6 x 1 inch treated timber

“6 × 1” is the traditional imperial designation for timber formerly supplied at 6 inches by 1 inch. Since the UK’s move to metric, timber is specified in millimetres.

• Nominal imperial size: 6" × 1" (≈ 152.4 × 25.4 mm)

• Nominal metric reference: 150 × 25 mm

• Typical finished size after drying and planing:

  • Planed (PSE/PAR): ≈ 18–19 mm × 144–146 mm

  • Sawn: ≈ 22–25 mm × 147–150 mm
    (Actual supplied dimensions vary by mill, moisture content, grading, and finish.)

The legacy “6×1” label persists for convenience, but specifications, drawings, and cutting lists should use the metric finished size. For tight tolerances or when matching existing work, measure the section received. Lengths are supplied in metres.