented attic in a cold climate is installing a layer of drywall with a good coat of latex paint the paint creates a semi permeable vapor barrier.
In the northern parts of the country zones 5 8 energystar recommends insulating your attic to somewhere between r49 60.
Although there clearly are potential benefits from attic vents in heating climates there are also disadvantages.
Avoiding flash and batt condensation problems.
This is why attics are ventilated with outside air.
That s a ton of insulation but you need it in these cold climates.
In this case there were two problems.
R value is a measure of insulation s ability to resist heat traveling through it.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
Insulation level are specified by r value.
During winter the primary cause of attic moisture issues stem from warm moist air infiltrating into the attic space from the inhabited areas and condensing on cold surfaces.
1994 and to vent moisture that moves from the conditioned space to the attic rose 1992.
Attics aren t the only place cold weather causes problems.
The higher the r value the better the thermal performance of the insulation.
So what was the problem.
Simply roll out a roll of insulation to the desired length and cut with a utility life for each space between the joists.
Vents can be prone to snow and rain entry that can wet the insulation and cold air blowing through eave vents can degrade the thermal performance of attic insulation.
