Measuring New Double Glazing Units

[jam00]

HI All

I need to replace a few Double Glazing Unit just the Glass not the frames, I am right in saying I can measure them by starting point with the tape measure where the beading meets the frame then finish where on the other side where the beading meets the frame to get the correct size then minus 10mm of the measure.

Many thanks

 

[crank39]

Correct, although i once got caught out on a very old Anglian window, it transpires there is a 5mm step in their profile and i lost the 10mm gap i needed, infact i could of knocked off 20mm and still had plenty of cover