To accommodate the industry-standard roof hatch width in these rare applications, OSHA has permitted the use of adding a deflector plate at the point where any obstruction reduces the 37-inch dimension. The deflector plate is defined within the Standard and is typically not provided by the roof hatch manufacturer.

Custom Options

In addition to the options already discussed, roof hatch manufacturers offer more options to customize a product to suit a particular application without compromising features or performance. Some additional custom options include:

Curb options can simplify installation on various roof systems. Roof hatches can be supplied with curb liners or fully enclosed curbs for installation on existing curbs. Curbs can be modified to be installed directly on standing-seam metal roof panels. This modification allows a hatch to sit directly on a metal roof, eliminating the need for a job-built curb.

Hatches can be specified with a polycarbonate dome cover to provide the added benefits of a skylight. The cover allows natural light into a building, possibly reducing energy costs and providing a more pleasant building environment.

Louvers incorporated into the hatch curb provide continuous, passive ventilation into a building.

Special finishes are available from hatch manufacturers for added corrosion resistance or to allow a hatch to match a building's exterior. Common finish options include anodized aluminum and paint finishes such as Kynar, Tnemec, and powder coat paint.

Photo courtesy of Jenn Bakker/Breathtakingmomentsphotography.com and The BILCO Company

A roof hatch with fixed-ladder access.

Thermally Broken Roof Hatch

Thermally broken roof hatches (frame and cover) are designed to minimize heat transfer and the effects of condensation. Depending on the manufacturer, they may feature up to R-20 or greater insulation and a frame and cover design that minimizes heat transfer between interior and exterior metal surfaces.

Here are some typical features of thermally broken hatches and their benefits:

• Thermally broken covers and curbs reduce heat transfer between interior and exterior surfaces to resist harmful condensation.
• When used, ozone-friendly polyisocyanurate insulation (R-20+) provides superior energy efficiency.
• Superior gasketing enhances weather and wind resistance.
• May meet LEED® standards for recycled content.
• Possible high solar reflective index (SRI).
• The components may dampen vibration for improved acoustic performance against outside noise.

Rooftop Deck on Cape Cod Residence

An excellent example of a custom roof hatch can be found on a home in Scituate, Massachusetts, where a thermally broken roof hatch allows for energy efficiency as well as breathtaking ocean views.

Growing up on Cape Cod in Massachusetts, builder PJ Antonik knew rooftop decks are highly coveted by residents who yearn for views of the nearby Atlantic Ocean. What the builder did not realize is how challenging they can be to construct.

Antonik, the founder and CEO of Oak Development Design, and his team constructed a three-and-a-half-story home with a 500-square-foot rooftop terrace. The house's ridgeline sits 40 feet in the air, allowing homeowners and their guests unparalleled ocean views. They access the terrace with a custom-built ladder, passing through a thermally broken roof hatch.

The 3,400-square-foot home is located in a four-unit development, all designed by Oak Development & Design, just one block from Cohasset Harbor. All four homes have roof decks. "This is the only one with a roof hatch," Antonik said. "They will have a wide-open view of the Atlantic, and the sun sets behind you. If you're going to build a three-and-a-half-story home with the Atlantic close by, it's a massive miss if you don't have an ocean view. It's the kind of thing that pushes the potential buyer over the edge to make an offer."

Antonik designed roof access through a skylight-style window accessed by a traditional staircase in three of the homes. Rooftop access for the final house came right through the center of the roof. "We had to do an internal custom ladder, and I've never done that before," he said. "It was especially interesting to figure out how to frame it."

Antonik deliberated about how to access the roof before deciding on the thermally broken roof hatch, which measures 48 inches by 32 inches. "I wanted to keep it to a very low profile, so we mounted it on the framing down on the rubber roofing and framed around it, so it's not sticking way up on the roof. It sounds easy, but it was actually pretty complex, especially never having done it before."

Antonik said he tried other roof hatch models but found them hard to open. The selected hatch was specified for its superior energy performance and because it is easy to open and close. The hatch features counter-balanced lift assistance for easy, one-hand operation and an automatic hold-open arm. The frame and cover design minimizes heat transfer between interior and exterior metal surfaces and delivers year-round energy efficiency. "Roof hatches are hard to find," Antonik said. "This one was easy to install and easy to work with. The thermally broken aspect to it made it a great choice to help reduce energy consumption."

Homeowners with houses close to a body of water enjoy views year-round. However, the architect or builder must creatively design a solution that provides those views. "Every bit of view you can get is really worth it aesthetically," the builder said. "We wanted to capitalize on the beach and the views it can provide, and the hatch made that possible."

Photo courtesy of Lee Cormier and The BILCO Company

Providing access to rooftop decks on residential properties has become an attractive amenity.

STYLES OF ROOF HATCHES AND COMMON APPLICATIONS

As discussed, the specification of roof hatches depends on many factors, including how they will be used. Here are some roof hatch styles and their applications.

Fixed Ladder Access

For fixed ladder access, an easy, one-hand operation to the fully open or closed position is necessary to provide the user the security of having one hand firmly on the ladder at all times. That means a counter-balanced design. Roof hatches are generally available in galvanized steel, aluminum, or stainless steel and can include dome covers for natural daylighting. The standard size of 36 inches by 30 inches may be increased to 36 inches by 36 inches for easier ladder access and to remove or install small pieces of equipment in a building.

Ship or Steep Stair Access

Ship or steep stair access hatches, typically 30 inches by 54 inches (762mm x 1372mm), are helpful for installations where frequent use may be expected. They permit easier movement of maintenance personnel, tools, and equipment.

Photo courtesy of The BILCO Company and Gill Couto Photography

A roof hatch with full-service stair access.