Bitumen sheets are light, small and easy to cut, and suit sheds, garages, stables and other outbuildings. Big 6 fibre cement is a heavier, larger sheet with a Class A1 fire rating, used on barns, livestock buildings and larger roofs.
What each sheet is made from
Bitumen sheets are made from organic fibres saturated in bitumen. They are rot-resistant and lightweight, and the product pages describe them as easy to handle and install. Big 6 is a fibre cement sheet that Briarwood makes at its own plant in Italy and holds in stock at Highbridge, Somerset. Both can be used on roofs, and both can also be used as wall cladding.
Size and weight
A bitumen corrugated sheet is 2000 mm long and 930 mm wide, with an 837 mm cover width, and weighs 5.4 kg. That is about 2.9 kg per square metre of sheet area, before laps. Big 6 is 1086 mm wide with a 1016 mm cover width, comes in lengths from 1525 mm to 3050 mm and weighs 18 kg per square metre.
Fixing and framing
Bitumen sheets are 2.2 mm thick and are cut with basic tools. They are nailed at about every second corrugation across the sheet and at every purlin, into timber purlins or OSB boards.
Big 6 is 6.5 mm thick. It is pre-drilled, fixed with two fixings per sheet per purlin, and needs purlins at most 1375 mm apart.
Pitch
Both have a 5 degree minimum roof pitch. Bitumen sheets suit pitches from 5 up to 90 degrees. Between 5 and 10 degrees Big 6 needs 300 mm double-sealed end laps and slopes no longer than 15 m.
Fire and condensation
Big 6 is Class A1 for reaction to fire.
Bitumen sheets support ventilation at the roof overhangs, which helps reduce condensation. Big 6 absorbs and releases moisture, which helps reduce drips in livestock buildings.
Colours and guarantee
Bitumen sheets and their accessories come in Black, Green and Red. Big 6 comes in seven colours. Big 6 sheets are guaranteed for up to 30 years.
Where each is used
Bitumen sheets are used on sheds, garages, stables, workshops and other outbuildings, and on some agricultural buildings. Big 6 is used on barns and livestock housing, equestrian buildings, industrial and commercial units, and domestic outbuildings.
How to choose
- Choose bitumen for a small outbuilding where light weight, simple cutting and a nailed fixing into timber suit the job.
- Choose Big 6 for a larger roof, a livestock building, or where a Class A1 fire rating and a 6-inch profile matter.
- To count the sheets across the roof, divide the roof width by the cover width, 837 mm for bitumen or 1016 mm for Big 6, and round up.
Accessories and delivery
Bitumen ridge capping, barge boards, fixings and foam eave fillers are small parcel items, delivered in 1 to 3 working days. Bitumen sheets and Big 6 sheets are delivered by lorry to the kerbside in an estimated 6 to 10 working days, to England, Wales and mainland Scotland, and unloading assistance is required. You can also collect free from Highbridge.
See the ranges: bitumen corrugated sheets and accessories and Big 6 fibre cement sheets. For help, call 01278 228670 or email [email protected].