Retrofitting Your House for a Hurricane: The Roof
Can your roof protect your home against a hurricane?
If you live in a hurricane prone environment, consider upgrading to a hurricane-rated roof system or having a roofing contractor improve your current system.
Regardless of the roof surface used, the most important aspect of the roof is its structural frame and sheathing. Wind driven uplift is the roof’s biggest threat.
Understanding roof terms
A typical rooftop is made of (in order from innermost to exterior):
- a frame of wooden rafters (also called ‘chords’) that form a triangular truss, joints and beams as a foundation
- a layer of sheathing that covers the entire surface above the frame
- underlayment (usually back felt paper) which is water-resistant and helps any penetrating water run off the rooftop
- a covering, usually of shingles or tile, which shields the other layers from sun and other weather
Evaluating Your Roof
Even if you don’t have a hurricane-rated system, it’s important to maintain your roof. Even the best roofing materials will eventually degrade and need replacing, which will happen faster if it’s exposed to high heat and strong winds.
Examine your rooftop routinely for damage, using binoculars to get a better view. Climbing on the roof will risk damaging the shingles or roofing material, so if you can’t see from below, try propping a ladder up and viewing from there. Look for any exposed sections of underlayment or sheathing.
Small holes, like nail holes, can be easily repaired with roofing cement. It doesn’t take much cement to repair a hole, and it can be stored long-term, so you should keep some in stock.
Be sure to read the instructions, as different cements need more pressure or certain surface types to adhere properly. A tool to push it down and into cracks will help. Always try scraping it off once it dries to be sure it stuck to the surface.
Repairing Shingle Roofing
For shingles that are cracked, first consider the location: broken shingles on an overhang may not need immediate attention, but those over the attic will.
Some building codes don’t force you to replace broken shingles completely, but you should. Adding new shingles over the top won’t be as secure, and it won’t give you a chance to check the sheeting below.
If you do need to replace the roofing, take the opportunity to check the fasteners atop the exterior. They’re hard to see from the inside, but if you remove the sheathing, you can ensure the roof is fastened with proper hurricane-grade clips (even if you have to add them yourself). It’s common to “toe-nail” the top simply by nailing in the roofing materials, but this isn’t effective in heavy winds.
The shingle bonding is also crucial, but difficult to check. Have a professional regularly check the adhesive to see if weather conditions have weakened it, and reinforce the bond with asphalt cement for a strong hold. Don’t bend them too far when you lift them to insert the cement, and be sure to get each individual one.
Broken tiled rooftops can be especially problematic, because in addition to creating a potential leak point, the tile itself can become a projectile in high winds.
Tile can be securely attached with adhesive foam, which adds an extra layer of leak protection, or with concrete. Concrete is sometimes used decoratively, so don’t assume your tiled rooftop is secure if you see concrete on the outside. Concrete is also very prone to weather damage, and needs monitoring.
Generally, the tiles most sensitive to damage are the least likely to cause a leak, but damaged tile always poses a threat, so keep up with repairs.
Most rooftops slope. The triangular peaks created by this are called gables. The triangular section of wall that connects the home’s walls to the roof is called the gable end wall.
Gables are a particularly vulnerable point in a roof. They can also be easily reinforced. Add braces at least every 4 feet to the gable end wall and reinforce the connecting points with the wall with special hurricane clips. Braces along the ridge of the roof peak also add strength.
The most damaging thing that can happen to your home is that the roof will be removed, often resulting in a total collapse. Reducing the upward forces on your roof can help keep it in place to protect your home’s structure and interior.
Reinforcing connection points helps strengthen the home against uplifting forces. The roof deck (think of this as being the floor of an attic) can be reinforced three-fold by applying wood blocks to hold the deck to all of the roof frame elements. Simply attach the corner of the blocks with caulking firmly to both pieces at their connection point.
Be prepared and make sure your roof is in the best shape possible before the next hurricane.
More home hurricane advice for: