How to Measure for Skylight Blinds: A Foolproof UK Guide

Ordering custom-made skylight blinds online is the best way to ensure a flawless fit, maximum light control, and superior thermal insulation for your loft space. However, achieving that seamless, built-in look relies entirely on one crucial step: taking accurate measurements.

Unlike standard off-the-shelf blinds, bespoke roof blinds are manufactured to your exact specifications. If you measure correctly, installation will be a breeze, and you will eliminate annoying light gaps. Here is the ultimate step-by-step guide to measuring your skylight windows like a professional.

The Golden Rule: Measure Plasterboard to Plasterboard

The most common mistake homeowners make is measuring the visible glass area or the wooden window frame. For a true blackout experience and a flush finish, you must measure the recess.

This means placing your tape measure against the inner edges of the plasterboard surrounding the window opening. Your blind will sit neatly within this plasterboard reveal, blocking light before it even enters the room.

Step 1: Gather the Right Tools

• A Metal Tape Measure: Never use a cloth measuring tape, as they can stretch and warp, leading to inaccurate readings. A sturdy metal retractable tape measure is essential.
• Pen and Paper: Write down the measurements immediately to avoid mixing up the width and the length.
• A Step Ladder: Ensure you can safely reach the highest points of your roof window recess.

Step 2: Measuring the Width (W)

• Place your metal tape measure horizontally across the recess, from the left plasterboard edge to the right plasterboard edge.
• Measure the width in three different places: at the top, across the middle, and at the bottom.
• Crucial Step: Note down the smallest of these three measurements. Houses settle, and plasterboard is rarely perfectly square. Using the smallest width ensures the blind cassette will fit smoothly into the recess without getting stuck.
• Note on limits: Custom skylight blinds typically accommodate a minimum width of 450mm and a maximum width of 2000mm.

Step 3: Measuring the Length (L)

• Now, measure vertically from the top plasterboard edge down to the bottom plasterboard edge.
• Measure the length in two different places: down the left side and down the right side.
• Once again, write down the smallest measurement.
• Note on limits: Lengths generally range from a minimum of 450mm up to a maximum of 4000mm.

Important UK Manufacturing Standards to Remember

• Always Use Millimetres (mm): The UK manufacturing industry operates strictly in millimetres. Providing your measurements in centimetres (cm) or inches can lead to catastrophic conversion errors. If your measurement is 120cm, record it as 1200mm.
• Do Not Make Any Deductions: Provide the exact, “tight” recess size. Do not subtract any millimetres to account for brackets or clearance. The manufacturing team will automatically make the necessary micro-adjustments to ensure your blind operates smoothly within the space you have provided.

By following this simple plasterboard-to-plasterboard method and double-checking your millimetres, you can order your motorised or manual skylight blinds with absolute confidence.