Sash window bead calculator
Enter your window sizes and get the staff bead, parting bead and brush seal you need, cut into the fewest lengths and priced at today's prices.
1 Your windows
Timber frame opening in mm: width side to side, height sill to head.
Paste a list from a spreadsheet
2 What you are fitting
Bead sizes and extras
3 Your list
How we work it out
Double hung (sash) windows
- Staff bead: four pieces, two sides at the height and the head and bottom at the width, cut to the long point of the mitre.
- Parting bead: two sides at the height, and the head at the width + 10mm so it sits into the rebate.
- Brush and seal: the length of each run + 100mm, + 5%, rounded up to whole metres.
Lengths and packs
- Pieces are fitted into stock lengths with the fewest lengths we can find, allowing 3mm per saw cut and 10mm to square the end.
- Then we price every pack size we sell, singles, 10-packs, rolls and kits, and pick the cheapest mix at today's prices.
- If a kit covers your window for less than the loose parts, we show you both and say which is cheaper.
Common questions
What is the difference between staff bead and parting bead?
Staff bead (stop bead) runs around the inside of the frame and holds the bottom sash in. Parting bead sits in a groove between the two sashes and keeps them apart. Ours have a track built in for the draught seal.
What sizes do your beads come in?
Staff bead is 15mm thick, 20mm or 25mm deep, in 3.0m lengths. The staff bead for A10 compression seal is 15 x 20mm in 4.2m lengths. Timber parting bead is 8 x 25mm in 3.0m lengths. All are primed white.
Which brush seal do I need?
Pick a brush 1 to 2mm taller than the gap so the fins stay in contact. A 3 to 4mm gap takes 5.5mm brush, 5 to 7mm takes 8.5mm, and 8 to 10mm takes 11.5mm. If the gap changes along the window, size for the widest point.
How much parting bead do I need for one window?
Two sides at the frame height, and one head piece at the frame width plus 10mm to sit into the rebate. A typical 900 x 1600mm window needs two 3.0m lengths.
Can I share this list with my builder or get a trade price?
Yes. "Copy link to this list" saves every window in the link, and it is re-priced each time someone opens it. Trade customers can email the list to us for a quote.