Preparation and laying of Pavers by Peter Moller, Lifestyle Landscaping Bundaberg.
The key to successfully using paving to enhance your landscape project is preparation. There is no way to get around this and any deficiencies in preparation will come back to bight you in the weeks and months ahead. Lets take this right from the start.
Excavation & set out of areas to be paved.
When you have set out the area to be paved you will need to establish the preferred finished levels of the area. Drainage must be taken into account to ensure water freely drains from the areas to avoid ponding and therefore saturation of the finished surface, and potential failure of the paved area. Where seepage is likely you may need to install a subsurface drainage coil to avoid potential failure of the subgrade. Where localised soft patches are identified you must dig out the soft area, then cement stabilise the area by dry mixing at a rate of 5:1 with roadbase material of crusherdust. Allow the moisture from the subgrade to moisten the mixture then supplement the mix with some additional water to a even and moist consistency. Throughly compact the area with a mechanical vibrating plate.
When determining the depth of excavation there are two main issues you need to bear in mind.
1/ what is the likely traffic for the paved area….pedestrian or vehicular or commercial traffic.
2/ identify the soil type you are working with, very plastic ie. clayey soil, medium loam soils, or sand soils. Of course there are variables in these categories.
In general terms you will find 50-75mm of Crusher Dust (cracker dust) or decomposed granite is suitable for most pedestrian area. In extreme conditions specialist advise may be necessary to provide a long term solution for your project.
Where vehicular traffic is likely 100 -150mm or compacted roadbase (cbr 60) is required to provide a solid foundation for the area. Always compact in layers no more than 100mm deep (loose lay) in any one time. To achieve the required compaction you must add water to provide an even mositure level. Compact the area, then wet down to avoid super saturating the area. Several passes with a vibrating plate is required and by choosing different angles across the area will assist in achieving the compaction needed for the stable base. Use a levelling bar on a Bobcat to provide you with a consistent depth of material, then recompact again taking care not to disturb the loose stones as you turn on each crossing. Now a 10-15mm layer of crusher dust is to be spread over the entire area and screeded to achieve the desired shape and falls on the paved surface. Recompact, then wet down lightly and rescreed. Forget this process and you will likely have slight inconsistencies in your finished surface. This layer fills all the voids in the roadbase and then allows an even bed of sand to be spread over the entire area. A 10mm sand bed(using medium bedding sand) is to be spread & compacted, then final screed the sand ready for laying.
Screeding in undulating surfaces is freehand with screeds of varying lengths from 450mm wood float to 2.4m aluminium screed. At times screed bars can be used to provide a consistent depth of sand.
Set Out..paved areas
Set out string lines in several ways…this is used in any square or 45 degree patterns… strings set out using the 3:4:5 layout gives you a sqaure line to start, then set out the next line at about 1-1.2m grids in both directions. Always loose lay pavers, never continually tap pavers up to meet the lines as when you find larger pavers and you will, your lines will be all over the place. There are so many tips and tricks to laying pavers we could talk for hours… rather than bore you to tears, call me and I’ll be happy to assist you with the best way to get a great result in your next paving project.
Marking & cutting pavers.
With all the pavers laid there will be all sorts of odd shapes that will need to be cut. Cutting is easy with a Brick saw, choosing the diamond blade to suit the product you are using. When you start marking, lay a paver as a header course along the edge after overlaying the last paver in the body of the paved area. Then either use a string line for straight lines or a 10mm PVC conduit for curved areas. Take the pavers away marking the waste piece on the pavers and carefully place the pavers into place as the header is also installed. This is the basics for cutting pavers, you may also need to mitre joints, taper pavers etc to make it all a great job. So call if you need some help with this as its critical to the appeal of any project.
Concrete Border for retain pavers..
In driveway you will need to dig 50mm under and down from the edge of the paver then pour a solid yet moist concrete nib to fill this void then extend out 100-120mm wide then tapered up to half way up the edge of the paver and carefully trowelled into place. In walking areas a simple 45 degree nib to 20mm below the under side of the paver will suffice.
Sand jointing of pavers.
Hey we are almost complete…obtain a fine dry sand, like salt is great. You will need about 1 wheelbarrow to 45m2 of paved area when using 230 x 115 pavers. Spread over the surface and broom to a consistent fullness so there is plenty of sand covering the pavers. Now attach a piece of carpet under the vibrating plate and vibrate the sand into the joints, whilst someone brooms in behind you to fill any joints not filled in the first pass… do this a few times and you are ready for a quick broom down and you are ready to use the area. GREAT JOB.
This is a summary of the key factors necessary to successfully lay pavers to your next paving project, that will look great for years to come. As I mentioned there are many more factors to solve the many issues that arise in professionally laying pavers, let me know if you need a hand to get started on yur next project…Call me on 4155 5500 in Bundaberg at the Lifestyle Landscaping Solutions. Or call us and we can look after the entire project from start to finish. Now we also lay pavers on a concrete base which we will cover in a coming blog.
written by Peter Moller