Too Long; Didn't Read
- Lead came has a 100–120 year service life — most Streetsville and Port Credit originals are now due for re-leading or restoration.
- Matching the patina on century-old lead requires controlled oxidation and carbon-black rubbing, not just chemical darkener.
- Solder joints are the first failure point: cracked joints cause entire panels to sag within 2–3 years if left unrepaired.
- The City of Mississauga requires heritage approval for any window alteration on properties within the Streetsville, Old Port Credit Village, or Meadowvale Village Heritage Conservation Districts.
- Re-leading a heritage panel costs $800–$1,400 per window — significantly less than full replacement and preserves the original character.
Answer First: If you own a heritage home in Streetsville or Port Credit, your leaded glass windows are likely approaching the 100–120 year service life of their lead caming. Do not replace them with modern units. The lead can be re-soldered, re-cemented, and patina-matched to look exactly as it did in the 1920s. A full re-leading runs $800–$1,400 per window and preserves both the character and the property value that heritage designation protects. The key is matching the solder joints and the aged colour of the original came — that is where most contractors fail.
Why Mississauga Heritage Windows Are Failing Now
The math is straightforward. Lead came lasts 100–120 years under normal atmospheric conditions. Streetsville's Heritage Conservation District contains homes built between 1850 and 1930. Port Credit's waterfront cottages date to roughly the same era.
That means the original lead caming in both districts is at or past its expected lifespan in 2026.
The signs show up gradually:
- White powder on the lead surface. That is lead oxide. It means the metal is breaking down.
- Cracked solder joints. Tap a joint with your fingernail. If it moves, the bond is broken.
- Bowed panels. Stand outside and look at the window from an angle. If the leaded panel curves outward, the structure is failing.
- Rattling glass. Press a piece of glass gently. If it moves in its channel, the cement underneath has turned to dust.
None of these problems mean the window is finished. They mean it needs restoration — not replacement.
How Lead Caming Works: The Anatomy
A leaded glass window has three structural components. Understanding all three matters when you are hiring someone to repair yours.
1. The Lead Came (The Skeleton)
Came is the H-shaped or U-shaped lead channel that holds each piece of glass. The "H" came sits between two glass pieces, gripping both. The "U" came borders the panel edges.
Came profiles vary. Heritage homes in Streetsville typically have 1/4-inch round H came — a convex, half-round profile that reads as a soft line from the street. Port Credit cottages often use 3/16-inch flat H came, which gives a sharper, more geometric look common in Craftsman-era designs.
Quotable: The standard heart width (the vertical spine of the H) is 3/16 inch, and the flanges (the horizontal wings) range from 1/8 inch to 1/2 inch depending on the profile.
Getting the profile wrong is the most visible mistake in a bad restoration. Flat came on a home that originally had round came changes the entire character of the window.
2. The Cement (The Muscle)
Most people assume the lead holds the glass tight. It does not. The cement does.
Traditional glazing cement is a mixture of linseed oil, whiting (calcium carbonate), and lamp black. It gets forced under the lead flanges with a stiff brush or fid (a flat wooden tool), then hardens over 10–14 days into a rigid, waterproof bond.
When the cement fails — and after 80–100 years it always does — the glass becomes loose in its channel. Wind vibration then cracks the solder joints, and the panel begins to sag. Re-cementing alone can stabilize a panel for another 30–50 years if the lead itself is still sound.
3. The Solder Joints (The Knees)
Every point where two or more lead cames meet is joined with 60/40 tin-lead solder. A typical 24-by-36-inch heritage panel has 40–60 solder joints. Each one is a potential failure point.
Solder cracks for three reasons: thermal cycling (freeze-thaw expansion), wind vibration, and physical impact. Once a joint cracks, the rigid matrix becomes a hinge. The panel bows. More joints crack. The failure accelerates.
Quotable: A single cracked solder joint in a 50-piece leaded panel can cause measurable bowing within 2–3 years.
The Re-Leading Process: Step by Step
When the lead is too far gone to patch — oxidized, stretched, or crumbling — the panel needs full re-leading. Here is exactly what that involves.
Step 1: Removal and Documentation. We photograph and number every glass piece in the panel before touching anything. Heritage panels are puzzles. If we lose the map, we lose the pattern.
Step 2: Careful Dismantling. We heat each solder joint with a low-watt iron to soften it, then peel the old came away from the glass. Every piece of glass gets cleaned and inspected. Cracked or broken pieces are set aside for matching.
