BS 7533-9:2010 pdf download – Pavements constructed with clay, natural stone or concrete pavers – Part 9: Code of practice for the construction of rigid pavements of clay pavers
5.3 Preparation of bedding mortar The bedding mortar should be uniform in thickness and should not be used to overcome variations in levels of underlying construction or to achieve falls. Only sufficient bedding mortar should be prepared and laid to enable the laying operation to be completed within reasonable time, this being determined by the mortar which should not be used when more than 2 hours old.
5.4 Stiff plastic mortar bed Bedding material usually comprises a layer of M12 mortar which should be of a stiff plastic consistency, with the joints pointed or formed to a desired profile as work proceeds. The mortar layer should be a minimum of 20 mm thick after compaction. NOTE Reference is sometimes made to a grouting or tiling method of laying, whereby joints are filled using a cement-rich grout or a strong pointing mix [1:3 cement-sand (proportions by volume)] as a separate operation some 12 hours or more after bedding. Experience has shown, however, that unless the contractor is very experienced in the technique, an unsatisfactory messy or stained finish might result, particularlywith rougher-textured pavers.
6 Installation of paver surfaces
6.1 General Due to the variety of clay pavers available and their ranging physical characteristics, reference should be made either to previous applications or to the manufacturer before a paver is chosen for a particular application (see Annex A). Details of the laying pattern should be specified before laying begins. A reference panel with a minimum size of 1 m 2 , should be used for establishing the visual acceptability of materials and workmanship maintained during paving construction work.
6.2 Bonding and laying patterns
6.2.1 Pavers should be laid on their bed face (i.e. the largest face) or on their edge (i.e. the second largest face). The consequence of laying standard format pavers on the bed face is that the normal length to width ratio is 2:1, whereas when laid on edge the length to width proportion is 3:1; these proportions should be borne in mind when specifying a bond pattern. NOTE Pavers ofless than 65 mm thickness, when laid on edge, are not intended to bond with their length, but they may be used on edge for the margins ofpaved areas. Pavers ofany thickness can be laid in stretcher/running bond and stack bond patterns.
6.2.2 For economy, pavers should be laid on their bed faces because each square metre of paved surface requires 40 standard format pavers, but 60 pavers if they are laid on their edge faces; more mortar is also required to fill the additional number and depth of the joints. NOTE Pavers on their edge might have different slip or skid resistance values to those on their bed face.
6.2.3 Paver size suitability should be selected in accordance with Table A.1. NOTE There are four basic bond patterns shown in Figure A.1. Variation and mixture ofthese patterns gives a great varietyofchoice, and the inclusion ofborders and panels separating courses can lead to further enrichment ofthe surface. Not all paver shapes are suitable for all the patterns illustrated.
6.2.4 Normally, patterns are based on whole pavers, with cut pavers only being used to fit into edges and the non-regular abutments of paving to walls, etc., therefore sections smaller than half unit pavers should be avoided. Cuts should be made using a diamond-tipped water cooled saw to ensure sharp square arrises on pavers. NOTE The use ofhalfpavers allows many additional attractive bond patterns to be created in rigid laid pavers.
6.2.5 Within the same area, pavers should be laid either on edge or on bed face throughout. Pavers laid in a trafficked area should be laid in a herringbone pattern [see Figure A.1a)] to aid interlock. NOTE For edging, pavers may be laid on their edge, or on end (on their smallest face). This allows for a more substantial concrete haunching to be placed to restrain the edge ofthe paved area, unless an edge restraint is provided bysome vertical element, for example walling.