A flat concrete slate which can be laid at pitches as low as 17.5. Our most economical concrete slate with interlocking edges for simple construction. An economical concrete slate, Mini Stonewold has interlocking edges ensuring quick and simple construction, reducing the laid cost of the roof. As with all of Redland's slate range, full compatibility with a range of dry-fix fittings and accessories gives additional peace of mind. Properties Size: 418mm x 334mm. Minimum pitch: 17.5 at 100mm headlap. 22.5 at 75mm headlap. Maximum pitch: 90. Maximum headlap: 125mm. Minimum gauge: 293mm. Maximum gauge: 318mm below 22.5. 343mm 22.5 and over. Tile thickness: 31mm. Coverage: 10.7 slates/m2 at 318mm gauge. 9.9 slates/m2 at 343mm gauge. Weight: 5.10 tonnes/1000. Batten size: 38mm x 25mm - rafter centres up to 450mm. 50mm x 25mm - rafter centres up to 600mm. Battens required: 3.15m/m2 at 318mm gauge. 2.92m/m2 at 343mm gauge. Nail size: 50mm x 3.35mm. Slate finish: smooth - through coloured. Certification BBA certified.