Proper Attic Ventilation Requirements

Rafter vents should be placed in your attic ceiling in between the rafters at the point where your attic ceiling meets your attic floor.

Proper attic ventilation requirements.

A hot ceiling tells you that the attic is acting like a solar oven raising your cooling bills and. 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. 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 following are the requirements taken directly from the irc.

You can also contact your local municipality to check on building code in your area. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.

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. Touch your ceiling on a warm sunny day. Of vent for every 300 sq. Look at your eaves and roof.

Your roof vents may not look. The majority of the requirements related to attic ventilation have not changed much from the previous editions. 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.

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. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Proper ventilation necessitates that fresh air is able to find its way in the attic space while allowing stale air to get out. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

That is a huge difference in allowance.