When Hurricane Irma hit south Florida last September, residents and business owners braced for the worst. Packing 130 mph winds when it made landfall in the Florida Keys, Irma caused widespread damage on both the Gulf Coast and in the Miami area, where fierce winds toppled construction cranes and pushed water through window seals and roof joints at Miami International Airport.

Despite the risk presented by megastorms like Irma, homeowners in coastal areas are demanding floor plans that open their homes to the elements. Manufacturers have responded with opening glass wall systems that provide architectural appeal and indoor/outdoor flow. Here are six key features architects and builders should look for in glass wall systems to ensure performance, even in the next big storm:

  1. Reinforced structural posts: Look for a folding glass wall system with reinforced vertical posts (or astragals) down each panel side for added performance. This design means that instead of the glass walls pivoting on rollers with ball bearings, they pivot on and are hinged to either side of the vertical post. The post itself should have stainless steel wheels that are connected to a track—just like the wheels of a train—and therefore run along the track without pivoting. These reinforced vertical structural posts provide incredible strength against high winds and water blowing against the system.
  2. A floor-supported system: Many glass wall systems are hung from a top support and only use a floor rail to guide the panels’ path. But heavy, moveable panels require an incredibly strong header and, if not, the glass walls are more susceptible to high winds. Floor-supported systems, on the other hand, use gravity to their advantage with all of the weight supported on the floor. This extra stability further enables the glass wall system to withstand hurricane force winds.
  3. Raised sills: Extreme weather means that water, mud and other particulates will be pressed up against the glass, seeping in through the floor tracks and ruining wood and carpet. A high-performance raised sill is the most weather-resistant sill out there and prevents both static and dynamic water penetration, also yielding higher pressure ratings against heavy wind loads. This means that even without an overhang to shield from the elements, the glass walls can squarely face even the strongest winds.
  4. Corrosion resistance: This goes without saying. Not only do you need extruded aluminum frames and panel profiles (an absolute must when it comes to protecting against the saltwater-filled air), but make sure the rollers and hinges themselves are stainless steel. When you have salty wind and rain beating up against a system, the parts can quickly rust and corrode, weakening its performance against future storms.
  5. Multipoint locking: Vandalism and burglary is a real issue once residents have been evacuated, leaving their homes and businesses unprotected until cleanup efforts are under way. Looters will usually look for easy points of entry, often breaking in through sliding or folding glass walls. A latch and deadbolt isn’t enough. Look for a multipoint locking system that also includes top and bottom locking rods so that each glass panel can be securely locked into the upper and lower frame with polyamide capped locking rods. This is paramount when securing the opening, and it also adds to the glass wall’s ability to withstand strong winds and water intrusion.
  6. Additional certifications: Ratings for Miami-Dade, ANSI (American National Standards Institute) and ASTM (American Society for Testing and Materials) are just the base line. Builders who use glass wall systems in hurricane country should consider products that adhere to climate performance and durability, such as AAMA (American Architectural Manufacturers Association) rated for air, water, structural and forced entry; as well as NFRC (National Fenestration Rating Council) certified for air leakage and condensation resistance.