Hurricane damage to a house: a structural checklist from the roof deck to the foundation

Hurricane damage to a house comes from wind pushing and lifting on the building, from debris the wind throws, from storm surge and waves, and from rain, and the structural question afterwards is whether any of that reached the frame. Missing shingles are damage to a covering; missing roof decking, trusses lifted off the walls or a fallen gable end are damage to the structure, and this checklist is for telling the two apart.

It is written for owners, builders and agents looking at a building in the days after a storm. It stays inside structural scope: roof coverings, leaks, and mechanical and electrical systems are outside it. Where the damage is structural, the repair needs a defined scope before it can be bid or permitted, which is what a repair specification is for.

What damage a hurricane can cause

The National Hurricane Center rates hurricanes by maximum sustained wind alone, and says in terms that its scale does not take into account storm surge, rainfall flooding or tornadoes. Its damage descriptions for well-built framed homes are a useful map of where wind damage moves as speed rises:

• Category 1, 74 to 95 mph: damage to roof, shingles, siding and gutters is possible.
• Category 2, 96 to 110 mph: major roof and siding damage.
• Category 3, 111 to 129 mph: major damage or removal of roof decking and gable ends.
• Category 4, 130 to 156 mph: loss of most of the roof structure and some exterior walls.
• Category 5, 157 mph or higher: a high percentage of framed homes destroyed, with total roof failure and wall collapse.

The progression is the point. Damage begins at the covering, moves to the deck and the gable ends, and then to the framing and the walls. A house that lost only its covering is in a different class of repair from one that lost its deck.

Water is a separate threat with separate damage. The center's hazards page says storm surge and large waves pose the greatest threat to life and property along the coast, with buildings destroyed and beach and dune erosion among the results, and that flooding is the major threat for people living inland. It also notes that debris such as signs, roofing material and siding becomes flying missiles.

Why the damage follows a path

FEMA's wind retrofit guide defines load paths as chains of connections that transfer loads from where they are applied to the foundation. Its coastal construction fact sheet on load paths lists the links: roof covering to sheathing, sheathing to roof framing, roof framing to the bearing walls, upper walls to lower walls and the floor, and the floor to the foundation.

The same fact sheet explains why damage spreads. If a connection fails, an alternative load path forms and the adjacent framing receives more load, and if that new path is too weak, progressive failure can occur. A storm that pulled one truss off a wall has put more load on the trusses beside it, whether or not they show it.

FEMA's guide records what that looks like after real storms. It reports light-framed wood trusses lifted off exterior walls, which enabled gable end walls to collapse, and it notes that a broken window or glass door can let wind pressure build inside a house, which may cause structural damage. Older buildings that performed poorly, it says, often lacked a continuous load path for gravity, uplift and lateral loads.

The checklist, from the top down

Work from the outside first and from a safe distance. A roof with displaced framing or a wall out of line is not a place to stand while documenting it. Photograph each item before anything is moved, because the department's guidance for association policyholders after a storm is to take photos and video of damage and to keep receipts for temporary repairs.

Roof deck

• Sheathing panels missing, displaced or lifted at their edges, as distinct from shingles or tiles missing over intact sheathing.
• Daylight visible from the attic through the deck.
• A ridge or eave line that is no longer straight when sighted from the ground.

Roof to wall connections and gable ends

• Trusses or rafters lifted from the top of the wall, visible in the attic as a gap at the bearing point or as bent or pulled connectors.
• A gable end wall leaning out of plane, cracked at its base, or gone.
• Soffits torn away, which exposes the roof framing and the attic to wind and water.

Openings

• Broken windows or glass doors, and garage doors pushed in or pulled out of their tracks. FEMA's guide names unprotected openings, garage doors and soffits among the features of older buildings that performed poorly.
• Damage on the leeward side of the house or to interior ceilings near a breached opening, which can follow a rise in internal pressure.

Walls

• A wall out of plumb, or diagonal cracking at the corners of openings, either of which can indicate racking under lateral load.
• Separation between an upper story and the story below, or between a wall and the floor it sits on.
• Impact damage from trees or debris that reaches the framing rather than stopping at the siding.

Foundation and the ground under it

• Erosion around or under the foundation after surge or flooding, and on piled houses any pile that is cracked, displaced or no longer bearing.
• Floors that have moved, doors that no longer close, or new cracks in a slab after water has stood around the house.
• Debris lodged against or under a house on piles, recorded where it lies before it is cleared.

Any yes on that list is a structural question. Whether a foundation has moved is a measurement rather than a judgment by eye, and a foundation inspection records floor elevations so the answer rests on numbers.

Temporary repairs, permanent repairs and the certificate

Temporary repairs come first and are expected. The department's COAST program sheet lists boarding up broken windows and doors and removing standing water among them, and the association's certification page lists temporary repairs after a storm among the work that needs no windstorm certificate.

Permanent repairs inside the catastrophe area are another matter. Section 2210.2515(a) of the Insurance Code defines an improvement to include repair, and subsection (b) requires written notice to the department before the work begins. A storm repair finished without that notice and without inspection while it was open can leave the house unable to be insured through the association until the repair is certified after the fact, which section 2210.258(b) and the completed construction route make slow and evidence heavy. The coastal repair sequence is on the re-roofs and repairs page.

A repair also opens connections that are otherwise covered, which makes it the practical moment to look at the load path. FEMA's guide organizes wind retrofits into three successive packages, Basic, Intermediate and Advanced, addressing roof and wall coverings, openings and load path connections, and says they correspond to the IBHS FORTIFIED Roof, Silver and Gold designations. Whether any of that is required for a given repair is a question of the adopted code and the scope, not of the guide.

When the damage needs an engineer

Covering damage over a sound deck is a roofing repair. A lifted truss, a displaced deck, a leaning wall or a moved foundation is a structural repair, and a structural repair needs somebody to say what failed, what has to be replaced and how it is to be reconnected. An engineer's sealed opinion on cause and extent is a different document from a windstorm inspection and from a certificate, a difference set out on the inspection versus forensic report page.

Where the question is insurance rather than structure, which policy answers which part of the damage is covered on the hurricane damage and insurance page. On the Coastal Bend, where Hurricane Harvey came ashore near Rockport in 2017, the region's building departments and windstorm requirements are summarized on the Coastal Bend coverage page. Where a building department or a lender needs a sealed statement that a repaired element is adequate, that is the purpose of a structural letter.