Laying Pavers

INTRODUCTION Concrete paving around the home can be completed in many instances by the home owner. If careful preparation and laying of the concrete pavers is done with the right equipment the owner can achieve a high quality job, The steps to follow do not contain all the details on pavement construction such as levels, drainage and other construction issues. If you are unfamiliar with these issues contact the Cement and Concrete Association of Australia for advice.
PLANNING Before you start any project around the home it is necessary to carefully plan the work. A plan of the area to be paved should be accurately drawn and marked out on site. Provision for stormwater run-off will be required along with the required services that need to run under the paved area along with the require services that need to run under the paved area such as stormwater and water pipes or pipework for a sprinkler system. If further works are required around the site such as retaining walls, check that access will still be available after the paving has been completed. It is important to determine the finished levels of paving when planning the project. The finished level of the paving must be a minimum of 25mm below the damp proof course of the house. If you intend to deviate from this minimum requirement you should consult an engineer for advice. PREPARING THE AREA Excavation It will generally be necessary to excavate the area to be paved. The depth of this excavation will depend upon the thickness of the paver plus the 30mm of bedding sand and 100mm of compacted roadbase material if required. Any loose or soft areas in the sub-grade should be removed and replaced with compacted material. Sub-Grade Correct base preparation is perhaps the most important part of the paving project. The sub-grade is the natural soil the pavement is supported on. This should be a firm solid base with the top soil and vegetation removed. String lines can be used to determine the finished level and area of paving. The finished sub-grade should be trimmed to within +0,-25mm of the design level and compacted if necessary. Backfill for service trenches should be compacted in layers to provide levels of similar strength and stiffness to the sub-grade. Roadbase The roadbase is imported compacted granular fill used to build up areas, set levels and provide a strong, stable layer to support the laid pavement. A 100mm thick compacted roadbase is required for all paving on clay sub-grades and all paved areas to have vehicle traffic. The finished level of the readable should be within +0, -10mm.
	The roadbase for walkways may be reduced on sandy or non-reactive sub-grades, however it does add considerable strength to the pavement and is recommended for a first class job. All roadbase material should be compacted with at least three passes of a mechanical vibrating plate compactor. Final Preparation The completed preparation for paving should be firm and level with a fall to allow for rainwater run-off. The use of string lines will help maintain the line and levels to ensure an accurate preparation. The prepared surface level should not deviate by more than 10mm over a 3m length from the required profile.
SCREEDING THE BASE A 30mm layer of washed concrete sand is required as the final preparation for laying the pavers, the levels of this base will be reflected in the finish of the paving so it must be accurate. The most effective method to level the bedding sand is to use the two screeding rails set accurately in the in the bedding sand to the required finished levels and placed approximately 1m to 3m apart. The screed board is then used to level off between the screeding rails. The rails are then removed ad the tracks filled with bedding sand and smoothed off with a trowel prior to laying the pavers. The bedding sand is not a leveling medium, the thickness must be kept consistent across the paved area to avoid uneven settlement of the paving to occur. Remember the level of the bedding sand will determine the finished levels of the paving so take your time to get it right, and allow for the necessary falls. LAYING YOUR PAVERS When laying the pavers it is generally best to start in a corner or along a straight edge such as the house footing. Place the pavers using the desired pattern on the screed sand leaving nominal 3mm gap between each paver. Take care to ensure that all pavers are level, by using string lines and regular visual checking of the paving it is possible to keep all the joints straight. Laid pavers can be adjusted with a screwdriver or trowel to correct any minor errors in the joint alignment.   Always work from on top of the pavers that have just been laid so as to avoid disturbing the screeded bedding sand. CUTTING PAVERS Leave cutting and placing of the edge pavers until the last step. Carefully mark the pavers to be cut and use a bolster and hammer. For a more professional finish hire a brick saw or brick guillotine to accurately cut the pavers. Remember to wear proper safety equipment when cutting pavers. EDGE RESTRAINT Where the paving does not abut a solid structure an edge restraint is required to prevent the pavers spreading or opening up. Finishing unsupported edges of the paving with a concealed concrete edge strip is the most common method used to support the pavement edge. The edge restraint should be kept at least 10m below the finished level of the paving to allow for compaction.   Alternatively the edge restraint can be an exposed concrete strip, a "solider" course of pavers with edge restraint or the edge pavers can be set on a concrete base. FILLING THE JOINTS Dry jointing sand should be spread over the surface of the pavers and swept into all joints in the paving. Compacting of the pavement should then be completed to lock the pavers in before brushing off the excess sweep sand. In some instances it may be necessary to make an additional pass over the paving with the broom and recompact the pavers to ensure all joints are thoroughly filled. COMPACTING THE PAVED AREA After the pavers have been laid and dry jointing sand spread over the surface and into the joints the pavers should be compacted. This will bed the pavers down and assist in ensuring all the pavers are level and any minor imperfections are rectified to produce a professional finish to the paving job. For small areas of paving a board and rubber mallet can obtain adequate results however for larger areas and a more professional finish it is better to hire a mechanical vibrating plate compactor fitted with a rubber or carpet base. A layer of dry sweep sand spread over the surface of the pavers will protect the pavers from damage during compaction. HELPFUL HINTS Paving around the home is well within the capabilities of a competent home owner - here are a few hints to help you ensure that you produce a first class job. When paving against the house it is recommended that the top of the paving is a minimum of 25mm below the damp proof course. It is also advisable to place a plastic membrane against the exposed concrete of the house footing. When lying the pavers onto the screeded bedding sand always work from on top of the laid pavers taking care not to disturb the bedding sand. When paving a slope it is important to start at the bottom and pave up the slope. If work is interrupted, sweep jointing sand into the gaps and compact the completed area to protect the pavement in case of wet weather. Concrete edge restraints are necessary to prevent pavers spreading and opening up. Pavers can be cut with a brick bolster and hammer. For a more professional a mechanical brick saw or brick guillotine can be hired. Do not leave wet sand lying on the surface of the pavers for any length of time as it may cause staining. Leave cutting of the edge pavers until the last job prior to compacting and jointing. Do not try to hose jointing sand into the joints, sweep it.

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