Richmond Hill Homes: Arched Window Replacement Without Losing the Curve

Why Richmond Hill Has So Many Arched Windows

Drive through any neighborhood south of Major Mackenzie and north of Highway 7 — the subdivisions built between 1998 and 2012 are full of arched top windows. Builders in that era loved the look. Half-rounds over front entries, quarter-circles flanking great room windows, full arches in stairwells.

Twenty years later, those windows are fogging up, the seals are failing, and the argon gas is long gone. The frames are usually still fine — vinyl with welded corners holds up well in Ontario's freeze-thaw cycles. But the glass units need replacing.

The problem: you can't order an arched IGU off a shelf.

The Template Process

Every arched window replacement starts with a physical template. Here's how we do it:

1. Cardboard trace. We press rigid cardboard against the interior stop and trace the exact curve. Freehand measurements don't work — brick openings are never perfectly symmetrical.
2. Digital verification. We photograph the template against a grid and cross-reference with a digital protractor. The radius gets confirmed to within 1mm.
3. Manufacturer submission. The template goes to the fabricator along with the glass spec (Low-E type, spacer bar width, gas fill, tint).

Why this matters: A standard rectangular window has four measurements — width, height, and two diagonals. An arched window has those plus the radius, the spring line (where the curve starts), and the arc length. Miss any one and the unit won't seat into the frame.

Pro Tip: If your arched window has grilles (muntins), we photograph the existing pattern and replicate it in the new glass. Colonial, prairie, diamond — whatever the original builder used.

What Does It Cost in 2026?

Arched window pricing in the GTA depends on three variables:

Factor	Impact on Cost
Size	A 24" × 36" half-round starts around $1,500 installed. A 48" × 72" full arch pushes $3,800.
Glass spec	Double pane with standard Low-E is baseline. Triple pane or Cardinal Loē-180 adds $200-$400 per unit.
Accessibility	Second-floor arches need scaffolding or ladder staging, adding $150-$300 to labor.

For comparison, a standard rectangular casement of similar size runs $600-$1,200 installed. The curve premium is real — custom fabrication, manual glazing, and precise fitting all add time and cost.

Frame Options for Curved Windows

Not all frame materials bend the same way:

Vinyl with aluminum reinforcement — the standard for residential arch tops in Ontario. The vinyl extrusion is heated and bent to the template radius, then reinforced internally with aluminum bar stock. This handles thermal expansion across our -25°C to +35°C range without warping.

Fiberglass — stronger than vinyl, but more expensive and fewer fabricators handle curved profiles in the GTA. Worth considering for very large arches (over 60" wide).

Wood — beautiful, but demanding. Requires regular painting or staining, and the curved sections are prone to moisture intrusion at the joints. We see a lot of rotted wood arch frames in Richmond Hill homes built before 2005.

Aluminum — commercial grade. Excellent for storefront glass and curtain wall systems, but overkill and cold-feeling for residential arch tops.

The "Just Square It Off" Temptation

We hear this from homeowners trying to save money: "Can't you just put in a rectangular window and fill in the arch with drywall?"

You can. But here's what happens:

• Curb appeal drops. The arch is a design feature. Removing it makes the front elevation look like a renovation gone wrong.
• Resale value takes a hit. Real estate agents in Richmond Hill consistently flag squared-off arches as a negative in listing notes.
• The brick opening still has the curve. You'll need a custom exterior panel to fill the gap, which often costs as much as just ordering the right window.

Our recommendation: keep the arch. The premium over rectangular is 50-100%, but you're preserving the home's architectural intent.

Glass Spec for Energy Efficiency

Since 2017, the Ontario Building Code (SB-12) requires a maximum U-value of 1.6 W/m²K for windows in Climate Zone 1 (which covers the entire GTA). For arched windows, we typically spec:

• Double pane, argon-filled, Low-E — U-value around 1.4-1.6. Meets code.
• Triple pane, argon-filled, dual Low-E — U-value around 0.9-1.2. Exceeds code and qualifies for ENERGY STAR Canada certification.

The NAFS-08 (North American Fenestration Standard) rating also applies — it governs air leakage and water penetration. Custom arch tops must pass the same tests as rectangular units.

If you're replacing multiple windows at once, check if you qualify for the Canada Greener Homes Grant or municipal rebates. Some Richmond Hill homeowners have recovered $1,000-$5,000 by upgrading to ENERGY STAR-rated units across the home.

Our Process: From Consultation to Install

Here's the timeline for a typical arched window replacement in Richmond Hill:

1. On-site consultation (Day 1) — We measure, template, photograph, and discuss glass options. Free, no obligation.
2. Quote delivery (Day 2-3) — Detailed written quote with glass spec, frame material, and install cost broken out.
3. Fabrication (Weeks 1-8) — The manufacturer builds the unit to our template. We confirm dimensions before shipping.
4. Installation (Week 9-10) — We remove the old IGU or full frame, install the new unit, insulate with low-expansion foam, and seal with high-grade caulking.
5. Cleanup and walkthrough — We haul away the old glass, vacuum the tracks, and walk you through the warranty.

Total elapsed time: 8-10 weeks. The install day itself is usually 2-3 hours per window.

When to Replace the Full Frame vs. Just the Glass

If the vinyl frame is still rigid, the corners are welded tight, and the weatherstripping seals against a card test — you probably just need a glass-only replacement. We pop out the old IGU and drop in a new one, matched to the existing curve.

Full frame replacement makes sense when:

• The frame is cracked, warped, or separating at the welds
• You're upgrading from single pane (some older Richmond Hill homes still have these)
• The existing frame material is wood that has rotted at the arch joints
• You want to change from a fixed arch to an operable one (casement bottom with fixed arch top)

Frequently Asked Questions

Can you replace just the glass in an arched window without changing the frame?

Yes, if the frame is structurally sound. We fabricate a new IGU to match the existing curved frame profile. This costs 40-60% less than full replacement.

How long does an arched window replacement take on site?

Most single arched units take 2-3 hours to install. The long wait is fabrication (6-10 weeks), not the install day itself.

Do arched windows meet ENERGY STAR Canada standards?

Yes. Custom arch tops can be built with Low-E coated, argon-filled double or triple pane IGUs that meet or exceed ENERGY STAR Zone 1 requirements for southern Ontario.

Will the new arched window match my other windows?

We match the frame color, glass tint, and grille pattern to your existing windows. The arch radius is traced on-site so the curve is identical to the original.

Are arched windows more expensive than standard rectangular ones?

Typically 50-100% more. The curved fabrication, custom templating, and manual labor add cost. A standard casement might be $800 installed; a comparable arch top runs $1,500-$2,400.

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Thinking about replacing the arched windows in your Richmond Hill home? We can come take a look, template the curves, and put together a quote with no pressure. Get in touch — we'll bring the cardboard.