Should You Tornado-Proof Your House?

Man installing interlocking metal shingles Interlocking steel shingles are one way to reinforce your roof against tornado damage. Image:

Here are six ways to tornado-proof your home. Warning: These aren’t cheap — nor foolproof — methods.

Ever been awakened by a tornado siren in the middle of the night? It’s plenty scary — tornadoes move fast and can tear apart your house in seconds.

To keep you and your family safe, the best defense is a tornado storm shelter — a rugged safe room or pod you can scurry into if there’s a big storm.

But there are other measures you can take to strengthen your house and prevent costly damage. These aren’t simple fixes — most involve major retrofit projects — but they might make sense if you’re planning a substantial remodel, such as replacing your roof, windows, and doors.

They’ll add to the cost of your project, but if you live in a tornado-prone area, you can probably justify the extra 20% or so premium expense for these beefier methods and materials.

Here are 6 tornado-proofing ideas suggested by our friends at Safer, Stronger Homes.

1. Extra fasteners for roof sheathing

The risk: Winds tear off roof sheathing, exposing the interior of the house to damaging rain and debris.

Fix: Use ring-shank nails or screws to fasten plywood sheathing to roof rafters. Use tighter nail spacing than required by code (typically 6 inches apart). Careful nailing is a must, especially at the edges of sheathing panels.

Cost above conventional practice: $450 (average)

2. Seal roof sheathing seams

The risk: Winds lift off underlayment (the protective layer directly below shingles), exposing joints in the roof sheathing.

Fix: Seal sheathing joints with bituminous peel-and-stick flashing tape. Cover sheathing with self-adhering membrane roofing underlayment (as opposed to traditional roofing felt).

Cost above conventional practice: $800-$1,200 (average)

3. Install wind-resistant roofing

The risk: Winds destroy roofing, your house’s primary defense against water damage.

Fix: Install a roofing type that exceeds wind ratings for your region:

  • standing seam metal roofing
  • heavy clay or concrete tiles
  • asphalt/composition shingles rate either Class G (120 mph winds) or Class H (150 mph winds)

Cost above conventional practice: $1,000-$3,000 (average)

4. Use wind-resistant siding

The risk: Even minor damage to siding can let moisture inside walls, where it can lead to mold and rot.

Fix: Use wind-resistant siding products that are nailed directly into wall studs, not simply into the wall sheathing:

  • vinyl siding should be rated to withstand 150 mph winds and feature a double nailing hem
  • fiber-cement siding is extremely heavy and wind-proof

Cost above conventional practice: $1,000 (upgrade vinyl) to $15,000 (all-new fiber-cement siding)

5. Add impact-resistant windows and doors

The risk: Windows and doors break or blow open, letting in rain and destructive winds that can lift off roofs.

Fix: Install impact-resistant windows and doors rated for winds at least 30% stronger than demanded by local building codes. Install out-swinging windows (casements) and exterior doors so that wind pressure tends to compress seals. Avoid double-swinging windows, doors, and sliders unless they are rated for high wind resistance.

Cost above conventional practice: 2-3 times more expensive per unit than comparable conventional windows and doors

6. Install wind- and rain-resistant roof vents

The risk: Roof vents are designed to exhaust hot, humid air from attic spaces, but they are weak points during storms with high winds, letting rain water inside your house.

Fix: Replace vents with wind- and rain-resistant models.

Cost above conventional practice: $1,000 replacement cost (average)

Have you ever been close to a tornado? Did you modify your home as a precaution?