About IN-ALU-DOOR

How to Measure for Your IN-ALU-DOOR

Accurate measurements are essential to ensure your new internal aluminium door fits seamlessly. Because our doors are crafted with precision-engineered aluminium profiles, measuring your opening correctly will ensure a smooth and straightforward installation process.

Follow this simple 3-step guide before placing your order.

What You Will Need

A quality tape measure (preferably steel, not fabric)
A spirit level
A notepad and pen
Measurements in millimeters (mm) for maximum accuracy

Step 1: Check that Your Opening is Square and Level

Before measuring dimensions, check that the structural opening is level and true.

Check vertical level: Place your spirit level against the left and right inner walls (jambs).
Check horizontal level: Place your spirit level across the top opening (lintel) and bottom floor.
Check squareness: Measure diagonally from the top-left corner to the bottom-right corner, then from the top-right corner to the bottom-left corner.
- If both diagonal measurements are equal, your opening is square.
- If they differ by more than 5mm, your opening is out of square. Use the smallest measurements when ordering, or consult a builder to square the opening first.

Step 2: Measure the Structural Opening (3-Point Measurement)

Always measure the structural brickwork or studwork opening where the door frame will sit, not an old timber frame (unless you are fitting inside an existing frame).

A. Width

Measure the horizontal width at three places:

Top of the opening
Middle of the opening
Bottom of the opening

👉 Record the SMALLEST measurement.

B. Height

Measure the vertical height at three places:

Left side
Center
Right side

👉 Record the SMALLEST measurement.

Step 3: Calculate Your Ordering Size (Deduct Fitting Tolerances)

To ensure the door frame glides smoothly into place without binding against uneven walls, you must deduct a fitting tolerance from your smallest measured dimensions:

Width: Deduct 5mm from your smallest width measurement.
Height: Deduct 5mm from your smallest height measurement.

Example: > * Smallest measured width = 850mm ➔ Order Width = 845mm > * Smallest measured height = 2050mm ➔ Order Height = 2040mm

This extra 5mm gap around the frame perimeter allows for easy adjustment, leveling, and perimeter sealing during installation.

Important Considerations Before Ordering

Finished Floor Level: Ensure you measure from the final finished floor level (e.g., after tiles, hardwood, or carpet are laid). If flooring is not yet installed, allow for its total thickness in your height calculations.
Plastering/Skimming: Take measurements after walls are fully plastered and finished.
Handing & Opening Direction: Decide whether your door needs to open inward or outward, and whether it hinges on the left or right (viewed from the primary room).