Engineering Specifications
- Tasman Retaining Walls (1.1MB PDF).
- Norfolk Retaining Walls (219KB PDF).
- Curing vs Ageing (12KB PDF).
How to Install Your Pavers
The correct laying of pavers is vitally important to the overall look of your investment. Your paving should not only enhance the value and look of your property but be practical and long lasting. To ensure that the paving is correctly laid, there are several steps to be considered which are outlined below.
PREPARATION WORK: It is critical to the long lasting stability of your paving project that the foundation for your pavers be constructed property. Essentially there four factors that have to be considered:
- Drainage
- Sub-grade
- Base-course
- Bedding Course
-
DRAINAGE: The objective of good drainage is to prevent the accumulation of sub-surface water anywhere underneath the paved area. Sub-surface ponding may reduce the stability of the whole paved area or bring efflorescing salts to the paving surface and thus detract from the appearance and durability of the paving.
To create good drainage the sub-grade or excavated surface has to have a slope so that any moisture will drain to the low point. At the low point a drain should be installed to allow the moisture to run away from the paved area. Ideally this should be plumbed into the storm water drain.
SUB GRADE: The sub-grade is the upper part of the soil, natural or constructed, which supports the loads transmitted by the overlying paving. The sub-grade should be well drained and compact prior to laying the base-course.
BASE COURSE: The base-course is the foundation for the pavers and will vary in thickness depending upon the type of sub grade and whether the paved area is for a footpath or driveway. This thickness will vary between 50 mm and 120 mm. In exceptional circumstances, footpath pavers can be laid without a base-course where the sub-grade material is compact and uniform. We recommend quarry rubble as a base-course material which should be compacted at optimum water content. The compacted surface should be tight or close knot to prevent migration downwards of the bedding course material.
BEDDING COURSE: Sand is used as a bedding course material. The sand must be a well graded course sand (washed river sand) or quartzite sand. DO NOT use fatty sands or loams as they are difficult to consolidated and do not form a capillary break. Crusher dust is also unsuitable as a bedding course.
The sand should be between 25 mm and 35 mm thick and carefully screeded (levelled) with a straight edged stick prior to placement of the pavers.
LAYING THE PAVERS: Setting out: The best way to ensure your paving pattern stays in line is to use set out lines (a grid of string lines spaced at exact intervals around the perimeter of the job.) When setting our your grid remember to add 2-3 mm to each paver width to allow for the gap between each unit.
EDGE RESTRAINTS: It is vital to restrain the edges of the laid paving to prevent wash out and fretting of the bedding sand at the edges of your newly paved area. (This can cause subsidence of the edge pavers.) Edge restraints are many and varied and can be mortar, reinforced concrete, kerbing, paver on edge placed in wet concrete, etc.) Your paving consultant can advise on methods of edge restraints.
JOINT FILLING: The bedding course sand can be used as a joint filler which is the easiest and cheapest option. Sand however can be washed out or removed by ants. Commercial products can be used such as 'Supersand' which prevent washout.
Consider adding 4% by volume of cement to the sweep sand or joint filler which will solve the problem of ants and possible weed growth between the joints. Cement can also be added to the bedding course material if required.
COMPACTING THE PAVERS: Compact the pavers using a mechanical plate compactor with a piece of carpet or rubber mat under the compactor to prevent the pavers from being scratched or damaged. After the first pass of the compactor, sweep in more jointing sand and compact again before sweeping off excess sand.
SALT STAINING: All paving materials contain salts, magnesium and calcium which can cause staining. Some sub-grades and base-course materials also contain a high proportion of salts. Staining can be caused by the migration of salts by capillary action to the paving surface. If the drainage provisions and bedding specification above are adhered to, the risk of efflorescence or salt damage is minimised.
SELECTING A CONTRACTOR: If you feel that laying your paving is not for you, then experienced contractors are available to complete your work. It is recommended that you use only an accredited paviour. We recommend you obtain 3 quotes, itemising the exact work quoted for. Inspect previous work and contact other customers, if possible, to ensure the contractor is capable of providing the finish you require.
To achieve the best results from your pavers it is recommended that your pavement be designed by a suitable qualified engineer and installed by an accredited paviour.
When paving against a house it is recommended that the top of the paving is a minimum of 70mm below the damp proof course and 50mm with the use of Termimesh. It is also advisable to place a plastic membrane against the exposed concrete of the house foundation.
If you require further information or assistance, please do not hesitate to contact us on (08) 8250 4422, as one of our paving consultants will be very happy to help you.