Why Getting Your Measurements Right Matters More Than You Think

A folding passthrough window is one of the most precise openings in a home or commercial build. Unlike a standard fixed window, every panel must fold, stack, and clear the surrounding structure without conflict. A single inch off on your rough opening width—or a counter that sits too high—can delay your project by weeks and add real cost. Getting your measurements right the first time means your custom unit ships correctly, installs cleanly, and operates flawlessly for decades.

This guide walks you through every dimension you need before you place an order for a folding passthrough window—in plain language, in the correct sequence.

What Is a Rough Opening and How Do You Find It?

The rough opening (RO) is the framed structural hole in your wall—not the finished drywall face and not the existing countertop edge. It is the measurement your custom unit is built to fit inside.

• Width: Measure from the inside face of one king stud or masonry jamb to the inside face of the opposite jamb. Take three readings—top, middle, and bottom—and use the smallest number. That is your controlling width.
• Height: Measure from the top of the rough sill (the framing member the unit will rest on) to the underside of the header above. Again, take three readings—left, center, right—and use the smallest.
• Write both in inches to the nearest ⅛ inch. Gladiator builds your unit with a standard ½-inch clearance on each side and ¼ inch at the head, so the finished frame unit will be slightly smaller than the RO you provide.

If you are cutting a new opening in an existing wall, frame it first, then measure. Never measure a chalk line or a stud layout—always measure the actual framed opening.

How High Should the Sill Be Above the Counter?

The sill height above the finished counter surface is the measurement most often overlooked, and it is critical for both function and building code compliance.

For a passthrough configuration where panels fold up and over a kitchen or bar counter, you need a minimum of 36 inches of clear sill height above the finished floor (standard bar or counter height) and a clear opening height of at least 24–36 inches depending on how wide you want the serving aperture. Taller openings allow trays, bottles, and large items to pass through comfortably.

• Measure from the finished floor to the top of your finished countertop. Standard kitchen counter sits at 36 in.; bar height at 42 in.
• Measure from the finished counter surface to the underside of your rough header. This is your usable passthrough clear height.
• In Florida, interior passthrough openings that communicate between conditioned and non-conditioned space may trigger energy code review—confirm with your local AHJ (authority having jurisdiction) if your pass-through opens to a lanai or outdoor bar.

How Do You Measure the Wall Thickness for a Passthrough Window?

Wall depth (also called the jamb depth) determines how deep the window frame must be to sit flush with—or proud of—both interior and exterior wall finishes.

• Measure from the interior finished wall surface to the exterior finished wall surface at the opening location. Include drywall, sheathing, stucco, or cladding in this measurement.
• Standard 2×6 framing with ½-inch drywall and ¾-inch stucco typically yields a jamb depth of around 7–7½ inches. Masonry block walls in Florida commonly run 8–10 inches.
• Provide this number to the Gladiator team. Custom jamb depths are standard for us—there is no upcharge for a non-standard depth because every unit is factory-built to your specs.

If you are installing into an existing masonry or CMU wall (very common in Florida construction), use a stud finder or masonry probe to confirm no hidden rebar or bond beams fall within the opening before you cut.

How Many Panels Do You Need and How Does That Affect the Width?

The number of folding panels directly drives the minimum and maximum widths that work structurally and aesthetically. More panels allow a wider opening but require a wider stacking bay at one or both sides.

• 2-panel units are ideal for openings roughly 3–5 ft wide—perfect for a beverage counter or coffee bar.
• 3-panel units suit openings in the 5–8 ft range, common for indoor-outdoor kitchen passthroughs.
• 4-panel units work well up to about 10–12 ft for large outdoor bar or restaurant servery applications.

Each panel must have a clear place to stack when open. Measure the available wall space beside the opening on the stacking side. You need at least the width of one panel (roughly ¼ to ⅓ of the total opening width, depending on panel count) of clear, unobstructed wall. Cabinets, outlets, and light switches on that wall need to be relocated before installation.

Our folding passthrough window collection covers a range of panel configurations—share your RO width and we will confirm the optimal panel layout for your opening.

What Other Dimensions Should You Record Before Ordering?

Beyond width, height, and wall depth, a complete measurement checklist for a folding passthrough window includes:

• Soffit or cabinet clearance above: If upper cabinets or a soffit run close to the header, measure from the finished header face down to the cabinet bottom. Panels that fold up need clear overhead travel room—or a fold-down configuration must be specified instead.
• Counter depth (front to back): A standard 25-inch-deep counter is fine. Deeper commercial bar tops (30+ inches) may affect how far a customer or guest can comfortably reach through the opening—worth noting when choosing sill height.
• Exterior finish plane: Note whether the exterior side will be flush with a stucco face, set into a reveal, or trimmed with a surround. This affects how the exterior stop is detailed.
• Swing direction (fold in or fold out): Panels can fold to the interior or exterior. Most residential kitchens fold to the exterior so the counter stays clear. Measure outdoor clearance to confirm panels won't conflict with a pergola, overhang, or railing.
• Glass type needed: Florida's wind-borne debris region requirements may mandate impact-rated glass. Confirm your county's requirements. Gladiator's passthrough windows are available with impact-rated laminated glass to meet Florida Building Code wind speed maps.

How Do You Format Your Measurements When Ordering?

When you contact Gladiator, provide measurements in this format so nothing is lost in translation:

Dimension	What to Measure	Example
Rough Opening Width	Framing face to framing face (smallest of 3 reads)	72 ⅜ in.
Rough Opening Height	Sill framing top to header underside (smallest of 3 reads)	38 ¼ in.
Jamb Depth	Interior finish face to exterior finish face	7 ½ in.
Sill Height AFF	Finished floor to top of counter surface	36 in.
Stacking Side	Left or right when viewed from interior	Right
Fold Direction	Interior or exterior	Exterior
Glass Requirement	Impact / non-impact / low-E spec	Impact laminated, Low-E

Double-check every number against the framed opening itself—not architectural drawings, which often differ from field conditions by ¼ to ½ inch.

Can a Folding Passthrough Window Work Alongside Other Door Systems?

Yes, and it often does. Many Florida homeowners pair a folding passthrough window with bi-fold doors or sliding glass doors on the same outdoor living wall to create a fully open kitchen-to-lanai experience. When planning multiple openings on one wall, measure each rough opening independently and note the distance between them (stud bay to stud bay) so the frames can be coordinated in the same aluminum finish. Gladiator's thermal-break aluminum profiles are available in the same finishes across all product lines, so everything reads as a cohesive system.

If your project also includes exterior shade, an aluminum pergola overhead ties the entire indoor-outdoor zone together and keeps direct rain off the passthrough counter—a practical detail in Florida's afternoon storm season.

Ready to Order? Here's the Next Step

Once you have your measurements in hand, our team can confirm the optimal panel configuration, glass spec, and frame finish for your project—with no dealer markup, because every unit ships direct from our Jacksonville factory. Browse our folding passthrough window collection or reach out with your measurements and we will send a formal quote, typically within one business day.

Frequently Asked Questions