Arch tops
An arch spans an opening with a curve instead of a flat beam, and the curve names it: round, segmental, elliptical, Gothic or Tudor. A new arch-top window has to match whichever one the wall already has.
Custom Shaped Windows in Austin, Built to the Opening
Austin Quality Windows templates and installs custom shaped windows in Austin, TX, and is Travis County's leading specialist in openings that are not rectangles, specializing in arch-top windows over doors and picture units, round and oculus windows, and trapezoid windows that follow a roofline. We offer gable-end window groupings and high clerestory runs.
- Free in-home measure
- Elevations you approve
- Installed to manufacturer instructions
- One written price
About our custom & architectural shape windows
Our team provides a full-size template of every curved or angled opening, delivering a sash that follows the masonry line exactly for both residential and commercial projects. Our own crew measures the spring line, radius or rake angle of each opening, sends drawings of every shape for your approval before anything is built, and installs and flashes the finished unit.
From finding the true spring line of an old brick arch to glazing an entire gable wall, our team handles every detail. Serving Austin, Lakeway, The Hills and Volente, we fit shaped glass to homes where the roof and the walls rarely meet at a right angle.
Why Austin Quality Windows
How We Work
No handoffs between a salesperson, a measurer and a subcontracted crew. The crew that measures your openings installs the windows.
Measured on siteEvery opening measured in the wall it sits in, by the crew that will install it
Elevations firstYou approve the drawings, sizes, glass and finish before anything is ordered
Flashed to specSill pans, flashing and sealant to the manufacturer's written instructions
Water testedOpenings checked for leaks before the interior trim goes back on
The Shapes We Build and Where They Go
A shaped window is almost always the one the room is designed around, so each type answers a different part of the house.
Arches come in several curves. A semicircular or round arch is a half circle, the most common form in Roman and Renaissance building. A segmental arch is a shallower slice of a circle, and an elliptical arch is flatter still. A pointed or Gothic arch meets at a peak, and a Tudor arch is a four-centred curve flattened almost straight at the top.
Transoms and fanlights
A transom is the window above a door. When it is fan-shaped, it is a fanlight, and it is where many arch-top units in a house begin. A large semicircle divided into three sections is called a thermal or Diocletian window.
Rounds
A round opening in a wall is an oculus, from the Latin for eye. Set high in a gable or at the end of a hall, it reads as a feature from the street and a spot of light from inside.
Trapezoids and triangles
A rake window follows a sloped roofline, so every edge is straight: a right triangle or a trapezoid. They stack above a run of rectangles to fill the triangular part of a wall.
Clerestories
A clerestory is a high band of windows above eye level. It brings light and air into the middle of a room while keeping the view out of it, which is why it suits a street-facing wall or a close neighbor.
Templating the Opening, Not the Old Glass
The single most important step on a shaped window happens before it is ordered. We measure the opening as it is today, never the old glass, because a house that has settled over the years no longer matches the drawing its first window was cut for.
On a rake opening, the angle is calculated from the height difference over the base and cross-checked against the length of the sloped side. Precision matters: on a 36-inch base, a one-degree error opens a gap of about five eighths of an inch at the peak. On an arch, the spring line is the level where the curve starts to rise from its supports, and a traced template makes the curve of the sash follow the curve of the brick or stone. In masonry, the wedge-shaped blocks of the arch are voussoirs, the top one is the keystone, and the underside is the intrados, the surface your new frame sits against.
Rake and trapezoid openings
A rake unit needs four numbers: the base width jamb to jamb, the tall-side height, the short-side height and the rake angle. We also mark a reference corner, so the unit is not built as a mirror image.
Arched and round openings
An arch is recorded as a radius and a spring line, with the span across the opening and the rise to the crown. Where the masonry is irregular, a full-size template traced from the opening goes to the builder.
Masonry openings
In a masonry wall the arch itself carries the load, working as a curved lintel. We leave that structure alone and build the window to it, rather than cutting the wall to suit a stock shape.
Gable Walls, Clerestories and the Glass They Need
A gable is the triangular section of wall between two roof pitches, and its angle is set by the pitch of the roof. That makes a gable wall the natural place for a group of shaped units: rectangles below, trapezoids or triangles above, all following the rafters.
Glass for these openings answers to code. Travis County is in Climate Zone 2, where the 2015 IECC caps solar heat gain at 0.25 SHGC and window U-factor at 0.40, and the SHGC limit applies to every window, skylight and glazed door, including replacement work. A low-E coating reflects infrared and keeps heat on the outside while letting daylight in. A pane larger than 9 square feet that runs within 18 inches of the floor and above 36 inches is a hazardous location under the model residential code, and a tall arched unit set low in a stair or entry can meet that test, so it gets safety glass. We specify units carrying an NFRC label, so the SHGC and U-factor on paper are the ones the inspector reads.
Fixed or operable
Most arch tops, rounds and rake units are fixed, since opening a triangle gains little and costs weather sealing. Where you want air, the shaped unit sits over an operable casement, awning or hopper of the same frame.
Glass for high and west-facing openings
A gable often faces the afternoon sun and a clerestory catches light most of the day, so these units get low-E glass held to the Climate Zone 2 limits, and safety glass wherever a low, tall pane calls for it.
