What are attic baffles and what do they do?

Attic baffles are rigid channels installed in each rafter bay at the roof eaves. They hold insulation away from the soffit vents, keeping a clear airway between the insulation and the roof deck so ventilation can flow from intake to ridge.

Are attic baffles required by building code?

Yes. IRC Section R806.3 requires a minimum 1-inch clear airway between insulation and the roof deck at the eaves. Missing baffles in a vented attic assembly are a code violation.

Can I add insulation without installing baffles first?

Adding insulation without baffles in a vented attic blocks soffit intake and stalls the entire ventilation system. Always install or verify baffles before adding any blown-in or batt insulation.

Do all attics need baffles?

Vented attics with soffit and ridge vents require baffles in every rafter bay. Unvented attic assemblies using closed-cell spray foam applied directly to the roof deck do not use baffles and should not have them installed.

How do I know if my baffles are working?

Check from inside the attic with a flashlight. Each rafter bay near the eaves should show a visible air channel between the insulation and the roof deck. No visible gap, crushed baffles, or insulation packed to the sheathing all indicate the baffles are missing or failing.

Attic Baffles: Why They're Crucial for Ventilation & Installation Guide

Home inspector installing attic baffle in attic

Here are recommended resources for attic ventilation and insulation: Attic Ventilation – The Attic Genius, Attic Insulation Mistakes DIY Homeowners Must Avoid, What Is Convection in Attics: A Homeowner’s Guide, and What Is an Attic Air Barrier and Why It Matters.

Attic Baffles: Why They're Crucial for Ventilation & Installation Guide

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