Good cleaning practice will preserve the overall appearance of our hard landscaping and building products. The guidelines below, while quite comprehensive, are not exhaustive.
Some of the cleaning methods described may involve the use of cleaning materials which must be used correctly and strictly in accordance with suppliers’ / manufacturers’ recommendations.
The following precautions should also be noted:
It is particularly important with all cleaning methods that a trial should be carried out on a small, inconspicuous area, to determine the effect of the treatment before commencing work on a larger area.
The use of a stiff brush is recommended for several of the operations described below. Always use a brush with either natural or nylon bristles. Never, under any circumstances, use a wire bristled brush and avoid any process that detrimentally affects the surface structure and colour of the facing bricks.
Care should always be taken to avoid any excessive localised scrubbing.
Construction blemishes ie. mortar stains and smears, mortar droppings and water marks.
Prevention of any of the above is ultimately preferable to trying to carry out remedial cleaning. Good standards of work supervision and workmanship are needed to achieve the full benefit of a fair-faced, self-coloured brick-work finish. Mortar stains and smears can be carefully removed with an appropriate cleaning product. Products of this type must be used strictly in accordance with the manufacturer’s instructions and washed down thoroughly afterwards with water from a low pressure hose.
Oil penetrates readily into concrete, staining will be significantly reduced if any spillage is removed promptly with an absorbent material e.g. paper towels or cloth. Do not wipe as this will drive the oil into the concrete and spread the contamination over a larger area. If the stain persists, a cleaner suitable for the purpose should be used in accordance with the manufacturers’ instructions.
Alternatively, the surface can be scrubbed with a strong detergent and the residue washed away with hot water. However, care must be taken as this method might also result in the leaching out of some pigment from the concrete product and discolouration due to surface abrasion of the concrete.
Graffiti and paint stains:
Both paint and graffiti are difficult to remove. Fresh wet paint should be soaked up with an absorbent material without wiping the paint, as this will spread the stain. It should then be treated with a solvent suitable, for the paint involved, and the area washed with a concentrated detergent, taking care with the disposal of the run-off material.
NB. Most paint strippers are sulphuric acid-based and attack the concrete.
Dried paint should be scraped off as far as possible without damaging the surface of the concrete and an appropriate paint remover applied, used in accordance with the manufacturer’s instructions. Paint manufacturers may be able to give more detailed advice on the removal of graffiti and it may be necessary to consult them if there are large areas of vandalism.
General dirt, grime and scuff marks from sports footwear, balls and other rubberised equipment:
These can normally be removed by using a stiff brush, mild detergent and water from a low pressure hose. In stubborn cases steam cleaning or brushing the area with a stiff brush, hot water and a detergent can be employed – but a small inconspicuous area should be tested first.
In sports halls, AG would advise a policy that prevents the wearing of outdoor footwear. Furthermore, only sports footwear, balls and other rubberised sports equipment that doesn’t leave black / dark scuff marks on floors and wall surfaces should be used in indoor sports environments. This goes a very long way to reducing the need for aggressive cleaning methods on a regular basis.
These can normally be removed using a stiff brush with hot soapy water. Generally, avoid using bleach. However, if the stain is persistent a mild bleach solution can be employed and then rinsed immediately with clean water, taking care to dispose of the run-off safely. Again, testing on a small conspicuous area should be carried out first.
Paving and flagstones should be regularly brushed with a stiff non-metal brush to prevent a build-up of dirt. We also advise a more substantial clean two or three times a year, especially during spring and autumn.
Newly completed areas of paving or flagstones should only receive a light brushing in the first few months to allow joints to settle naturally. From then on, general maintenance should be carried out regularly.
Jointing material may be lost during the early life of the pavement in both dry and wet weather, being blown away in dry conditions or washed away from the surface during heavy rain. It is therefore important to inspect areas of new paving regularly in their early life and top up joints where needed.
To remove general dirt, a cyclic maintenance regime should be considered based on expected traffic and use. If detritus dulls the colour of the paving, it can be re-established by mild controlled pressure washing or scrubbing with proprietary solutions following the manufacturer’s guidelines. This can be carried out by hand or by using industrial cleaning equipment. Using a bristle brush with mild detergent and hot water is normally all you need to remove any build-up of dirt and grime.
Mechanical sweepers or scrubber drier machines can be used to assist cleaning regimes long term however, it is advisable to avoid this cleaning process in the early life of the pavement to allow detritus to have sealed the joints.
Moss, lichen and algae may grow on paving in areas which are heavily shaded or under trees or are not laid to an adequate fall, leading either to slow running off or ponding of surface water. If such growths do occur, the areas should be treated with an appropriate proprietary weed killer, used in accordance with the manufacturer’s instructions.
