20/11/25

How to Take Accurate Measurements for PVC Windows

Precise measurements are essential for proper PVC window installation. Errors can lead to drafts, misalignment, and extra costs. Here’s a step‑by‑step guide to measure your opening correctly.

What you’ll need:

• tape measure (5–7 m);
• level (laser or spirit);
• notebook and pen;
• camera (to document the opening’s features).

Step 1. Preparation
Clear the area around the window. Remove curtains, furniture, and any obstructions.

Step 2. Measure the width

• Take three readings: at the top, middle, and bottom of the opening.
• Record the smallest value.
• Subtract 2–6 cm for mounting gaps.

Step 3. Measure the height

• Take measurements on the left, in the centre, and on the right.
• Note the smallest value.
• Deduct 2–3 cm at the bottom (for the sill plate) and 1–2 cm at the top (for expansion gaps).

Step 4. Check the geometry

• Use the level to detect any vertical or horizontal deviations.
• Pay attention to rebates (ledges): if present, add 2–3 cm on each side for the window fit.
• Mark any irregularities or distortions — they affect final dimensions.

Step 5. Record the data

• Carefully write down all values.
• Label each measurement (width, height, notes).
• Photograph the opening from different angles.

Key tips:

• Measure inside the opening.
• Consider the windowsill and drainage sill if they remain in place.
• If in doubt, consult a professional: a 5–10 mm error can compromise installation.

Conclusion:
Accurate measurements save time and money. Take your time — double‑check every dimension.