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Circle & Arched Windows
The shapes that give a house its character, where they belong, and how to get them right the first time.
Why Specialty Shapes
Rectangles do the work. Curves do the talking.
Drive through Scarsdale, Chappaqua, or Greenwich and look at the houses you remember. Nine times out of ten the detail that stuck is a window that is not a rectangle: a half-round over the door, a round window in the gable, an arch-top on the stair. Specialty windows are a small share of any project and a large share of what people notice.
They are also where window projects most often go wrong. A half-round with the wrong radius, an arch whose grilles do not match the sashes below it, a round window set too high in a gable: these are mistakes you live with for thirty years. We have installed and replaced hundreds of specialty windows across Westchester, Putnam, and Fairfield County, and this guide covers what we have learned about getting them right.
Everything below applies whether you are adding a specialty window to a new addition, replacing one that has failed, or deciding whether your facade needs one at all.
Who Wrote This
Sunrise Carpentry
Andersen Premier Partner, Yorktown Heights, NY. Windows and carpentry since 1994.
Specialty windows are a carpentry problem as much as a window problem. The curved trim, the header, the flashing on a round opening: that is the part we have been doing for 30 years.
The Shapes
Eight shapes, and where each one belongs
01
Full Circle (Round)
Gable peaks, over a tub, beside a front door, stair landings
The purest accent. Works at any size from a 20-inch porthole to a 5-foot feature. Spoke or sunburst grilles echo colonial and Victorian trim.
02
Half-Round (Springline)
Above a picture window, over an entry door, in a dormer
The classic Westchester shape. Its radius should equal half the width of the window or door below so the trim lines run continuously.
03
Quarter-Round
In pairs flanking a chimney or a center window, in low gables
Two quarter-rounds back to back read as a half-round split by a mullion. Useful where a structural post or beam sits in the middle.
04
Elliptical
Above wide entries and double doors, in shallow gables
Wider and lower than a half-round. Fits where there is not enough head height for a true semicircle.
05
Eyebrow
Low rooflines, shingle-style and cottage homes, dormers
A long, shallow curve that looks like it grew out of the roof. Almost always fixed, often custom-built.
06
Arch-Top (Round-Top)
Tall living room windows, stair towers, Mediterranean and Tudor homes
A rectangular window with a curved head. The arch can be a full semicircle or a gentle segment. Available as a fixed unit or an operating casement.
07
Gothic & Pointed Arch
Tudor revival, church-inspired great rooms, period restorations
Two arcs meeting at a point. A statement piece for the right house, out of place on the wrong one.
08
Octagon & Hexagon
Bathrooms, hallways, attic gables, mudrooms
A small geometric window gives the same accent as a circle with simpler trim. Available fixed or venting.
Ideas
Six places a circle or arch earns its keep
Over the front door
A half-round or elliptical transom above the entry is the single highest-impact specialty window on most homes. It brightens the foyer, raises the apparent height of the door, and reads clearly from the street. Match its radius to the door-plus-sidelight width.
Crowning a picture window
Set a half-round on top of a large fixed window, or on top of a trio of double-hungs, and the whole assembly becomes one composite unit. Andersen builds these as a single factory-mulled piece so the sightlines and finish match exactly.
In the gable
A round or octagon window high in a gable lights an attic, a vaulted bedroom, or a stair tower, and it finishes the facade the way a period home expects. On a cape or colonial, a single round window in the front gable is often all the ornament the house needs.
Above the tub
A small round or oval window above a bathtub brings daylight to the one wall that usually has none, keeps privacy with obscure glass, and gives the room a focal point. Specify tempered glass; near a tub it is required.
On the stair landing
A tall arch-top on a landing lights two floors and gives the stair a destination. Because nobody needs to open it, it can be as large as the wall allows, which is where the Andersen A-Series and E-Series come in.
Inside the house
Specialty shapes work as interior windows too: a round window between a hallway and a sunroom, a half-round over a pair of French doors, a glazed transom above a bedroom door in a historic house.
Getting It Right
Six rules we follow on every specialty window
None of these are complicated. All of them get skipped by installers who sell windows but do not do trim carpentry.
