Sub-grade
Excavate to sub-grade appropriate levels shown on site drawings to provide a minimum fall of 1:1000 to fin drain. The sub grade should be compacted with a vibrating plate. Prior to compaction all soft areas should be removed and filled with suitable replacement material to provide a stable sub-grade.
Kerbs/edgings
The paved areas must be firmly restrained. The kerb edging must extend with sufficient height above the haunching to accommodate the full laying course depth and block height.
SC Membrane® Geosynthetic
The SC Membrane Geosynthetic must be water tight therefore a taped joint may be insufficient. To ensure the integrity of the membrane the joints should be fully welded, this can be completed on site or pre-formed off site and delivered ready for installation.
Sub-base
The lower layer of subbase (10-63mm) should be placed in 2 separate layers, each layer being compacted with a vibrating plate.
SC Intergrid® Geogrid
Where required the Intergrid should be incorporated at the interface between the two layers of sub-base. The Intergrid should be laid on the sub-base and joints should be overlapped by 300mm.
The upper sub-base layer (5-20mm) should then be laid on top of the SC Intergrid Geogrid and compacted as before.
Inbitex® Geotextile
Lay geotextile on top of the sub-base overlapping joints by 300mm. Inbitex Geotextile should be brought up to the haunched kerb/edging and cut-off flush with the surface of the paving.
Laying course
Lay and screed to level approximately 50mm depth of 2-6mm single sized crushed stone to BS EN 13242: 2002. It is important that the final level of the 2-6mm stone is accurate as the stone will compact down much less than sand when the surface blocks are vibrated. The particle shape of the 2-6mm stone will also affect the degree of compaction. It is recommended that a small trial area should be laid prior to construction to determine the accuracy of final levels.
Block laying
It is advisable to pre-set the block level by 6mm to allow for the effects of settlement when laid against fixed edgings. The blocks and slabs must be tightly butt jointed ensuring that a good fit is achieved. A single or double stretcher course of Aquaflow blocks must be used around the periphery of the paved areas and also at the edges of any separately restrained areas, such as tree pits. Where blocks need cutting, they should be cut to a tight fit and none are to be smaller than 30% of the unit block size. Blocks should be cut vertically and not underscored. All block cutting should be carried out with a disc cutter.
Surface finish
The blocks should be vibrated with a vibrating plate. Following the first pass with a vibrating plate, the tapers and slots should be totally filled with 2-4mm clean quartzite. (Available from Formpave in 25 kg bags). Blocks should again be vibrated and any debris brushed off.
Pump Chamber (Sump)
The sump is connected to the Aquaflow system at the fin drain.
Excavation
A hole is dug to the dimensions of the pump chamber. This is lined with an impermeable membrane, it can be taped using double sided tape but for total integrity it is recommended that a welded membrane is used. The pump chamber is then placed within the membrane. The pump is inserted and connected to the mains. The chamber is then wrapped in the membrane and covered with soil. The soil is compacted to make a firm surface.
The laying course should be 50mm of 2-6mm clean crushed stone. All granular sub base must comprise Crushed gravel or rock possessing well defined edges. The 100mm deep upper layer of sub-base material should be graded 5-20mm to BS EN 13242: 2002.