Installing a Shaped Unit So It Stays Dry
A curved or sloped head is harder to keep dry than a flat one, because water runs along it rather than straight off. So the flashing has to be right.
The installation standard for windows, ASTM E2112, laps every flashing layer like shingles, each over the one below, so water always runs down and out. The sill pan goes in first and slopes to the outside to drain anything that gets past the frame. Around an arch the head flashing follows the curve. The standard defers to the manufacturer's installation instructions, and we follow them on every shaped unit.
Before the interior trim goes back, we water-test the installed unit, then set the casing. On an arch that casing is often curved as well, and it is measured from the same template as the window.
What Drives the Cost of Custom Shaped Windows
We do not publish a price for shaped units, because every one is drawn for a single opening. What moves the figure:
- The shape itself. A trapezoid built from straight edges is simpler than a true radius, and an elliptical or Gothic arch more involved again.
- The glass package. Dual or triple pane, the low-E coating and its solar heat gain, laminated glass for sound, tempered or laminated glass where the code requires safety glazing, tint and gas fill.
- Frame material. Vinyl, fiberglass, aluminum-clad wood or thermally broken metal, and the interior wood species and finish.
- Size and count. One fanlight over a door against a full gable wall of stacked units, and fixed against operable sections.
- Grilles. Radial or divided lites that follow the curve.
- Structural work. Enlarging a gable opening or adding a clerestory means new framing and a header, and a wide or tall opening may need an engineer's letter.
- Access. A gable peak or clerestory is high by definition, so a lift and staging are often part of the job, more so on a sloped Hill Country lot.
- Historic and HOA review. A City of Austin historic property or a POA committee that wants the drawings first.
- Trim and wall repair. Curved interior casing, and stucco, stone or siding patched around the new frame.
The free in-home measure is where the price comes from: we template the opening, talk through the glass and frame, and give you the figure and scope in writing.
Permits and Approvals for Shaped Openings
Filling an existing opening with a new shaped unit is one kind of job. Cutting a new one, or making an old one bigger, is another, and the rules change with it. We check the current rule for your address at quote time.
- Lakeway. Any framing change to make an opening bigger is permitted work under the city's 2021 IRC and IECC, and the fee doubles if work starts before the permit is issued.
- The Hills. The POA, not the village, approves window and glass changes through an architectural modification request, and crews and glass trucks come in through the guard gate on private roads.
- Volente. The village enforces the 2018 IRC and IECC, remodel permits are filed with the village by email, and fees are paid by check only.
- City of Austin historic properties. The Historic Design Standards say not to enlarge, move or enclose historic window openings that are highly visible from a front or side street, and to match the size and details of the existing window when one must be replaced.
We draw the elevations and the shape details a reviewer needs and work through the submission with you, so the approval and the order line up.
The process
From First Measure to Finished Openings
Four steps, and nothing is ordered until you have signed off on the drawings and the price.
Free in-home measure
We measure every opening, check the framing and the header, and talk through glass, frame material and how each window should operate.
Elevations and a written price
You get drawings of every unit for your approval and for any HOA or historic review, with one written price.
Ordered to your sizes
Units are ordered to the approved sizes and glass package, and checked against the drawings when they arrive.
Installed and water tested
Old units out, openings flashed, new units set, sealed and water tested, then trim and cleanup.
More of What We Install
Service area
Where We Install
- window installation in Rollingwood
- Barton Creek windows and glass doors
- window installation in West Lake Hills
- Tarrytown windows and glass doors
- window installation in Lost Creek
- window installation in Volente
- Sunset Valley windows and glass doors
- window installation in The Hills
- window installation in Lakeway
- Steiner Ranch
Questions
Custom & Architectural Shape Windows: Common Questions
What drives the price of a custom shaped window?
The shape, the glass package, the frame material, the size and number of units, grilles that follow a curve, any new framing or header, access to a high opening, and any historic or POA review. We give you a written figure after the free measure.
How long from order to install?
Shaped units are built one at a time to the template, so it depends on the manufacturer and the glass. We give you the date in writing with the quote.
Can you match an existing brick or stone arch?
Yes. We record the spring line, span, rise and radius, and trace a full-size template where the masonry is irregular, so the new frame follows the arch rather than the wall being cut to fit the frame.
Can a shaped window open?
Most arch tops, rounds and rake units are fixed. Where you want ventilation, we pair the shaped unit with an operable casement, awning or hopper below it in the same frame.
Do I need a permit or HOA approval?
Often. A bigger opening means new framing, which Lakeway and other cities permit, and POA committees such as The Hills review window changes. We prepare the drawings and help file them.
What glass works in a west-facing gable?
A low-E coating with a low solar heat gain coefficient inside an insulated unit, and safety glass where a large pane sits low. The NFRC label on each unit shows its SHGC.
What happens at the measure?
We measure and template every shaped opening ourselves, look at the framing or masonry around it, and follow up with drawings and a written quote.
Is there a warranty?
Yes, a written warranty comes with every installation, and we explain it with the quote.
Free in-home measure
Talk to us about custom & architectural shape windows
Free in-home measure across Austin and the west side. We call you back to set a time.
Calls only, we do not receive text messages.