Commercial polycarbonate windows from Extech undergo lab testing with 2x4s.

In the two years since Hurricane Katrina walloped the Gulf Coast, a surge of new impact-resistant product lines from door and window manufacturers has been taking commercial and residential building markets by storm. Manufacturers say demand for storm-proof windows has ratcheted up in coastal areas from Texas to New England, with 18 states now implementing tougher building codes in the past two years.

“Building inspectors are looking at things much more carefully in coastal areas in the Northeast,” says Ebrahim Nana, president of Mill Valley, Calif.-based Nanawall Systems, a manufacturer of exterior sliding wall systems. Its SL72 folding glass-wall system meets Miami-Dade County, Fla.’s high-performance standards, but new code standards as far north as New York prompted the company to add a new product line this year.

Windows with vinyl frames offer better thermal ratings than aluminum.

The new  SL70 product (shown  right), has an added a 3⁄4 in. polyamide plastic thermal break in the windows’ aluminum frames to provide better thermal protection. “We were getting requests from clients in the northern coastal areas for this type of product, “says Nana. “It is a high-performance glass-wall system that offers better energy efficiency.”

Cellular polycarbonate, a window material traditionally limited due to its propensity to discolor over time, is becoming more popular as manufacturers make improvements to reduce discoloration while retaining high strength.

Pittsburgh-based Extech Exterior Technologies Inc.’s Protechtor window series employs a high-strength, low-discoloration polycarbonate resin the company began developing “shortly after Hurricane Andrew,” says Bill Voegele, president of Extech and Voegele Co. Inc., the parent firm. “Early experiences with polycarbonate windows were not very positive. But in the new polycarbonate materials we’ve developed, we have added ultraviolet absorbers into the resin, giving it a 30-year life before discoloration. It’s made polycarbonate a viable product.”

As tougher storm codes move north, demand is growing for vinyl-framed storm-resistant windows, which offer better thermal ratings than aluminum-framed windows. “Vinyl is on the rise,” says Chris Monroe, vice president of marketing for Parkersburg, W. Va.-based Simonton Windows. “We are phasing out aluminum frames this year.”

Simonton’s StormBreaker Plus vinyl windows and doors meet a design-pressure rating of 50.