How to Measure a Window in a Brickwork Reveal

Teign Trade Frames – Window Measuring Guide

1. Tools You’ll Need

• Tape measure (millimetres preferred)

• Notepad and pen/pencil

• Spirit level (optional, for checking squareness)

• A clear view of the brick opening

2. Measure the Width (Brick-to-Brick)

• Take 3 measurements across the width:

  • One at the top

  • One at the middle

  • One at the bottom

• Measure brick-to-brick, not frame-to-frame.

• Record the smallest of the three values. This ensures the window will fit within the tightest part of the opening.

3. Measure the Height (Brick-to-Brick)

• Take 3 measurements from the top of the brickwork (underneath the lintel) down to the bottom brick course or cill:

  • One on the left

  • One in the centre

  • One on the right

• Again, record the smallest of these three height values.

4. Check for Squareness (Optional but Recommended)

• Measure diagonally from top-left to bottom-right, and then from top-right to bottom-left.

• If the difference between the two diagonal measurements is more than 5 mm, your opening may be out of square. This might require additional fitting tolerance.

5. Apply Fitting Tolerance

To allow room for fitting, sealing, and any irregularities in the brickwork, deduct:

• 10 mm from the width

• 10 mm from the height

This gives your final window size to order.

6. Depth / Profile Considerations (Optional)

Measure the depth of the brickwork reveal from outside to inside. This helps:

• Ensure you order the correct frame thickness

• Plan any internal finishing (such as plaster returns or trims)

Standard uPVC windows are usually 70 mm deep, but checking the reveal depth is helpful if you have unusual wall construction.

7. Final Notes for Ordering

When placing your order, clearly state:

• The final width and height after deduction

• Whether you’ve measured brick-to-brick

• If a cill is required, and whether it’s included in your height

• The style of opening (top opener, side opener, fixed, etc.)

• The location and any special requirements (e.g. toughened glass)

Measurement Summary Checklist

1. Clear away any obstructions around the window

2. Measure width (top, middle, bottom) – record the smallest

3. Measure height (left, middle, right) – record the smallest

4. Subtract 10 mm from width and height

5. Optional: check depth of reveal

6. Confirm squareness if needed

7. Double-check your figures before ordering