How to Measure for Supply-Only Windows

Measure the structural opening at three points across the width and height, take the smallest of each, then deduct the gap your supplier specifies for packers and sealant, commonly around 5 to 10 mm per side. Confirm whether the order is for the frame size or the opening size.

What is the measuring routine?

Measure the width at the top, middle and bottom of the opening and use the smallest figure
Measure the height at left, centre and right and use the smallest figure
Check the opening is square by comparing the diagonals
Record the cill depth and whether a sub-cill or cill is needed
Note the opening handing as seen from outside
Specify glass, vents and any egress or PAS 24 requirements

Which mistakes cause remakes?

Measuring the old frame instead of the opening
Not reducing for the fit gap
Mixing up left and right handing

Can you get help with sizing?

Send us your schedule of sizes and the trade counter in Worthing can check it before you order. See our supply-only uPVC windows. Never rely on the old frame size as the opening size, as plaster and cills can hide a different structure.

Need a trade price? Call the trade counter on 01903 262 636 or visit us at Unit 1, Friar Walk, Worthing. We offer free delivery within 30 miles.

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MLI Building Products LTD

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Peter Hughes

2 years ago

Davyd Oddy

3 years ago

Great service and products from super friendly staff. Specials thanks to Loretta and Stephen

Stephen Gale

4 years ago

Great service good bunch lads

Response from the owner

4 years ago

Thanks Steve.

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4 years ago

Kimberleyjanep

4 years ago

So helpful - Steve was so patient while I chose my new front door - which was installed by PBM Exteriors who recommended MLI. I cannot emphasise how much my new and very contemporary front door makes the house look so modern and 'new'. Just huge thanks for great service and an amazing grey anthracite grey front door and side panels!

Response from the owner

4 years ago

You were very welcome Kim. It was our pleasure.

Elliott Prior

5 years ago

Response from the owner

5 years ago

Thank you Elliott

Richard Jones

5 years ago

Great people to do business with!

Response from the owner

5 years ago

Thank you Richard.

penelope strachan

6 years ago

So pleased I found MLI to supply the windows and doors for my property renovation, Excellent Prices, far more competitive than any other quote I had. Service from Steve & Loretta was amazing, nothing was too much trouble. Everyone compliments us on the fantastic windows. I highly recommend. Thank you so much

Response from the owner

6 years ago

Hi Penelope. Thank you very much. 👍🏻