01
Line up the radii
The arch's center point should sit on the line of the head trim below it, and its radius should equal half the width of the opening. When these two things are true the casing flows continuously. When they are not, the window looks stuck on.
02
Pick one grille language
Spoke, sunburst, hub-and-spoke, or none. Match the grille bar width and the lite proportions to the rectangular windows beside it. Andersen offers the same grille profiles across its specialty and standard units for this reason.
03
Respect the house
Colonials want half-rounds and the occasional gable circle. Tudors want pointed or segmental arches. Shingle-style homes want eyebrows. Contemporaries usually want none, or one enormous fixed round.
04
Plan the interior trim
Curved casing is the hardest trim in the house to do well. Flexible moldings, kerfed wood, or a plain drywall return are all options. Decide before the window is ordered, because jamb depth depends on it.
05
Decide fixed or venting early
Most specialty windows are fixed. Round venting units and arch-top casements exist and cost more. If airflow matters in that room, put an operating window below the arch instead.
06
Think about cleaning
A round window in a two-story gable gets cleaned from a ladder or not at all. Low-maintenance Fibrex or clad exteriors and high-quality Low-E glass keep it looking right between washings.
Specialty Windows We've Installed
Windows Gallery →
The Practical Part
What to expect when you order one
Specialty windows are made to order. That affects timing, price, and how early in a project they need to be decided.
Andersen availability
Circles and ovals come from the 100 Series and A-Series. Arches, half-rounds, and ellipticals come from every series, and the 400 Series Springline arch-top opens. The E-Series builds oversized and custom-sized shapes to order.
Lead time
Six to ten weeks is typical. We measure specialty openings first and order them before the standard windows so everything installs in one visit.
Cost
Higher per square foot than a rectangle, because the frame is curved and the unit is custom. On a whole-house project the one or two specialty units are a small share of the total.
Structure and permits
A new opening needs a header and usually a permit. Replacing a specialty window in its existing opening usually does not. We handle both.
Common Questions
Frequently Asked Questions
Can arched or round windows open?
Some can. Andersen's 400 Series Springline is an arch-top single-hung that opens, and any arch or half-round can sit above an operating window as part of one assembly. Most specialty windows are fixed because the shape makes a weather-tight operable sash expensive. Our usual advice is to keep the specialty unit fixed and put the ventilation in the rectangular window beside or below it.
Which Andersen series offers circle and arched windows?
All of them, with different shape lists. The 100 Series and A-Series offer circles, ovals, arches, half-rounds, and ellipticals. The 400 Series offers arches, half-rounds, ellipticals, unequal-leg arches, and the operable Springline arch-top. The E-Series builds arches, half-rounds, and ellipticals to order in oversized and custom sizes. We match the series to the rest of the windows on the house so the profiles and colors line up.
How long do specialty windows take to arrive?
Longer than standard rectangles. Expect six to ten weeks for most custom shapes, sometimes more for E-Series or unusual sizes. We measure early and order specialty units first so the whole project installs together.
Do specialty windows cost a lot more?
Per square foot of glass, yes. A half-round or circle typically costs several times what a plain rectangle of similar size costs, because it is made to order and the frame is curved. Because they are usually small and used once or twice on a house, the effect on the total project is modest, and the effect on the facade is not.
Can you replace an existing arched window with the same shape?
Yes. We template the existing opening, confirm the radius and spring line, and order a matching unit. This is common on 1980s and 1990s Westchester colonials, where the original half-rounds have failed seals or rotted frames. Replacing the arch and the rectangular windows beneath it as one factory-mulled unit usually gives the cleanest result.
Do I need a permit to add a round window in a gable?
Adding a new opening is structural work, so most towns in Westchester, Putnam, and Fairfield County require a permit even for a small window. Replacing an existing specialty window in the same opening usually does not. Historic districts are the exception either way. We confirm and handle the filing.
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Specialty and standard Andersen windows, installed by an Andersen Premier Partner with the trim carpentry to match. Serving Westchester, Putnam, and Fairfield County since 1994.
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