Commercial Attic Ventilation Requirements

However in pursuit of attic ventilation some people choose to install attic power ventilators.

Commercial attic ventilation requirements.

In theory these are excellent tools for circulating air in the attic and keeping the attic temperature low. Intake vents located at the lowest part of the roof under. According to the fha federal housing administration us for every 300 square feet of attic floor area you should have at minimum one square foot ventilation. 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.

Vented attics can be effective as long as hvac ducts are not located in them and the ceiling deck is well air sealed and insulated. Hence you would need two square feet 600 300 of attic ventilation. These are significant challenges. Ibc 1203 2 requires 1 150 th of the attic area to be ventilated but there is an exception that is commonly used instead.

Exception 1 allows you to only ventilate 1 300 th of the attic area if 50 to 80 of the ventilation occurs at least 3 above eave or cornice vents. For large volume attics such as where roof slopes are greater than 8 12 designers also should consider increasing. The same goes for attic ventilation. The intended purpose was to allow warm air and moisture to escape.

Measure the length and width of the attic floor space to be ventilated. The colder the climate the higher the thermal resistance required for the rigid insulation. The higher the interior moisture load the higher the thermal resistance required for the rigid. Cool air in hot air out attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

It s essential for reducing moisture and preventing excessive heat.