Custom skylights fall into two very different buckets, and the price gap between them runs into the thousands. A custom size skylight is a standard product (most often a curb mounted VELUX FCM) built to a non catalog opening. A custom shape or bespoke skylight is a made to order glazing unit (circles, pyramids, polygons, walkable glass) from a specialty manufacturer. Knowing which one you actually need is what keeps a $2,500 job from turning into a $15,000 one.
What “custom skylights” actually means (two different products)
The phrase “custom skylights” gets used for two products that share almost nothing on price or lead time. One is a stock skylight resized to your opening. The other is a bespoke glass assembly engineered for your roof. Most homeowners who search for custom skylights need the first and get quoted the second.
| Type | What it is | Who makes it | Typical use |
|---|---|---|---|
| Custom size | A standard skylight (usually curb mounted) built to a non catalog width and length | VELUX (FCM custom), Sun-Tek, Wasco | An opening that does not match a stock size code, or a slightly larger daylight area |
| Custom shape | A made to order unit in a non rectangular shape: circle, octagon, triangle, trapezoid, pyramid, ridge | Marco, Glazing Vision, CrystaLite, Supreme, Sun Valley | Architectural rooflines, atriums, dramatic daylighting |
| Structural glazing | Walkable, drive over, or large span glass engineered as part of the structure | Glazing Vision and other architectural glazing firms | Roof decks, floor lights, spans past 10 feet |
How much do custom skylights cost?
A custom size curb mounted unit often runs about $150 to $300 per square foot for the skylight itself, roughly double the $60 to $100 per square foot of a standard double glazed unit. A small 2 by 2 foot custom shape (a pyramid over an existing curb, for example) usually lands around $2,500 to $3,000 installed. Bespoke structural or walkable glass reaches five figures and is always quoted per project.
Two factors drive the premium: size and shape. Adding a foot in each direction adds glazing area and often forces thicker glass or extra mullions to span it. Shape complexity stacks on top: a square or rectangle is cheapest, a right angle triangle costs more, and complex triangles, trapezoids, and curves cost the most.
| Route | Example | Typical price | Quote basis |
|---|---|---|---|
| Standard size (reference) | Stock VELUX FCM or FS | $60 to $100 / sq ft (unit) | Off the shelf |
| Custom size, curb mounted | VELUX FCM custom | $150 to $300 / sq ft (unit) | Size quote |
| Custom shape, small | 2×2 pyramid over a curb | $2,500 to $3,000 installed | Per project |
| Structural / walkable / large span | Floor light, roof deck glass | Five figures | Per project only |
Prices vary by region, glass package, and how much curb and flashing work your roof needs. For standard unit pricing to anchor against, see our skylight installation cost breakdown and the full skylight cost guide before you request a custom quote.
Does VELUX make custom size skylights?
Yes. VELUX builds custom size skylights through its FCM (Fixed Curb Mounted) model, which is the most versatile unit in the line for non standard openings. Custom sizes run from a minimum of 17.5 inches to a maximum of 120 inches on a side, and VELUX Large Span glass can reach up to 10 feet in length. Custom sizes are made to order, not stocked.
To get a custom size, you (or your contractor) contact VELUX with the exact opening dimensions rather than picking a stock size code. VELUX customer service handles custom quotes at 1-800-888-3589. Because the FCM is curb mounted, it sits on a site built curb, which is what lets the size be flexible in the first place. For the standard model lineup and size codes, our VELUX skylights guide decodes the whole system.
The specialty manufacturer route (shapes and structural glass)
When you need a shape VELUX does not offer, you move from a resized stock product to a fully made to order unit from a specialty skylight manufacturer. These firms build circles, octagons, pyramids, ridge lights, and structural glass to a drawing, then ship a unit engineered for your exact curb and load.
- Marco Skylights builds custom replacement units including tandem skylights, polygons, circles, and pyramids, all made to size.
- Glazing Vision handles bespoke systems: access skylights integrated into fixed units, bi parting or stacking sliding skylights, and walkable or drive over glazing.
- CrystaLite, Supreme Skylights, and Sun Valley serve architects, custom builders, and roofing contractors with standard and custom sized glass units.
The tradeoff is cost and lead time. A bespoke shape or structural unit is engineered per project, so you get a quote rather than a catalog price, and you wait weeks for fabrication.
