Dutch Clay Paver Maintenance Guide for Commercial Applications
Generally, clay paving requires minimal maintenance providing the paving has been laid in accordance with “BS 7533 – Pavements constructed with clay, natural stone or concrete pavers”, the Code of Practice for laying precast concrete paving blocks and clay pavers for flexible pavements.
Resistance to staining
One of the advantages of clay paving is its ability to resist discoloration from dirt/oil/fats etc., having a relatively low water absorption and high durability preventing stains penetrating and becoming ingrained into the surface. Oil/diesel etc. tend to lay on the surface of clay pavers and are dispersed naturally. Any stubborn build up can be removed by off the shelf de-greasers followed by rinsing down with clean water.
It is important to ensure sanded joints remain completely full and following completion of the construction process it is imperative not to carry out suction street cleaning for at least 6-8 weeks which will allow general dirt and detritus to naturally seal the sand in the joints. Should there be a high incidence of street cleaning required, for instance outside fast food outlets where the use of high pressure water jetting or mechanical sweeping is used, this will remove sand between joints and may weaken the integrity of the surface. If joints between pavers are void of sand these must be re-sanded using fine dried silica sand.
In any situation where a flexible/unbound construction method is used, whereupon jointing sand may be regularly removed by pressure washing or scouring, it may be beneficial to apply a joint stabiliser/paver sealant which will prevent jointing sand erosion. RESIBLOCK ‘22’ is a specialist jointing sand stabiliser designed for heavy duty small element flexibly laid clay paving www.resiblock.com/product/resiblock-22 , or similar approved. Please be aware that some general sealants may alter the colour of any surface they are applied to and as such we would strongly recommend a trial area is determined.
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Removal of moss/algae
To maintain a pristine appearance, particularly in north facing sheltered areas receiving little or no natural sunlight which may be overhung with trees or vegetation and very little footfall, algae may appear in the sand joints and paver surface. This can easily be removed by the cleansing operation described above followed by an application of an algae inhibitor, such as Agrigem’s Sapphire – https://www.agrigem.co.uk/sapphire-moss-killer-5l or similar approved. Please contact the supplier for further information regarding application guidelines.
To prevent the establishment of algae please ensure paved areas are laid to falls directing surface water into a drainage channel. Areas laid flat or have insufficient cross fall may retain moisture and detritus encouraging algae to gain hold and staining from dirt. In areas with a low footfall preventing the natural dispersion of dirt from the paving surface, it may be necessary to sweep these areas more regularly.
In specific problem areas retaining surface dirt, consequently promoting algal/moss growth, it may be beneficial following the cleaning and algal treatment to stabilise the joints and seal the surface. This will further inhibit algal growth and make subsequent cleaning easier. However, please check the compatibility of whichever algal treatment is used with the sealant.
Should any graffiti or accidental damage be caused by spilt paint etc., lifting of existing pavers and turning them over followed by recompaction and sanding of the joints should fix this problem.
It is possible, usually preceding a lengthy period of the clay paving being saturated, such as a long wet Winter followed by a warmer and drier Spring, the surface of the pavers may exhibit a white powdery substance known as efflorescence. This is simply the accumulation of soluble salt crystals on the surface of the pavers and is totally harmless. These soluble salts, often originating from within the bedding sand or jointing sand, travel through the paver in solution and crystalize upon the surface. This temporary accumulation of salts on the paver surface will naturally blow away or can be swept away using a soft bristle brush. However, should this brief appearance be unsightly then the crystals may be dabbed off using a moist sponge using plenty of clean water which lifts the crystals off the surface. Totally saturating the affected area with a hosepipe may appear to have removed the salts, but this saturation simply dissolves the soluble salts back in to solution only to be re-absorbed by the pavers and jointing material to re-appear once again as the surface dries out. Under no circumstances apply brick cleaning solutions, such as diluted acids, as this may cause a chemical reaction subsequently ‘fixing’ the salts on the surface and possibly cause a more permanent discolouration.
Should you require any further guidance please contact Technical Support at Chelmer Valley Brick Company Ltd. Tel. 01277 219 634 or email firstname.lastname@example.org