Step 3: Profile Matching. We select new lead came that matches the original profile — round or flat, and the exact width. Heritage-grade restoration lead, manufactured from commercially pure lead, is stronger than the mass-produced came from the early 1900s while maintaining the same visual profile. We stock 1/4-inch round H, 3/16-inch flat H, and 3/8-inch colonial round for GTA heritage projects.
Step 4: Re-Assembly. Glass pieces are laid back into the new came on a flat bench, working from one corner outward. Each joint is fluxed and soldered with 60/40 tin-lead. A skilled technician produces a smooth, slightly domed solder bead — not a blob, not a flat smear.
Step 5: Cementing. Glazing putty is forced under every flange with a stiff brush, then cleaned off the glass surface. The panel sits flat for 10–14 days to cure.
Step 6: Patina Matching. This is the step that separates professional restoration from amateur work.
Matching 100-Year-Old Patina
New lead is bright silver. A century-old came is deep charcoal grey to nearly black. If you re-lead a panel and skip the patina work, the new sections glow like chrome against the weathered original. It looks terrible.
The natural dark colour on old lead is lead suboxide (Pb2O). It forms slowly through decades of atmospheric exposure — oxygen, moisture, and trace sulphur compounds in the air react with the lead surface.
Our Patina Process
- Roughing. We sand the new came lightly with 400-grit abrasive cloth. This opens the grain and gives the patina something to grip.
- Carbon black application. We rub lamp black (carbon black pigment) into the roughened surface with a cotton pad. The carbon settles into the micro-scratches and darkens the lead to a convincing gunmetal grey.
- Chemical acceleration. For a deeper match, we apply a dilute patina solution (copper sulphate based) that reacts with the lead surface to produce a thin oxide layer. This must be neutralized and cleaned within minutes — left too long, it produces a white powdery deposit that ruins the finish.
- Wax seal. We finish with a thin coat of microcrystalline wax. This locks the colour and slows future oxidation, keeping the new and old sections visually consistent for years.
Quotable: Properly patinated new lead came is visually indistinguishable from century-old caming at a distance of 3 feet within 6–8 weeks of outdoor exposure.
Solder Joint Colour
Fresh solder is shiny. Old solder is matte grey. We use the same carbon-black technique on the solder beads, but with extra care — solder is a tin-lead alloy, not pure lead, so it oxidizes differently. We sometimes add a light ammonia wash before the carbon black to accelerate the initial tarnish on the tin component.
Mississauga Heritage Permit Requirements
Mississauga has three Heritage Conservation Districts (HCDs), each with its own plan governing window alterations:
- Streetsville HCD — Plan adopted December 2024. Covers roughly 200 properties along Queen Street South, Main Street, and surrounding residential blocks.
- Old Port Credit Village HCD — Plan approved January 2020. Covers the original village grid between Lakeshore Road and Lake Ontario.
- Meadowvale Village HCD — Designated 1980, updated 2014. The oldest protected district in Mississauga.
The rule: If your property is designated under any of these HCD plans, changes to windows — including replacement of glazing components — require heritage approval from the City.
The nuance: Like-for-like repair (re-soldering, re-cementing, patina restoration) is generally treated as maintenance, not alteration. You do not need a permit to re-solder a cracked joint. But if you are re-leading an entire panel with new came, or replacing broken glass with a different texture or colour, the district plan may require approval.
Our approach: We document the existing window condition with photographs and measurements, carry out the work to match the original specifications, and provide a restoration report that satisfies the heritage review if questions arise. We have handled heritage window projects across the GTA, including residential window replacement in designated districts and glass replacement on century-old sashes.
When Repair Is Not Enough: Encapsulation
Some heritage panels are too fragile for single-pane reinstallation. The glass is original, the lead is restored, but the homeowner needs insulation.
The solution is encapsulation. We seal the restored leaded panel between two panes of Low-E glass with argon gas fill, creating a triple-pane thermal unit that looks historic from the street but performs like a modern window. The R-value jumps from about 1 (single pane) to 8 (triple pane with argon). If you are weighing the thermal performance side, our piece on tinted home windows and heat management covers how glass coatings affect energy transfer.
Quotable: Encapsulating a heritage leaded panel inside a sealed thermal unit improves the window's R-value by approximately 700% while preserving the original artifact.
Encapsulation also eliminates lead dust exposure. That white powder on old came is lead oxide — toxic if inhaled or ingested. Sealing it inside a unit removes the hazard entirely.
