InterNACHI Wind Mitigation flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Wind mitigation inspection

An inspection that documents wind-resistant features of a building for insurance premium discounts. It is not a home inspection and does not assess code compliance.

OIR-B1-1802 form

The Florida Uniform Mitigation Verification Inspection Form used to report wind mitigation features. Other states may use different forms.

Dynamic pressure formula

q = 0.00256 × V², where q is dynamic pressure in psf and V is wind speed in mph. This shows pressure increases with the square of wind speed.

Internal pressurization

When wind enters through an opening, it increases internal pressure, which can double net uplift on roofs and lead to failure.

Continuous load path

A chain of connections from roof to foundation that transfers wind loads safely. Weak links, such as toe-nailed connections, are common failure points.

Gable end wall vulnerability

Gable end walls are prone to collapse under wind if not properly braced. Look for diagonal bracing or continuous sheathing to confirm reinforcement.

Soffit and fascia damage

Wind can lift soffits and fascia, allowing water intrusion and loss of roof edge support. These are common envelope failure points.

Envelope breach consequences

Breaches in walls or roof allow wind and rain inside, causing internal pressurization, water damage, and potential structural failure.

Impact-rated glazing label

Windows and doors with impact-rated glazing have a permanent label indicating compliance with ASTM E1886/E1996 or Florida Building Code.

Garage door wind rating

Garage doors must be rated for wind pressure and may need reinforcement. Check for a label indicating wind speed rating.

Gable end wall bracing

Gable end walls must be braced to resist wind. Look for diagonal bracing, continuous sheathing, or a structural connection to the wall below.

Roof covering product approval

Roof coverings should have a product approval or evaluation report indicating wind speed rating. This document supports mitigation credit.

Roof covering condition

Missing, cracked, or deteriorated shingles may not qualify for wind mitigation credit. Document condition with photos.

Roof age and permit

Roof age and permit date affect eligibility for certain credits. Older roofs may not qualify; verify permit information if available.

Roof deck attachment methods

Common methods include 8d nails at 6" or 12" on center, staples, or screws. Enhanced attachment with closer spacing or ring shank nails may qualify for better credit.

Nail spacing measurement

Measure nail spacing in the attic with a ruler. Typical spacing is 6" or 12" on center; document with photos showing scale.

Nail penetration issues

Under-driven or over-driven nails reduce holding capacity. Verify that nails penetrate through sheathing and are not angled.

Toe-nailed roof connection

Nails driven at an angle through rafter into wall are the weakest roof-to-wall connection and often fail in high winds.

Roof-to-wall straps

Metal straps that wrap over the rafter and down the wall provide a stronger connection than clips or toe nails. Double straps offer highest credit.

Roof-to-wall inspection

Inspect from attic for straps, clips, or nails at each rafter. Verify connector type, thickness, and nail count; document with photos.

Hip roof advantage

Hip roofs slope on all sides, reducing uplift and often qualifying for better wind mitigation credits compared to gable roofs.

Gable roof vulnerability

Gable roofs have two sloping sides and vertical gable ends, making them more susceptible to wind uplift and gable end collapse.

Roof geometry documentation

Document roof shape (hip, gable, flat) with photos and sketch. Verify all sides are sloped for hip roof credit.

Secondary water resistance material

A layer under roof covering, such as self-adhered modified bitumen membrane, that prevents water intrusion if shingles fail.

SWR coverage requirement

Secondary water resistance must cover the entire roof deck, including valleys and edges, to qualify for credit.

SWR verification method

Verify SWR by lifting shingles at eaves or inspecting from attic. Look for membrane; document with photos showing material and coverage.

Opening protection types

Impact-rated windows/doors, shutters, or panels that protect against debris. All openings must be protected for highest credit.

Shutter labeling requirement

Shutters must be tested and labeled, and must cover the entire opening. Verify proper anchorage and label.

Opening protection documentation

Photograph each opening with protection and label. Note any unprotected openings, which may reduce credit.

Required inspection photos

Photos must include front of house, address, roof covering, deck attachment, roof-to-wall connection, SWR, and opening protection, each dated and labeled.

Photo labeling protocol

Each photo should be labeled with location and description. Take wide-angle and close-up shots to show context and detail.

Documenting limitations

Note any areas not accessible and explain why in the report. This maintains transparency and accuracy.