Installing skylights in a commercial or residential building brings a taste of the outdoors in and brightens up the environment with natural light. In an energy-efficient steel building, the addition of a skylight enhances its sustainability while adding to the beauty of the structure.
When selecting skylights, there are several options and styles, one of which best fits your needs. Skylights are available in different materials that provide a variety of thermal and lighting solutions from providing diffuse lighting to providing a heat source.
The Benefits of Skylights
Skylights are an attractive and pragmatic alternative to electric lighting and add an ambiance not matched by windows.
- Skylights can prevent heat loss or allow more heat to be transferred to the interior.
- Skylights can reflect heat while letting in light.
- Skylights increase comfort and visibility and have options to control the amount of light that enters.
Without skylights, it would be difficult to design a green structure without requiring the occupants to operate in less than adequate lighting. People working in offices are typically more productive under natural light and retail sales tend to increase with the use of skylights.
Skylights also reduce the need for electrical lighting and heating, reducing your energy bill. Many skylights are designed to allow the amount of light entering the building to be controlled. Furthermore, many skylights can last for 30 to 50 years before they must be replaced.
Types of Skylights Available
The use of the building and the local building code may dictate the type and number of skylights installed. Common types of skylights are light transmitting panels (LTPs) and curb mount skylights.
The transparent lens of a skylight can be made of different materials including glass, fiberglass, acrylic, polyvinyl chloride (PVC) and polycarbonate.
Polycarbonate is one of the newer skylight materials to be introduced to the market and as its popularity grows, the price continues to decrease. It's now relatively equivalent in price to other materials.
- Polycarbonate is nearly unbreakable.
- It remains clear throughout its service life.
- It has a longer lifespan than fiberglass.
- Polycarbonate is easily recycled.
Although polycarbonate is a durable material, glass typically comes in first for the longevity of use without yellowing or degrading in the sun. However, polycarbonate expands and contracts more in the heat than metal. When installing, the contractor may wish to increase the size of the fastening holes to allow for the added movement. For example, a 10-foot sheet of polycarbonate can expand up to one-quarter of an inch.
Fiberglass skylights have undergone improvement over the years, including the addition of a reinforced polymer face sheet to increase durability. Fiberglass is more prone to cracking than polycarbonate and the face sheet allows the vendor to allow a longer warranty.
- Fiberglass skylights can last twice as long as polycarbonate multi-wall panels.
- The longest lasting material is glass.
- After 20 to 25 years the glazing and sealants will require repair and replacement but if repaired can easily last another 25 years.
Skylights can be designed in a variety of ways to create a lighting scheme that works for the occupants of the structure. With the right glass or other material, skylights can diffuse light rather than create hot spots on the floor. Other skylights can be designed to let in light without overheating the interior of the building.
Extremely large skylights are created by bolting a steel frame directly onto the roof system. You see these in shopping malls and certain large office buildings or hotels. Skylights are available that are fire and hurricane rated as well.
Considerations When Selecting Skylights
As with insulation, the climate should be considered when selecting a skylight. Keep in mind the local weather patterns. Some types of precipitation can get rather noisy, such as hail and hard rain. Noise dampening options are available. Areas with copious snow and ice can also cause problems with skylights including leaking and creating ice dams if not installed correctly.
The best time to install skylights is when the roof is installed. The contractor can then create custom penetrations to fit the skylight and install flashing before laying the roof panels. Make sure the selection of the skylight is compatible with the metal roof system on the building.
The ratio of skylights to roof depends on the desires and needs of the occupants. Skylights could cover nearly an entire roof or can be strategically placed to send light into dark interior sections such as hallways. The orientation and location are important in determining how much light will enter the building. Skylights on the southern side of the roof will have light most of the day and provide added heat during the winter months. Westward oriented skylights may provide too much heat in summer, increasing the load on the air conditioning.
Another factor in selecting skylights is the R-value, its thermal performance. The R-value is often determined by the thickness of the panel; thicker panels yield higher R-values. Other products can be used to increase the R-value as well, such as insulating a multi-wall panel with flutes in the middle.
Finally, before you order skylights, check the spanning capability, impact strength, UV protection and warranty. The vendor should be able to provide that information.
One process of installing a skylight is similar to installing a steel panel. One-quarter inch, pre-drilled fastener holes are placed in the overlapping ends and sides. Once the panels are bolted into position, the holes around the fasteners are treated with a waterproof sealant to prevent drafts, water leaks or excess heat transfer.
Avoid walking onto a skylight pane or placing body weight on the surface during installation or maintenance. Such actions can result in cracks in the panel. Safety netting will be required either on top or below the installed skylight.
Ongoing efforts to decrease energy use and improve the indoor environment is driving the sale and installation of skylights. Beyond their practical benefits, skylights can also increase the value of a home or other property, providing a return on your investment.
According to the Office of Environment and Heritage and the Whole Building Design Guide, properly located and oriented skylights can shave up to 80% of the cost of lighting and reduce overall energy costs by 33%.
To save energy while increasing productivity, consider installing skylights in your current building or including them in your next project.