Proper Attic Ventilation Requirements

Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Proper attic ventilation requirements.

Of vent for every 300 sq. That is a huge difference in allowance. Look at your eaves and roof. A hot ceiling tells you that the attic is acting like a solar oven raising your cooling bills and.

Once they are in place you can then place the batts or blankets or blow insulation right out to the very edge of the attic floor. The majority of the requirements related to attic ventilation have not changed much from the previous editions. The following are the requirements taken directly from the irc. Touch your ceiling on a warm sunny day.

In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Measure the length and width of the attic floor space to be ventilated. If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. The ventilation ratios go according to attic floor size not roof size.

There should also be a 50 50 balance of attic venting and roof venting. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Regarding attic ventilation nrca recommends designers provide at least 1 square foot of nfva for every 150 square feet of attic space 1 150 ventilation ratio measured at the attic floor level ceiling. You can go as low as 1 300 of the attic floor area for attics which have a continuous vapor barrier below to a high of 1 5 in inches x the floor area in feet.

Proper ventilation necessitates that fresh air is able to find its way in the attic space while allowing stale air to get out. This is accomplished through the placement of ventilation near the bottom of the attic space at the soffits or eaves intake and at the top peak s or ridge s of your attic space exhaust. Your roof vents may not look. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

If you don t see any attic vents on the roof or in the eaves you need to add some.