The right approach
It is important to ensure sanded joints remain completely full and following completion of the construction process it is imperative not to carry out any cleaning of the surface which may remove the jointing sand.
It is beneficial to allow the jointing sand a period of at least 6-8 weeks to allow general dirt and detritus to naturally seal the sand in the joints. High pressure jet washing will remove the jointing sand 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.
Removal of moss/algae
To maintain a pristine appearance, particularly in north facing sheltered areas receiving little or no natural sunlight, algae may appear in the sand joints and on the paver surface. This can easily be removed with an application of an algae inhibitor, such as Agrigem’s Sapphire – 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 or free draining garden beds. Clay Paving laid with insufficient falls may retain moisture and detritus encouraging algae to grow. 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 where surface dirt is present, 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 the algal treatment with the chosen sealant.
It is possible, usually after a lengthy period of the clay paving being saturated, followed by warmer and drier weather that the surface of the pavers may exhibit a white powdery substance known as efflorescence. This is caused by the accumulation of soluble salt crystals on the surface of the pavers and is harmless. These soluble salts, often originating from within the bedding sand or jointing sand, travel through the paver in solution form and then 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 and plenty of clean water which will lift 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 form to be re-absorbed by the pavers and jointing material. The Efflorescence will then re-appear 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 causing a more permanent discolouration.
Should you require any further guidance please contact Technical Support at Chelmer Valley Brick Company Ltd.
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