Here at VELUX, we're a little bit on the goody-goody side. We're all about staying in line with state- and nation-wide building codes and regulations in regard to our skylights.
For one reason, it allows us to stay in business. For another, it ensures the homes and buildings that feature our skylights stay structurally sound as well as energy efficient.
In California, the building codes are written into a bit of legislation called Title 24. And there are a few exceptions in there regarding skylights and other types of fenestration you'll want to make sure you're up to date on.
If you're working in California, you may already be familiar with Title 24. But just to make sure everyone's up to speed, Title 24 of the California Code of Regulations (a.k.a. the California Building Standards Code a.k.a. Title 24) contains the regulations that govern the construction of buildings in California.
Among these regulations are the California electric, mechanical, plumbing, and energy codes as well as codes for working with existing and historical buildings and codes for complying with green building standards.
If you go through these codes, you'll find general building design and construction requirements relating to fire and life safety, structural safety, and access compliance. These provisions also provide minimum standards to safeguard life or limb, health, property and public welfare. These minimum standards are met by regulating and controlling the design, construction, quality of materials, use and occupancy, location and maintenance of all buildings and structures, as well as certain equipment.
If you'd like more information on the specifics of these codes, you can visit the California Building Standards Commission (CBSC) website then click "CODES."
In order to ensure you're compliant with Title 24, you must assess your work through one of two methods:
According to Title 24, a skylight is defined as "a fenestration installed on a roof less than 60 degrees from the horizontal" and the skylight type must be either glass mounted on a curb, glass not mounted on a curb, or plastic (assumed to be mounted on a curb).
In the codes, skylights are addressed in conjunction with other types of fenestration, like vertical windows and glass doors. It establishes rules for implementing them, as well as their labeling and certification, as they relate to
All of these rules for implementation are to ensure that not only is the building structurally sound, but that it's also as energy efficient as possible.
Title 24 actually has many exemptions built into its codes, but there's one (well, really, four) in particular that affects fenestration and skylights that we'd like to focus on.
According to Title 24, only a certain percentage of any given building may feature fenestration, or windows and doors on its elevations. For example, the maximum total fenestration area of a building, including west-facing skylights tilted in any direction when the pitch is less than 1:12, cannot exceed the percentage of conditioned floor area. This is because when fenestration exceeds the set amount, the building not only becomes less energy efficient, but is also not as stable or equipped to withstand natural disasters.
Additionally, the area weighted average U-factor and SHGC requirements of the initially installed fenestration products is outlined in Title 24's TABLE 150.1-A, along with Sections 110.6(a)2 and 110.6(a)3.
In these sections, Title 24 also outlines the exceptions to these codes:
The main exceptions concerning VELUX and VELUX installers are the first two, regarding additional tubular and regular skylights.
The first one says, in many more words than necessary, that you can add up to 3 square feet of new sun tunnel skylights without regard for the normal U-factor and SHGC requirements.
The second one says that, in existing buildings, up to 16 square feet of new skylights can be installed, even if the typical fenestration limits have already been reached, so long as the newly installed skylights don't exceed an U-factor of 0.55 and a SHGC of 0.30. And don't worry: VELUX does offer skylights that meet these restrictions.
Remember those Title 24 assessment methods we talked about earlier? They're coming back into play. If you're utilizing the Title 24 prescriptive method to verify compliance, you won't need to receive approval to utilize these exceptions. However, if you're using the Title 24 performance method, you will need approval from the energy engineering group certifying the structure.
So, as you can see, these codes and exceptions are important to know about when you're installing skylights and sun tunnels in California! If you have any questions regarding Title 24, you can find more information by contacting your regional DSA office directly.