Large glass openings — sliding walls, bi-fold doors, lift-and-slide systems — are popular precisely because they open a home to the outdoors, but in California they also have to satisfy two separate sets of requirements: Title 24 energy performance and local seismic design rules. Here's what each actually covers.
Title 24 sets energy-efficiency requirements for buildings in California, and for glazed openings that generally comes down to thermal performance — how much heat the glass and frame let through (U-factor) and how much solar heat gain the assembly allows (SHGC). Thermally broken aluminum frames, like our W62/W72 window and door system, are designed around this requirement by separating the interior and exterior metal with an insulating barrier rather than running aluminum straight through, which is a major factor in meeting Title 24 performance targets on a large glazed wall.
The specific numbers your project needs to hit depend on your climate zone, the rest of your building envelope, and whether you're doing new construction or a retrofit — your installer or a Title 24 energy consultant will run the calculation (CF1R) specific to your project rather than relying on a generic product spec sheet.
California building code requires structural systems — including large glazed openings that carry their own weight and wind/seismic load — to be engineered for the specific site and building. A wide sliding or lift-and-slide system like SL160, or a multi-panel folding system like BF73, needs its header, jambs, and anchoring reviewed against your project's actual structural conditions rather than assumed from a catalog spec. This is typically handled through project-specific structural calculations submitted with your permit application.
In short: the system itself (frame design, glazing type, thermal break) is engineered by the manufacturer to a high baseline, but the project-specific compliance — the Title 24 energy calc and the seismic/structural calc — is typically handled locally, by your installer, architect, or a licensed engineer, as part of your permit submission. When you request a quote from us, it's worth asking early whether your project will need either calculation so it can be scoped into your timeline from the start.
We can provide the technical specifications your energy consultant needs (U-factor, SHGC, frame details) for the products you select; the formal CF1R calculation is typically completed by a Title 24 consultant or your architect as part of permitting.
Most permanent structural glazing in California does, though requirements vary by jurisdiction, span size, and whether it's new construction or a replacement in an existing opening. Your local building department will confirm what's required for your specific permit.
A standard sliding door rolls on a track at floor level. A lift-and-slide system lifts the panel slightly off its seals before sliding, which allows much larger and heavier panels to move smoothly and seal more tightly when closed.
Not universally required by name, but the thermal performance they provide is often the most practical way to meet Title 24 targets on a large aluminum-framed opening, especially in colder California climate zones.
