Finishing
Tile trim lengths to buy
- where
- total trimmed edge (m)
- edge lengths (m)
- trim lengths to buy
- length of one trim (m)
Explain this equation
Works out how many lengths of tile trim to buy for up to four separate edges, and the total trimmed length.
E1 to E4 are the lengths of each edge that needs trim and Ls the length of one trim as sold, usually 2.5 m in the UK. Lt is the total trimmed length and N the lengths to buy.
Each edge is rounded up separately with the ceiling brackets, so each edge is made from whole lengths cut down, with as few joins as possible. Adding the edges first and then dividing would assume offcuts can be joined on another edge, which looks poor.
Sense check: two 2.4 m edges and one 1.2 m edge need three 2.5 m trims, leaving 1.5 m of offcut.
Watch out: allow a little extra where corners are mitred, and check the stock length of the trim you are buying.
Number of trim lengths for up to four separate edges, buying whole lengths per edge so each edge has as few joins as possible.
Enter your values to see the result.
Good to know
Standard UK aluminium and PVC trims (Genesis, Schlüter and others) come in 2.5 m lengths. Joins look better at a corner than mid-run, so each edge is rounded up separately. Corners need either mitring (allow a little extra) or matching corner pieces. Choose a trim height to suit tile thickness plus adhesive bed.
Common mistake
Totalling all edges and dividing by 2.5, which assumes offcuts from one edge can be joined on another and leaves visible joins.
Limits
Offcuts may still be reused on short returns, so the count is conservative. Check stock lengths for your chosen trim (some are 2.44 m or 3 m).
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the tile, adhesive and grout manufacturers’ instructions, BS 5385 and the Tile Association guidance. Coverage rates vary by product and substrate. Check prices and VAT rules with your own records and HMRC.