Lead Sheet Codes

In the UK, Ireland and much of Europe, rolled lead sheet is ordered by code number rather than by millimetres. Each code corresponds to a nominal thickness and weight per square metre under BS EN 12588. Choosing the right code matters: too thin a sheet in an exposed position may split or lift, while too thick a sheet is hard to dress and wasteful.

Code table

Code	Thickness	Weight
3	1.32 mm (0.052 in)	14.97 kg/m2
4	1.80 mm (0.071 in)	20.41 kg/m2
5	2.24 mm (0.088 in)	25.40 kg/m2
6	2.65 mm (0.104 in)	30.10 kg/m2
7	3.15 mm (0.124 in)	35.72 kg/m2
8	3.55 mm (0.140 in)	40.26 kg/m2

Thickness is allowed to vary by about plus or minus 5% along the sheet.

Typical uses

• Code 3: soakers.
• Code 4: soakers, general flashings and vertical cladding; it is the usual choice for everyday flashing work.
• Codes 5 and 6: flashings, flat and pitched roofs, parapet and tapered valley gutters, dormers, bay roofs and canopies.
• Codes 7 and 8: heavier-duty flat roofs, gutters, dormers and canopies.

Marking and regional practice

Sheets should be marked with the standard, code, thickness, weight, producer and batch. Outside the UK and Europe, lead is more often specified directly by thickness or by weight per area.

Origin of the name

The code number is a practical label rather than a metric dimension, and the code system remains the everyday language of UK and Irish roofers and builders' merchants.