What is roof ventilation, and how much is it?
Short answer. Roof ventilation is the system of intake vents low on the roof and exhaust vents near the peak that keeps air moving through the attic, removing heat and moisture that would otherwise damage the deck and shingles. How much you need is set by code at 1/150 of the attic floor area, or 1/300 when balanced, and its cost shows up on a roofing estimate as a few specific line items.
How ventilation appears on an estimate
- Ridge vent: priced per linear foot, separate from the ridge cap shingles.
- Box or static vents: priced each, often as remove and replace.
- Turbines and power fans: priced each; fans may include electrical work.
- Soffit or edge intake: by the linear foot or each.
- Exhaust caps: bath and kitchen caps, priced each.
- Decking repairs: by the sheet where old vents are removed or the deck has rotted.
How much ventilation you need
Under the residential code, a 2,000 square foot attic needs about 960 square inches of net free area in a balanced system, roughly 480 of intake and 480 of exhaust. The number of vents depends on each product's rating.
Insurance estimates
Claim estimates written in Xactimate list vents individually. If hail dented your box vents, each one should appear; if the roof had a ridge vent, it should appear by the linear foot. Missing vent line items are a common reason for a supplement request.
Why it is worth the attention
Proper ventilation supports shingle life, protects the deck and keeps the manufacturer's warranty intact. Robust Roofing explains how claims handle items like these on its roof insurance claims page. Read roof ventilation basics and how Xactimate roof estimates work.