Mark. You need to measure the width and height of each sudg unit from the point that the bead touches the frame and then deduct 5mm off EACH dimension. Expect to pay between £25 to £60 per sq/m depending on type eg tough K obscure is most expensive.
Ahh.. now to the thickness. The spacer tubes (silver bit) come in varying sizes, and can usually be i.d'd by how old they are. Modern (last 8 or so years are 24 or 28mm) but older ones can be 12,14,16,18,20 so best to take one out and measure - you'll have to do it when you replace anyway! The glass is usually 4mm so an 18mm unit is known as 4-10-4. Hope this helps. Kev
kev, April 2007
