1. Measurement of opening
Check opening for square by measuring diagonals. Measure reveal several times in both the height and the width. In each case use the smallest measurement and take off a further 6mm (3mm all round) to give the aluminium frame size. This is based on the use of the standard 33mm x 15mm S/W ground.
2. Interlock positions
Check position for interlocks on sliding units. Equal sized sashes will be produced unless otherwise stated. Note the standard configuration for two pane sliding units (Series 10 and Series 80) has the right hand sash room side.
3. Face fixed detail (Series 10, 20, 30, 40, 45)
When measuring to lip a timber-frame take tight internal timber size and add 25mm to give aluminium frame size. This will provide a 3mm overall fitting tolerance. Note that when fixing a Series 20 vertical sliding unit a minimum 80mm glass to glass cavity is desirable to allow for cleaning.
4. Multiple units
If two or more secondary windows are to be coupled together in a single opening, measure from the frame edge to the centre of the transom/mullion line and allow a further 2mm tolerance if the standard Selectaglaze coupling section is specified.
Each window must be ordered separately.
5. Casement hinging
Indicate hinge side as viewed from inside.
Indicate handle height from frame edge to centre position.
It is advisable to increase tolerances when measuring for large sash or side hung Casement windows. Also, where the difference in diagonal measurements exceeds 6mm, determine maximum true rectangle which will fit.