Why custom skylights are almost always curb mounted
Nearly every custom skylight is curb mounted, not deck mounted, because the curb is what makes a non standard size possible. A curb is a raised frame built on the roof deck to the exact opening you need. The skylight then sits on that curb, so the unit size is set by carpentry on site rather than by a fixed factory flange.
Deck mounted (flush) skylights ship with an integrated frame sized to stock openings, which is why they do not offer the same custom flexibility. The curb also raises the glass above the roof plane, which improves drainage and flashing on lower slopes. That flashing detail is also the most common leak point on any skylight, so if a custom unit ever weeps, start with our skylight leak diagnosis guide.
Lead times and how to order a custom skylight
Custom skylights are made to order, so plan for a wait. VELUX custom size FCM units typically ship in about 4 to 5 weeks. Bespoke shapes and structural glass from specialty manufacturers can take longer because each unit is fabricated to a drawing. Here is the order sequence most projects follow.
- Measure the rough opening. Get the exact width and length of the roof opening, not the room below. Custom pricing is driven by these numbers.
- Decide size vs shape. If a resized rectangle works, price a custom size unit first. Only move to a bespoke shape if the design truly requires it.
- Request a quote. For VELUX, call 1-800-888-3589 with dimensions. For shapes, send a drawing to a specialty manufacturer.
- Confirm the curb detail. Verify curb height, glass package, and flashing kit for your slope and roof material.
- Order and schedule. Place the order 4 to 6 weeks ahead of install so the unit arrives before your crew frames the curb.
When a custom skylight is worth it (and when a standard one wins)
A custom skylight is worth the premium when a stock size genuinely will not fit the opening, when the architecture calls for a shape no manufacturer stocks, or when you need structural or walkable glass. In most homes, a standard size in a curb mounted or deck mounted unit does the job for a fraction of the cost.
- Go custom size when your opening is close to a stock size but not exact, or you want a slightly larger daylight area than any code offers.
- Go custom shape when the roofline, atrium, or design demands a circle, pyramid, or polygon.
- Stay standard when a catalog size fits within an inch or two. Reframing the opening to a stock size is often cheaper than a custom unit.
Whatever route you choose, glass package matters as much as size for comfort and energy bills. Our energy efficient skylights guide covers the glazing and coatings worth specifying on a custom order.
Frequently asked questions
Does VELUX make custom sized skylights?
Yes. VELUX makes custom size skylights through its FCM (Fixed Curb Mounted) model, the most versatile unit for non standard openings. Custom sizes range from a 17.5 inch minimum to a 120 inch maximum per side, with Large Span glass up to 10 feet long. They are made to order, so you request a size quote from VELUX at 1-800-888-3589 rather than picking a stock size code.
How much do custom skylights cost?
A custom size curb mounted unit often runs about $150 to $300 per square foot for the skylight, roughly double a standard unit at $60 to $100 per square foot. A small 2 by 2 foot custom shape over an existing curb usually costs $2,500 to $3,000 installed. Bespoke structural or walkable glass reaches five figures and is quoted per project. Prices vary by region, glass package, and flashing work.
What is the difference between a custom size and a custom shape skylight?
A custom size skylight is a standard product (usually a curb mounted VELUX FCM) built to a non catalog width and length. A custom shape skylight is a made to order unit in a non rectangular form (circle, pyramid, octagon, trapezoid) from a specialty manufacturer. Custom size is the cheaper, faster route. Custom shape is engineered per project and costs more.
Do custom skylights have to be curb mounted?
Almost always, yes. The curb is a site built frame matched to your exact opening, which is what allows a non standard size. Deck mounted (flush) skylights use a factory frame sized to stock openings, so they lack that flexibility. The curb also lifts the glass above the roof plane, improving drainage and flashing performance on lower slope roofs.
How long do custom skylights take to make?
VELUX custom size FCM units typically ship in about 4 to 5 weeks because they are made to order rather than stocked. Bespoke shapes and structural glass from specialty manufacturers can take longer, since each unit is fabricated to a project drawing. Order 4 to 6 weeks before install so the unit arrives before your crew frames the curb.
Can you get a round or pyramid skylight?
Yes, through specialty manufacturers rather than the standard VELUX catalog. Firms like Marco Skylights build circles, polygons, and pyramids to size, and architectural glazing firms like Glazing Vision build walkable, sliding, and structural units. These are engineered per project, so expect a custom quote and a longer lead time than a resized rectangular unit.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.