Top-over lashing (friction lashing) step by step

The load must be restrained against 0.8 g forwards (braking), 0.5 g sideways and 0.5 g backwards, with the safety factors f_s = 1.25 forwards and 1.1 sideways/backwards and vertical coefficient c_z = 1.0. The forward direction is the governing one, because the braking force is greatest.

Friction carries the most weight in the formula: the higher the µ, the fewer lashings. Read off a realistic value for the material pair (e.g. sawn timber ↔ plywood ≈ 0.45, timber ↔ steel ≈ 0.30), and choose conservatively with moisture or smooth surfaces. An anti-slip mat raises µ to approx. 0.6.

Place the load right up against the headboard and against each other so that it is blocked in the direction of travel before you lash it. Lay anti-slip mats underneath where the surface is slippery. The more the load holds itself, the less the lashing has to cope with.

Place the strap over the load so the vertical lashing angle α is as close to 75–90° as possible. An almost horizontal strap only gives a small downward pretension component and works poorly as a frictional lashing.

Read the Lashing Capacity (LC) and the pre-tension force STF directly from the strap's label (EN 12195-2). Never guess these values — the calculation is based on them, and they must be documentable at inspection.

Never confuse LC (lashing straps, EN 12195-2) with WLL from lifting gear.

Calculate the required number with the friction lashing equation in DS/EN 12195-1 (EQ10): n = ( m · f_s · (c_xy − µ·c_z) · g ) / ( 2 · µ · STF · sin α ). Use the Discebo «Load securing» calculator — it rounds up conservatively and flags if friction alone is sufficient, or if the lashing is physically impossible.

If (c_xy − µ·c_z) ≤ 0, friction alone holds against sliding — but still lash against tipping and unintended movement.

Tighten the ratchet tensioner so the strap reaches its STF, and fit edge protectors at all sharp corners the strap crosses. The edge protectors protect both strap and load and help the pretension all the way round.

Check and retighten the straps after approx. 50–100 km (the load settles) and after any hard braking or unexpected manoeuvre. Keep the lashing plan/calculation as documentation for roadside checks.