Size of slate

600mm x 300mm x 4mm

Minimum pitch

17,5ᴼ (Marley Radiant Barrier Compulsory in all cases when used as roof covering)

Maximum pitch


Typical headlap

+ - 360mm depending on lap


110mm (pitches 17,5°- 30°), 100mm (pitches 30°- 35°), 90mm (pitches >35°), Lap = for gauging rivet placement - distance of bottom rivet from centre of batten

Batten gauge

245mm (lap 110mm), 250mm (lap 100mm)

Covering capacity

13,6 slates/m² (net) for lap 110mm, 13,4 slates/m² (net) for lap 100mm

Weight per m²

+ - 20,9 kg/m² for 110mm lap, + - 20,4 kg/m² for 100mm lap,

Battens required

4,08 lin.m/m² for 110mm, 4,00 lin.m/m² for 100mm

Batten Size Recommended

38 x 38mm for rafters/supports not exceeding 760mm centres. 38 x 50mm (batten fixed flat) for rafters/supports not exceeding 900mm centres. Note: Above 760mm the rafter spacing can be increased only with engineerdesigned trusses and with 38 x 50mm batten of the correct grade. All structural timber must comply with the relevant requirements of SANS 1460, SANS 1783-2 or SANS 1783-4, SANS 1707-1 or SANS 1707-2 and be structurally graded and stamped (in signal red or black) with the appropriate grade mark.


Bottom of slate fixing (All Regions) - Copper disk rivets. Batten fixing (Coastal Regions)- 40mm Copper Nails. Batten Fixing (Inland Region) - 40mm Galvanised Nails. Ridge fixing (Coastal Region) - 50mm Copper Clout Nails. Ridge fixing (Inland Region) - 50mm Galvanised Nails.


Maximum wind suction loading = 2000N/m² **When using two 30mm x 2.65mm long copper nails with copper disc rivet (19mm x 2mm stem, 19mm dia x 0.5mm thick base)

Additional notes

• Use broken-bond practice only! • Marley Radiant Barrier is compulsory for pitches below 26 degrees in all cases and Radiant Barrier or Undertile Membrane is compulsory for any pitch above 26 degrees and in all cases. • Ensure that all battening is in an absolute level plane! The aesthetic end-result and water tightness is dependant on good workmanship as well as level battening and well aligned trusses. • Marley Alterna Slates are not suited for screw fixing to metal battens. In the case of light steel frame, wooden battens would be required. • Slates should be scored using a scribing tool and snapped over a straight edge and should not be cut with a slater’s axe. • Slates can be cut using a normal handsaw/hacksaw with teeth of 3mm - 3.5mm pitch, preferably wide set. Saws should always be used to start off when cutting acute angles. • Additional fixing holes should be drilled using a 4.0mm dia. standard drill bit. Fixing holes must not be punched. • In all cases, dust or swarf should be removed immediately from the slate edge, to reduce the possibility of cement staining when the slate is first wetted by rainfall. • As this product is made of mainly mineral raw materials, it can contain traces of quartz. Mechanical machining (cutting, sanding, drilling) of this product can release dust which may contain quartz particles. Always apply the appropriate general and personal protective measures when mechanically machining these products: 1. Avoid generating airborne dust by using tools with dust extraction and/or suppression. 2. Guarantee adequate ventilation in the workplace. 3. Wear the appropriate personal and respiratory protection to avoid inhalation of dust and contact with eyes and skin. All slating and fixing to comply with 10400L code of practice.

Blue Black (manufacturers name - looks like slate / charcoal)

Please note, colours are as accurate as screen resolution allows, please view physical samples before deciding on final colour of your roof.

View and download literature

Marley Alterna Fibre Cement Brochure

Marley Alterna Fibre Cement Slates

Marley Alterna Slates provide the best-in-class Fibre Cement roofing and cladding solutions, that meet the highest performance in durability and aesthetics.

Available in all regions



  • Modern Aesthetic - produces a clean modern roof line.
  • A highly cost-effective alternative to natural slate.
  • Ultimate Assurance - Service lifespan of over 30 years.
  • Extreme Durability - The siliconized coating provides a highly durable surface finish that is water repellent.
  • Cool Roof Solution - Unaffected by a range of climatic temperatures (-20 to 70 Degree Celsius)
  • Ultra Versatile - Non-combustible with unrestricted usage for walls and roofs.
  • Superior Strength - High density and  fibre content.