Technical Information
General Technical Data
On porous ground, and where there are adjacent flower beds and / or lawns consideration should be given to leave gaps at suitable intervals along the haunching to allow the bedding course to additionally drain into those planted and soft landscape areas.
If there is cause for concern that standing water will soften the sub-base in an unlined system, a nominal fall to an outfall should be considered. Occasionally if the sub-base is silty or plastic it may be necessary to stabilise it or partially replace it with a granular capping. The total depth of the sub-base may be dictated by the expected loading/desired water storage/sub base strength.
The amount of water which can pass through a permeable flagged pavement is dependent on the infiltration rates of the joint filing, laying course and permeable sub-base materials and not the proportion of open area in relation to the flagged surface.
SHW clause 805 4/40mm (crushed concrete) bound with 2/6 3mm crushed concrete aggregate to EN12620. Graded crushed concrete to EN12620 (re-cycled materials will add significantly to the overall sustainability of the project).
Structural Integrity
SuDSFLOW spacers are designed to act as a structural component of the paved area, by having a minimum compressive strength of 80 MPa and by providing the unique feature of a corner locking device. By using SuDSFLOW at each joint in line with the system design, the spacer will lock the corner of the paving unit in place thereby preventing dislodgement.
Additionally, SuDSFLOW spacers can usually be used close to buildings, as they allow dispersal of infiltration similar to that of natural vegetation. So, the 5m guidance provided for by Building Regulations for soakaways (which provides for a single point discharge) need not apply.