If rust stains occur on the paving, the first requirement is to eliminate the source of the staining. To remove rust stains, the surface should be wetted and the affected area treated with a prop solution. After cleaning, the paving should be well washed down to remove all traces of the acid. It is common to find that rust stains can be sourced to the spreading of weed killer on green areas close to the paving. The chemicals in the weed-killer react with the pigments in the paving and rust coloured stains result. If there are locations where green areas and paving meet then consider using a block paving which has low pigment content.
Most stains associated with everyday life such as mineral / alcohol and food can be removed easily. These can normally be removed by scrubbing with a strong detergent and hot water solution. If the stain is persistent, apply a bleach solution and then rinse the area well with clean water.
Chewing gum is difficult to remove from all paving surfaces. Newly discarded gum can be scraped off using a scraper, but hardened gum can only be removed by freezing / heating or chiselling it from the surface of the paving, or by using a high pressure water jet. If persistent then consideration should be given to a quality sealant to put a protective coating on the paving.
Scuff marks are common in locations where vehicles are used. These can normally be removed by mild power washing / steam cleaning, or by scrubbing the area with a strong detergent and hot water solution.
Oil does not penetrate readily into the body of paving, but if oil is spilt on the paving the spillage should be removed promptly with an absorbent material. After soaking up the majority of small spills, prompt washing with a prop solution should remove the stain.
The best method of removal is to leave the bitumen until it has cooled and remove it with a paint scraper or similar mechanical device. If it is particularly resistant, the use of ice to make the bitumen even more brittle may be required prior to scraping it from the paving. Any residue should be removed with an abrasive powder and finally the whole area rinsed with clean water.
Both paint and graffiti are difficult to remove. Wet paint should be soaked up with an absorbent material. The area should not be wiped, as this will spread the paint. The spillage should then be treated with a suitable solvent, such as white spirit and the area washed with a strong detergent and hot water solution. Steam cleaning can also be employed. When paint has dried, it should be scraped off as far as possible and an appropriate paint stripper applied. This should be used in accordance with the manufacturer’s instructions.
Once the paint has been removed by the chemical, the area again should be washed with a strong detergent and hot water solution. Paint manufacturers may often be able to give more detailed advice on the removal of their own products. There are companies specialising in the removal of graffiti and it may be necessary to consult them if there are large areas affected by the accident or as a result of vandalism.
Solidified epoxy or polyester resin can be removed by carefully burning the spillage with a blow torch or other heat source. Care must be taken not to inhale the fumes given off during the process. If after burning, a black stain remains on the paving, this can normally be removed by scrubbing the paving with a strong detergent and hot water solution. A small area should be tested before any large scale cleaning is undertaken.
Normally these stains can be removed by scrubbing with a strong detergent and hot water solution. Where the stains persist, a mixture of scouring powder and household bleach can be used, but this should only be used in very well ventilated areas. When using bleach, it is important that the affected area is thoroughly washed once cleaning is completed.
All paved areas may be treated with de-icing materials. Normal de-icing salts can be applied without any risk of damage to the pavement. Once the pavement has dried out after any thaw, however, the paving may be temporarily discoloured by the de-icing salts, as is the case for any other surfacing material. This may or may not happen depending on the product and paving however normal weathering should soon remove such discolouration after a short period.
Currently there are various high quality and effective sealant products available from local merchants and specialist companies. These can be either impregnators or sealants to help with stain removal or to provide some benefit in stabilising the sand in the joints in the short and longer term. If a surface sealant is used on paving, it must be applied in strict accordance with the manufacturer’s instructions. Sealants may affect the colour of the pavement and its slip / skid resistance and may require ongoing maintenance during the life of the paving. AG recommend the use, where possible, of sealants which have proven organic materials and less chemical properties.
Where new services are to be installed or access is required to existing services under the paved area, the paving should be lifted carefully, cleaned and stockpiled for later use. Once the initial paving has been removed, it should be relatively straightforward to uplift the area of paving. During re-laying a slight surcharge should be created in the sand bedding course to allow for settlement of the paving following initial compaction and early trafficking. Typically, reinstated areas of paving should have a surcharge of 2-3mm over the surrounding paved area.
Clean using a stiff brush, mild detergent and hot water rinsing with a low pressure hose.
As with any type of remedial work, this should be tested on a small area which is not easily seen (in accordance with the manufacturers instructions), so that it can be assessed before carrying out work on a large area.
Remedial cleaning procedures may affect the final appearance of the masonry. For your safety, make sure you use appropriate PPE.
Using a power hose is not recommended as it may damage the surface of the product and encourages algae vegetation growth.
It’s best to take preventative measures if graffiti is likely to occur. Anti-graffiti systems are available. These consist of a protective sacrificial coating on the masonry which acts as a barrier against the adhesion of the graffiti.
This should be treated with an appropriate proprietary weed killer applied with a low pressure sprayer, used in accordance with the manufacturer’s instructions.