Field Note · Architectural Glass
Stained glass is an art form, a material specification, and a California Title 24 compliance question. The original Victorian and Craftsman-era leaded panels in heritage homes are mostly single-pane and bleed heat. Modern art glass can be specified to a thermally-broken IGU with the leading still visible. Which path matters depends on whether you are restoring or building new.
By Amy Kunst, M.A. (CSUS), NKBA Committee Member.
Restoring Original Panels
Pre-1940 leaded glass uses real lead came (the H-channel between glass pieces) and real cement (linseed-oil putty between glass and lead). These deteriorate over 80-120 years — the lead loses tension, the cement cracks, the panel sags. Restoration runs $300-$800 per square foot depending on glass-painting work. The panel is removed, dismantled, each piece is cleaned, the lead is replaced, the cement is replaced, the panel is re-leaded and re-installed. Done well, the panel survives another century.
Energy Code Reality
California’s Title 24 requires fenestration in new construction and major remodels to meet a maximum U-factor (typically 0.30 in most CA climate zones). A single-pane leaded panel is around U-0.95 — fails by triple. The solution for new installation is an interior secondary panel (a thermally-broken IGU placed inboard of the historic panel) — the historic panel reads from the inside, the IGU does the energy work.
Contemporary Art Glass
Modern art glass studios (Judson Studios in LA, Bullseye Glass in Portland) produce contemporary stained-glass panels integrated into thermally-broken aluminum or steel frames. The aesthetic ranges from traditional figurative to abstract Hans Hofmann color-field work. Pricing is $200-$600 per square foot for the panel plus framing.
Where It Belongs in Modern Design
Stair landings (the wall-of-glass moment without privacy loss). Transom windows above doors (signature without dominating). Bathroom windows (privacy plus light). Skylights over a stair (Wright’s move). Contemporary stained glass works in modern interiors when it is one piece, deliberately placed; it does not work when it is everywhere.
Mill Valley Context
On Mill Valley restoration projects — particularly the 1920s-1930s craftsman bungalows in Homestead Valley and the 1880s Victorian stock around Old Mill Park — original stained glass is part of the architectural inventory. We document it in existing-conditions phase, scope restoration cost, and decide whether to keep, restore, or replicate. our Mill Valley work for how we sequence heritage-element preservation in a working remodel.
Where Designed | Curated Sits
We do heritage-glass restoration as part of broader Mill Valley remodels. The work goes to specialist studios — we coordinate and integrate, we don't fabricate. See our Mill Valley hub for the Mill Valley hub.