Markham Windows: Grid Patterns — Prairie vs. Colonial and How to Match Your Home's Architecture
Too Long; Didn't Read
- Prairie grids frame only the corners of the window — a perimeter border with an open centre. Colonial grids divide the window into a full checkerboard of equal rectangles.
- Prairie style suits Craftsman, mid-century, and contemporary homes common in Markham's newer Unionville and Cornell developments. Colonial suits Georgian, Cape Cod, and traditional two-storey homes found in older Markham Village.
- Grid types: SDL (Simulated Divided Lite) has bars bonded to both sides of the glass with a spacer bar between panes. GBG (Grilles Between Glass) sits inside the sealed unit. Snap-in grilles clip to the interior only.
- SDL provides the most authentic look and adds the most resale value. GBG is the easiest to clean (flat glass surface). Snap-in grilles are the cheapest but look like what they are.
- Adding or changing grids does not require full window replacement — you can order new SDL bars or GBG inserts for existing frames from most major manufacturers (Gentek, North Star, JELD-WEN).
Answer First: Prairie grids frame the corners. Colonial grids divide the whole pane. That is the fundamental difference, and picking the wrong one for your Markham home's architecture is like putting a spoiler on a minivan — technically possible, structurally fine, visually wrong. Prairie suits Craftsman, contemporary, and mid-century homes. Colonial suits Georgian, Cape Cod, and traditional builds. Match the grid to the house, not to your neighbour's preference.
The Grid Question Nobody Asks Until It Is Too Late
You are replacing your windows. The sales rep asks: "Do you want grids?" You have 30 seconds to decide on something you will look at for the next 25 years. Most homeowners default to "whatever was there before" or "no grids, they're old-fashioned."
Both answers can be wrong.
Grids are an architectural element. They tie windows to the design language of the house. The right grid pattern makes a home look intentional. The wrong one — or the absence of one on a house that needs it — makes the windows look like they were bought at a clearance sale.
In Markham, this matters more than most places. The city spans everything from 1850s Ontario Cottage homes in Markham Village to 2020s contemporary builds in Cornell and Berczy. The grid that works on one will look absurd on the other.
Prairie Grids: The Clean Frame
The Pattern
Prairie grids place bars along the perimeter of the glass, typically 3–4 inches from the edge. The centre of the window is one large, unobstructed pane. Some variations add a single horizontal or vertical bar bisecting the centre, but the hallmark of prairie style is the open middle.
The Architecture It Matches
- Craftsman bungalows — The prairie grid was literally designed for this style. Frank Lloyd Wright's Prairie School used this grid to emphasize horizontal lines and connection to the landscape
- Mid-century modern — The clean lines and minimal divisions suit the simplicity of mid-century design
- Contemporary custom homes — Newer builds in Markham's Angus Glen, Cornell, and Cathedraltown developments often use prairie grids to add detail without sacrificing the view
- Transitional styles — Homes that blend traditional proportions with modern finishes
Where You See It in Markham
The newer subdivisions north of 16th Avenue — Unionville, Cornell, Berczy Glen — have a high concentration of homes suited to prairie grids. These developments mix Craftsman and transitional architectural styles that benefit from the grid's clean perimeter framing.
Colonial Grids: The Traditional Checkerboard
The Pattern
Colonial grids divide the window into a uniform matrix of rectangular panes — 2 across by 2 down (2x2), 2 across by 3 down (2x3), or 3 across by 3 down (3x3). Every section is the same size. The look evokes the original multi-pane windows that existed before large sheets of glass were economically viable.
The Architecture It Matches
- Georgian and Federal — Symmetrical facades with 6-over-6 or 8-over-8 double-hung windows. Colonial grids are non-negotiable on these styles
- Cape Cod — Small-paned windows with 4-over-4 or 6-over-6 grids
- Victorian — Upper sashes often had decorative grids while lower sashes were clear. A "top-only" grid is period-correct for many Victorian homes
- Heritage homes — Any home designated or listed under the Ontario Heritage Act should maintain its original grid pattern on street-facing elevations
Where You See It in Markham
Markham Village along Main Street Markham has the highest concentration of heritage and traditional homes requiring colonial grids. The Buttonville area and older sections of Unionville (around Main Street Unionville) also feature traditional architecture where colonial grids are appropriate.
Grid Construction Types
SDL — Simulated Divided Lite
Bars are permanently bonded to both the interior and exterior surfaces of the sealed glass unit. A spacer bar sits between the panes, aligned with the exterior bars, creating the illusion of true individual panes when viewed from any angle.
- Look: Most authentic. Shadow lines visible from the street
- Cleaning: Must clean around the bars on both sides
- Cost: $150–$350 premium per window over plain glass
- Best for: Heritage homes, street-facing windows, homes where curb appeal matters
SDL is the only grid type that looks correct on a traditional Markham Village home. From 10 feet away, SDL is indistinguishable from true divided lite. GBG and snap-in grids are visibly flat and fake at the same distance.
