Laying Courses, Fixings and Ridge Cops

Courses go up the slope at 200-250 mm spacing, fixed at 150-200 mm centres; the ridge is twisted into cops 400-500 mm wide.

Laying starts after the strip-back: 300-400 mm of weathered thatch has come off each slope, and the new material goes over the sound thatch that remains. Straw is laid from bales of about 300-400 mm; long reed is supplied at roughly 1.5-2.5 m.

Courses are spaced 200-250 mm apart up the slope. Each course is fixed with 1.6 mm (16 gauge) galvanised wire or with hazel rods around 13 mm thick, driven at 150-200 mm centres across the course.

The ridge is built separately, from bundles twisted together into cops. A reed ridge is normally 400-500 mm wide at the base and 300-400 mm deep, and it is held down with its own straw and fixings.

The finished build-up adds about 300-600 mm to the overall depth of the roof. Throughout, the covering stays ventilated at the eaves and ridge rather than being closed with bitumen felt.

Once laid, the work goes onto its maintenance cycle: the ridge is due for renewal in 8-12 years on reed or 5-8 on straw, while the covering itself lasts 40-60 years on reed or 15-25 on straw, given a well-ventilated roof of at least 45-50 degrees pitch.

• Strip back 300-400 mm per slope to sound thatch.
• Lay courses at 200-250 mm spacing up the slope.
• Fix at 150-200 mm centres: 1.6 mm wire or 13 mm hazel rods.
• Twist ridge bundles into cops: 400-500 mm base, 300-400 mm deep.
• Keep eaves and ridge ventilated; no bitumen felt.

Further reading

• When to Strip Back and When to Revet
• Water Reed vs Wheat, Oat and Barley Straw