Leaded Glass Windows Fort Collins: Condensation, Drafts, and Fixes
Leaded glass windows are one of the defining features of Fort Collins’s older homes — the kind of architectural detail that draws people to Old Town’s historic streetscapes and the graceful Craftsman bungalows that line the Eastside and Westside historic districts. But as beautiful as these windows are, they come with challenges that modern double- and triple-pane units were designed to eliminate: condensation that fogs the glass surface and drafts that sneak through aging lead joints. At Fort Collins Stained Glass, we work with homeowners throughout the area to address exactly these problems — preserving original windows while making them far more comfortable for everyday living.
Why Leaded Glass Windows Collect Condensation
Traditional leaded glass windows are single-pane by nature. The individual glass pieces — held in place by H-shaped channels of lead called came — offer little thermal resistance compared to today’s sealed, gas-filled multi-pane units. In Colorado’s climate, that gap becomes very apparent very quickly.
Fort Collins winters are genuinely cold. January lows regularly fall into the upper teens, and below-zero nights are not unusual through December and February. Inside a heated home, warm air carries moisture — and when that humid indoor air contacts a cold, single-pane leaded glass surface, the moisture condenses into water droplets. You might notice fogging along the lower panes, small drips tracing the lead lines, or a persistent dampness that appears whenever temperatures drop sharply outside.
Over time, chronic condensation is more than a nuisance. Water that collects along the came can infiltrate the glazing compound — the putty-like material that bonds each piece of glass to its lead channel. As the compound softens and erodes, it loses its seal. Left unaddressed, moisture works deeper into the lead structure, accelerating corrosion and eventually compromising the panel’s integrity.
Where Drafts Enter Through Old Leaded Windows
Drafts are the other complaint we hear often from owners of historic leaded glass. Unlike a visibly broken seal, the sources of infiltration in old leaded windows aren’t always easy to spot. Several factors contribute to air leakage in panels that have been in place for decades.
The glazing compound that seals glass to came has a finite lifespan — typically several decades under good conditions. In windows from the early 1900s, common in Fort Collins’s oldest neighborhoods, that compound may be a century old or more. As it dries out and cracks, small gaps form along every glass-to-lead junction throughout the entire panel. Lead came joints at intersections and panel perimeters also loosen over time, especially after years of thermal expansion and contraction driven by Colorado’s dramatic daily temperature swings — shifts of 30 to 40 degrees within a single day are common along the Front Range. The perimeter seal between the window panel and its surrounding frame is another frequent entry point for cold air, particularly in older wood frames that have shifted with seasonal moisture changes.
The result is a window that looks entirely intact from across the room but lets in a noticeable cold draft on a winter evening — and sends your heating bill in the wrong direction.
How We Restore Leaded Glass Windows
At Fort Collins Stained Glass, replacing historic leaded windows is almost never what we recommend. These panels are original pieces of craftsmanship — in many cases made by hand more than a century ago — and they are genuinely irreplaceable. Our approach is always to restore and preserve wherever possible.
For condensation and draft issues specifically, the most common interventions we perform fall into three categories. Each is chosen based on the actual condition of the window, not a one-size-fits-all prescription.
Re-cementing is often the right starting point when the came itself is still sound but the glazing compound has dried out or cracked. We clean the old, degraded compound from every lead-glass junction in the panel and pack fresh, properly mixed cement throughout. This re-seals the window, significantly reduces air infiltration, and helps shed moisture rather than absorbing it. Many windows with moderate draft issues respond very well to this treatment alone.
Re-leading becomes necessary when the came has grown brittle, bowed, or structurally weakened — a natural result of age, especially in panels that have experienced repeated freeze-thaw cycles. We carefully disassemble the window, preserve every piece of original glass, and rebuild the panel using new lead came. The result is a window that looks identical to the original but has the structural integrity of a freshly made piece.
Protective storm glazing is one of the most effective tools for addressing both condensation and drafts without altering the historic leaded glass itself. We fit a custom secondary glazing panel — clear glass or acrylic — on the interior or exterior of the existing window frame, creating a still-air buffer zone between the leaded glass and the living space. This buffer dramatically reduces the temperature differential at the window surface, minimizing condensation while also cutting drafts. It is the approach recommended by the Stained Glass Association of America for preserving historic windows in challenging climates.
Finding the Right Fix for Your Windows
Not every leaded glass window needs the same treatment. A panel with minor compound shrinkage and no structural issues might need only re-cementing. One with bowing lead, cracked joints, and persistent cold drafts might call for a full re-lead. A window in a well-preserved panel but a drafty old frame could benefit most from protective storm glazing. That’s why we start every project with a thorough on-site assessment — examining the came condition, the glass, the compound, and the surrounding frame before recommending anything.
Fort Collins has an especially rich inventory of historic homes with original leaded glass. The Victorian-era houses near Old Town, the Arts and Crafts bungalows in the Eastside and Westside historic districts, and the older residential streets in neighborhoods like Sheely Drive all present distinct window preservation challenges. We have worked throughout these communities and understand the specific conditions — Colorado’s altitude, intense UV exposure at over 5,000 feet, and the Front Range’s dramatic thermal cycling — that put particular stress on leaded glass here.
Ready to Address Your Leaded Glass Windows in Fort Collins?
If your leaded glass windows are showing signs of condensation, drafts, or aging lead came, Fort Collins Stained Glass is here to help. We’ll assess the condition of your windows, walk you through your options clearly, and carry out the restoration with full respect for the original craftsmanship. Contact us today to schedule a consultation — and let’s make sure those windows serve your home for another century.
