When laying Bradstone Infilta concrete block permeable paving, conventional MOT Type 1 is not used in the sub-base as it is not free draining, the Bradstone 20mm open graded drainage is used.
In free draining applications, a suitable geotextile should be placed at formation level (overlapping joints by 300mm), below the Drainage Aggregate sub-base. When the sub-base is designed to hold water an impermeable memebrane lining should be used.
The depth of the sub-base will be governed by the strength and type of the underlying ground, but typically you will need to be around 200mm deep on soils of good strength and 500mm in areas of poor soil strength.
It is best to prevent vehicles running on the sub-base during construction if possible, as they will cause rutting in the loose surface. The blocks are restrained in the conventional way with a kerb or edging and provide more than adequate support to traffic.
Laid to a depth of 200mm, 1 Bulk Bag covers 2.85m2
