Questions covered in this guide
First identify the attic assembly
For a vented attic, GAF describes a system with intake and exhaust working together. Its guidance warns that incompatible exhaust arrangements can upset that plan. Ask your roofer to identify the existing assembly before recommending changes. Do not assume a vented-attic approach applies to every roof or add vents to an unvented design based on this worksheet.
Ask for a simple marked plan
Request a sketch showing where air is intended to enter and leave, which existing vents remain and which would be changed. The sketch is a communication aid; the contractor remains responsible for the project design and applicable requirements. Ask them to explain any obstructions or disconnected attic areas they find, without asking you to climb onto the roof or enter an unsafe space.
Compare more than a product name
Put one row on the bid sheet for intake work, one for exhaust work and one for any associated changes. Ask what measurements and product ratings support the proposed arrangement. A line reading ridge vent included does not describe the intake side or tell you what happens to existing vents. Require each bidder to mark exclusions and resolve differences before comparing the total.
Keep the budget honest
The roofing calculator uses a broad shingle-installation reference. It does not design attic ventilation or price every alteration to soffits and other components. Use the contractor’s documented additional scope without adding it twice if it is already included in the total. Ask who will provide completion photos or a final explanation of the installed arrangement. Keep that record with the roof warranty and proposal so future work can account for the system already in place.
Putting it into practice
The marked plan and three scope rows make intake work visible alongside exhaust products. The guide explicitly limits its discussion to vented attics and does not substitute a national vent ratio for project design.
Sources and supported claims
GAF’s vented-attic guidance calls for a coordinated intake and exhaust arrangement.
Source ↗ · national · Checked 2026-10-12
GAF warns against mixing incompatible exhaust types in the same attic space and recommends professional planning.
Source ↗ · national · Checked 2026-10-12