GBG — Grilles Between Glass
A flat aluminum or vinyl grid sits inside the sealed unit, between the two panes of glass. The exterior and interior glass surfaces are completely flat.
- Look: Visible but flat. No shadow lines. Looks like what it is — a grid sandwiched inside the glass
- Cleaning: Easiest. Flat glass on both sides, no bars to clean around
- Cost: $50–$150 premium per window
- Best for: Kitchens and bathrooms (easy cleaning), contemporary homes where a subtle grid is desired
Snap-In Grilles
Removable plastic or vinyl bars that clip into the interior side of the window sash. The exterior is plain glass.
- Look: Interior only. No exterior grid visible. Up close, the clips and joints are obvious
- Cleaning: Remove grilles, clean glass, snap them back. Or just leave them off
- Cost: $20–$60 per window
- Best for: Rental properties, temporary styling, budget renovations where grids are needed for architectural consistency but cost is the primary driver
Choosing the Right Grid for Your Markham Home
| Home Style | Recommended Grid | Grid Type | Typical Pattern |
|---|---|---|---|
| Heritage (pre-1920) | Colonial | SDL | 6-over-6 or 4-over-4 |
| Georgian / Cape Cod | Colonial | SDL or GBG | 3x2 or 3x3 |
| Victorian | Top-sash only Colonial | SDL | 2x2 or 3x2 upper, clear lower |
| Craftsman | Prairie | SDL or GBG | Perimeter only |
| Mid-century | Prairie or none | GBG | Minimal perimeter |
| Contemporary | Prairie or none | GBG or SDL | Perimeter if any |
| Transitional | Prairie | SDL or GBG | Perimeter with single cross |
Can You Change or Add Grids Without Replacing Windows?
Yes, in most cases:
- Adding GBG: Requires replacing the sealed glass unit (IGU) with a new unit that has the grid inside. This is a glass-only replacement — the frame stays. Cost: $200–$400 per window
- Adding snap-in grilles: Order from the window manufacturer using your frame's model number. Clip them in yourself. Cost: $20–$60 per window
- Adding SDL: Requires a new IGU with SDL bars bonded to the surfaces plus a spacer bar between panes. Cost: $250–$450 per window for the glass swap
- Removing grids: If you have GBG, the grid is inside the sealed unit — you need a new IGU without the grid. If you have snap-in, just unclip them. If you have SDL, you need a new IGU
For homes in Heritage Markham designated areas, check with the municipality before removing grids from street-facing windows. Heritage guidelines may require maintaining the original pattern.
If you are doing a full window replacement anyway, specifying the grid at order time adds only $50–$350 per window compared to ordering the same window plain. It is the cheapest time to get grids right.
Frequently Asked Questions
What is the difference between prairie and colonial window grids?
Colonial grids divide the window into a uniform grid of equal rectangles — typically 2x2, 3x2, or 3x3. Every pane looks the same size. Prairie grids frame only the perimeter of the window — horizontal and vertical bars run near the edges, leaving the centre as one large unobstructed pane. Prairie emphasizes the view. Colonial emphasizes symmetry.
Which grid pattern is best for resale value in Markham?
The grid pattern that matches your home's architectural style adds the most value. Colonial grids on a Georgian-style home or prairie grids on a Craftsman increase curb appeal. The wrong grid — colonial on a modern home, or no grids on a traditional one — can look off. SDL (Simulated Divided Lite) grids add more perceived value than GBG or snap-in because they create visible depth and shadow lines from the street.
Can I add grids to my existing windows without replacing them?
In many cases, yes. If your windows are from a major manufacturer like Gentek, North Star, JELD-WEN, or Sunrise, you can order GBG (Grilles Between Glass) inserts or snap-in interior grilles designed for your specific frame model. SDL requires replacing the sealed glass unit itself, since the bars are bonded to the glass surfaces. A glass-only swap with new SDL bars typically costs $200–$450 per window.
Do window grids affect energy efficiency?
GBG and snap-in grids have zero impact on energy performance — the sealed unit is unchanged. SDL grids add a small amount of thermal bridging where the exterior bars contact the glass, but the effect is negligible in a modern Low-E argon-filled unit. The energy rating difference between a gridded and non-gridded window of the same model is typically less than 1%.
What grid pattern was used on homes in Markham Village?
Markham Village's older homes (1850s–1920s) predominantly used true divided lite windows with colonial-style grids — 6-over-6 or 4-over-4 patterns on double-hung windows. When replacing these windows, the most historically accurate option is SDL with matching muntin bar profiles. Some Heritage Markham guidelines recommend maintaining the original grid pattern on street-facing windows.
Replacing windows and not sure about grids? Bring us a photo of your home's exterior and we will recommend the grid pattern and construction type that matches your architecture. Book a window consultation — we will get the details right so you do not have to live with the wrong grid for 25 years.