The sub-grade should be prepared to the engineer’s specification and the sub-base should normally be a well-compacted Type 1 to the designated thickness, taking into account traffic loadings and suitability of the subgrade.
Machine laying of clay pavers can offer an extremely fast installation process.
Penter clay pavers can be mechanically laid, providing complete accuracy and efficiency.
Once the installation process is complete, the pavers can be trafficked straight away and immediately demonstrate their ability to take the highest level of loading (T4) in line with BS EN 1344 2013.
Solid edge restraints should be used along the perimeter of all paved areas to restrict lateral movement (creep). Restraints should be adequate to prevent the escape of the bedding course material beneath the paver surface.
Cutting clay paving
Pavers should be cut using a multi-bladed mechanical paver splitter or bench mounted water-cooled power saw. Clay pavers should not be cut to less than a quarter of the original length and never cut width-ways.
Sufficient cross-fall should be provided to prevent standing water on all block paved surfaces.
Unpacking the pavers
To achieve the correct blend of colour, paver packs should be unpacked vertically and from a minimum of three packs. This will distribute minor size variations of the pavers over the entire pavement. Damaged pavers should not be used for anything other than infilling.
Sand bedding course and paving
Sand bedding course material should be washed in naturally occurring silica sand, selected in accordance with the recommendations given in BS7533: Part 3: 2005 and laid to 25-40mm compacted thickness over the thickness of sub base.
Bedding sand - unbound construction
Bedding sand provides the bed for which the pavers are placed on and accomodates any variation in paving thickness to ensure the finished surface course is even.
The use of a geotextile below bedding course to prevent migration of sand may be advisable if the sub-base is open textured.
Bedding mortar - bound construction
Pavers on a bound construction transfer vertical load through direct bearing.
The bedding mortar is spread out over the required area to the required depth (approx. 35-50mm thick).
Pavers should be laid in the designated bond pattern working from an edge restraint or existing laying face edge. Mechanical force should not be used to bring pavers into intimate contact.
Laying clay pavers
Where the pavement is to be laid unbound (flexible) paver units should be laid so that a 2 to 5mm joint forms between each paver, with a target joint width of 3mm to ensure there is no point contact between units.
Where the pavement is to be laid bound (rigid) should be laid with a 6 to 10mm joint. To promote adhesion it is advantageous to prime the underside of the clay pavers peior to settling on a bedding mortar.
The laying of any clay paver, with or without nibs, will require the opening or closing up of joints to maintain good lines throughout the work due to the tolerances of a natural clay product.
Compaction of pavers - unbound construction
The pavers are compacted onto the sand bed using a vibrating plate compactor with a rubber soleplate to avoid damage to the surface.
When a sufficient area of pavers has been laid - and before starting the vibration - a fine kiln dried silica jointing sand must be brushed into the joints (unbound construction).
After compaction, any damaged pavers must be immediately replaced, while any unevenness or differences in height must be re-adjusted.
Joint-filling - unbound construction
After compaction, a further application of fine kiln dried silica sand must be brushed into the joints until all joints are full.
Failure to ensure all joints are full before opening up the area to traffic may cause movement and loosening of the paved surface. Upon completion, traffic may be permitted to use the pavement. However, avoid using high-powered suction cleaners on newly laid areas.
Joint filing - bound construction
Mortar for jointing can be trowel applied or using a slurry mix. It is essential not to allow excess mortar/slurry to cause staining.
Movement joints for bound construction need careful design and consideration.
Wienerberger clay pavers are resistant to chemicals and cleaning fluids. Pavements using clay pavers can be cleaned using biodegradable detergents. Mechanical or high water pressure cleansing operations will require re-sanding between the joints.