Beads, coving and sundries
Angle bead and stop bead lengths
- where
- angle bead length (m)
- external corners, full height
- corner height (m)
- openings with beaded reveals
- opening height (m)
- horizontal beaded edges per opening (1 = head, 2 = head and sill)
- opening width (m)
- angle bead lengths to buy
- bead stock length (m)
- stop bead length (m)
- stop bead runs
- length of each stop bead run (m)
- stop bead lengths to buy
Explain this equation
This works out the total angle bead for external corners and reveals and the stop bead for plaster edges, and how many stock lengths of each to buy.
nc corners of height hc each take a run of bead. Each of the no openings has two jambs of height ho and k horizontal edges of width wo (the head, and the sill if it is plastered). Stop bead is ns runs of length ls. S is the length the bead is sold in.
Lengths are simple sums of every beaded edge. The number to buy is worked out run by run, rounding each one up to whole stock lengths, because an offcut from one corner rarely fits another.
Sense check: two 2.4 m corners and two 1.2 m square windows with heads beaded need 12 m of angle bead, but eight 3 m lengths, not four, because each jamb and head is a separate cut.
Watch out: if openings differ in size, run the calculator once for each size and add the results.
Total angle bead for external corners and window or door reveals, and stop bead for plaster edges, counted per run so each run is a whole length where possible.
Enter your values to see the result.
Good to know
Thistle thin-coat angle and stop beads come in 2400 mm and 3000 mm lengths (other makers also 2700 mm). Each corner or reveal edge is counted separately because a short offcut is rarely usable on another corner. Door openings normally have two jambs and a head (k = 1); windows with a plastered sill take two horizontal edges (k = 2).
Common mistake
Ordering by total length divided by stock length. A 2.5 m corner with 3 m bead leaves a 0.5 m offcut that is no use on the next 2.5 m corner.
Limits
Assumes every opening is the same size; run the calculator again for each size. Joins in long runs are not optimised.
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the manufacturers’ system and product data, BS 8212, BS EN 13914 and Building Regulations. Coverage rates vary by product, background and thickness. Check prices, VAT and CIS rules with your own records and HMRC.