The serving window is the face of your concession trailer. Cutting that opening into a perfectly good trailer side can feel intimidating, but if you follow a simple sequence, it becomes a clean, controlled job instead of a hacking session.

Start With the Window Manufacturer’s Dimensions

Don’t guess. Get the exact cutout measurements from the manufacturer of the window you’re installing. These dimensions are typically slightly smaller than the overall frame size so the flange has something to grab.

Marking the Opening

Use tools that help you stay accurate:

Painter’s tape to outline the opening.
A level to keep the window level to the trailer, not the ground you’re parked on.
A tape measure and straightedge or chalk line for long cuts.

Double-check the position from inside and outside the trailer. Make sure you’re not cutting through structural frame members you still need.

Cutting the Skin

A common approach is to start the opening with an angle grinder and finish with a reciprocating saw:

Use the grinder to make clean starter cuts at the corners.
Switch to the reciprocating saw to cut along the marked lines.
Support the panel as you finish the last cuts so it doesn’t tear away.

Take your time. A clean opening saves you hours of trim and sealing work later.

Framing the Opening

Once the skin is cut, you need to frame the opening to support the window:

Use steel tube, angle, or solid wood framing sized to fit behind the opening.
Secure the frame to the trailer structure with self-tapping screws or bolts.
Make sure the frame is square and level so the window doesn’t bind.

Sealing and Installing the Window

Before you set the window in place:

Apply butyl tape around the window flange area.
Set the window carefully into the opening from the outside.
Fasten according to the manufacturer’s pattern, tightening gradually and evenly.
Finish with a clean bead of exterior-grade sealant around the perimeter.

Awning Arms and Customer Safety

If your window includes awning arms, make sure they:

Hold the awning securely in the open position.
Don’t create sharp corners at head height for your customers.
Operate smoothly when opening and closing.

A careful window cutout and installation makes your trailer look professional and keeps the weather out. Take your time on this step, and your serving window will be a strength instead of a weak spot.