Cost Guide: Mississauga Heritage Leaded Glass (2026)
| Service | Cost Per Window | Timeline |
|---|---|---|
| Solder joint repair (in-situ) | $150–$400 | Same day |
| Re-cementing only | $200–$500 | 2–3 weeks (cure time) |
| Full re-leading | $800–$1,400 | 4–6 weeks |
| Re-leading + encapsulation | $1,200–$2,000 | 5–7 weeks |
| Single glass piece replacement | $100–$300 | 1–2 hours |
These prices reflect panels up to 36 by 48 inches with 30–60 glass pieces. Larger or more complex panels — rose windows, curved glass, painted glass — cost more.
Sourcing Replacement Glass
Your 1920s window does not use modern float glass. It uses drawn glass — sometimes called antique glass or restoration glass. Drawn glass has subtle waves, seeds (tiny bubbles), and thickness variations that give it life and movement.
If we replace a cracked piece with modern float glass, the difference is obvious. Float glass is perfectly flat and uniform. It reads as a dead spot in the panel.
We source restoration glass from specialty manufacturers (Lamberts, Wissmach, Kokomo) who still produce glass using historical methods. Matching the texture, colour, and opacity of a specific piece can take time, but it is the difference between a repair that disappears and one that advertises itself.
Quotable: Restoration-grade drawn glass costs 4–8 times more per square foot than modern float glass, but it is the only option that visually disappears into a century-old panel.
Frequently Asked Questions
How much does leaded glass repair cost in Mississauga?
A straightforward solder-joint repair on a heritage leaded glass window runs $150–$400 per panel in Mississauga as of 2026. Full re-leading — removing all old came and replacing it with new lead matched to the original profile — costs $800–$1,400 per window depending on panel size, number of glass pieces, and whether any glass needs to be sourced from specialty suppliers. Encapsulation into a sealed thermal unit adds another $400–$600 per panel.
Do I need a heritage permit to repair leaded glass windows in Mississauga?
If your property is within the Streetsville, Old Port Credit Village, or Meadowvale Village Heritage Conservation Districts, any alteration to windows on a designated property requires heritage approval from the City of Mississauga. However, like-for-like repair — re-soldering joints and re-cementing existing lead came — is generally classified as maintenance, not alteration, and does not require a permit. Full re-leading or glass replacement may trigger the permit process depending on your district plan.
How do you match new lead came to 100-year-old patina?
New lead came is shiny silver. To match century-old caming, we first rough the surface with fine abrasive cloth to open the grain, then apply a thin coat of carbon black (lamp black) and rub it into the metal. This replicates the natural lead suboxide (Pb2O) that forms over decades of atmospheric exposure. We finish with a light wax to lock the colour and prevent premature white oxidation. The result is visually indistinguishable from the surrounding original lead within weeks.
What causes leaded glass panels to sag or bow?
Two things: failed solder joints and degraded cement. Every intersection of lead came is soldered with 60/40 tin-lead alloy. Vibration from traffic, wind, and thermal cycling cracks these joints over decades. Once a joint breaks, the rigid matrix becomes a hinge and the panel bows outward. Simultaneously, the linseed-oil putty (cement) under the lead flanges dries out and turns to powder, releasing the glass pieces from their channels. Both problems compound each other — a sagging panel flexes more, cracking more joints, accelerating the collapse.
Can you replace just one broken piece of glass in a leaded window?
Yes. We cut the lead came flanges around the broken piece, fold them back, remove the shards, fit a new piece of glass matched to the original texture (drawn glass, cathedral glass, or seedy glass — not modern float glass), fold the flanges back down, and re-solder the joints. This is called an in-situ repair. It takes 1–2 hours per piece and avoids removing the entire panel from the frame.
How long does a full re-leading job take?
Allow 4–6 weeks from removal to reinstallation. The panel must be carefully dismantled, each glass piece cleaned and catalogued, new lead came cut and fitted, all joints soldered, and cement applied under every flange. The cement then needs 10–14 days to cure before the panel can be handled and installed. We provide temporary glazing or plexiglass boarding for the opening while the work is in progress.
Protect What Makes Your Home Worth Protecting
Heritage designation in Streetsville and Port Credit exists because these neighbourhoods have something worth keeping. The leaded glass in your windows is part of that character — handmade, imperfect, and irreplaceable by modern manufacturing.
If your lead is cracking, your joints are failing, or your panels are bowing, the fix is restoration, not replacement. We handle heritage leaded glass projects across Mississauga — from single solder repairs to full re-leading with patina matching. Reach out for a free assessment and we will tell you exactly what your windows need.