Free light in a building is an excellent way to reduce energy costs in any type of building and have been utilized on commercial buildings very effectively.
The earlier skylights were metal steel frames with reinforced glass, usually clear. These were very simple in design and water tight. However, when the inside tracks of these skylights filled with dust and dirt and were not cleaned out they would leak. The inexperienced common remedy was to apply sealants or tars to the outside metal frame subsequently ruining the skylight. The simple maintenance aspect wasn’t understood by those who tarred them and this usually resulted in a very expensive skylight being replaced. Though the construction and design of these older units was very good, the clear glass could make it very hot inside and not very energy efficient.
Later came fiberglass and resin skylights. These are normally 4 ft by 8 ft in size and have a single layered dome. They are inexpensive and do let in light but are not very energy efficient. Due to the resin that is used, the light is a yellowish color. These skylights last and hold up well but over time start to deteriorate. After 15 to 20 years or more the surface resin which is exposed to the sun starts to decay and expose the fiberglass strands in the resin weakening the skylight and eventually causing leaks. The domes can be replaced fairly inexpensively or the surface can be clear coated with specialized coatings made for this purpose to get more life out of them. Some of these resin skylights will be on metal frames with stationary side louvers to help with building ventilation as well as light. This type of venting skylight can leak from rain splashing up and into the louvers.
Some skylights are just mounted on wooden curbs with the roofing membrane covering the exterior of the curb.
More modern skylights are made using plexiglass. These domed skylights come with a single dome or double layer of plexiglass with different colors of glass to choose from. They can be bought to go over a pre-existing curb or with a complete built in curb. All skylights can be ordered to any size. For the most part, they are standardly sized from small to large with any odd size needing to be custom made.
When choosing your skylight check the energy star rating it has or its energy efficiency. You should also check how much light it will allow in. This is gauged by how high your ceiling is.
There are many skylight manufacturers out there and more information you can gather to determine what is best for your building in terms of lighting, efficiency and cost.
Commercial Cool Roof Systems can provide you with skylight work ranging from repairs to existing skylights to full skylight installations including roof cut out, structural reframing, curbs with all water proofing and installing the skylight dome.