Best Practices Attic Ventilation

Ridge soffit vents importance of balanced roof ventilation.

Best practices attic ventilation.

For both attics and cathedral ceilings roof ventilation works best when it is balanced between high and low to take advantage of natural convection figure 2 55 at left. Throughout the balance of this digest the terms attic and roof will and can be used interchangeably. Warm air that escapes living space also carries moisture that will condense on rafters or roof sheathing. Do not use mechanical means electric attic fans.

As a certified licensed home inspector it is not correct to say too much ventilation is bad for an attic unless rain moisture is getting in. The international residential code irc provision for attic ventilation requires a ratio of one square foot of net free open ventilation area for every 150 to 300 square feet of attic square footage. If you see dampness or frost you need better roof ventilation and some attic vents. As discussed in best practices guide to residential construction chapter on best roofing practices.

For the best results place roof ventilation near the roof s peak and soffit vents in the eaves. Venting a homes attic is a very important best building practices will say 50 at the ridge and 50 at the soffits unobstructed.