Cleaning Pavers and bricks

Cleaning pavers and bricks guidlines

Tyre Marks

Pavers – Remove tyre marks with degreaser 612 or Graffiti remover.
Method : Place some degreaser in small container. Using a stiff bristle scrubbing brush apply degreaser to area and scrub of marks.
When finished wash down area.

Organic Growth

Removing organic growth from pavers with moss, algae or slimes growing on them.
Moss, algae and slime all need some of the following environments to be present in order to grow.
They require moisture, poor drainage, a stable environment base and nutrients. Unfortunately this is the case of many peoples gardens.

The following guide is designed to assist you with minimising the reoccurrence of the problem.

Stage 1

1. On a sunny day, follow the following steps.
2. Hose down pavers so that they are wet.
3. Saturate any surrounding garden or lawn.
4. Using a stiff broom, apply a 10: 1 solution of water and sodium hydrochloride (liquid pool chlorine) to the effected area. Scrub pavers well.
5. Once all affected pavers have been covered and scrubbed, leave for approximately 20 minutes.
6. Re saturate garden again and then hose any residue off pavers.
7. For any missed areas, repeat steps 2, 3 & 4.
It is important to note that this must be done on a sunny day as the sunlight breaks down the chlorine.

Stage 2

To help with this problem from reoccurring, follow the following steps in the last few warm weeks of summer

1. Saturate any surrounding garden or lawn.
2. Apply 15 milligrams of copper sulphate to 1 litre of water to the pavers while the pavers are dry.
3. Leave on pavers for approximately 1 hour.
4. Saturate any surrounding garden or lawn.
5. Hose away any residue.

Sealing Pavers

1. Wet area thoroughly
2. Mix Hydrochloric acid and water ratio;15.1
3. Wash area with stiff broom and hose off after 5 minutes
4. Ensure pavers are clean and completely dry before sealing and that no rain is forecast for 24 hours.
5. Apply paving sealer to area with either light broom or roller. Be sure to check the instructions and follow all safety directions.

Sealer supplier: Decorative Technologies Ph 8359 5770

Brick Cleaning and Maintenance

The Littlehampton Brick Company recommends the services of a professional cleaner if a stain is too big or difficult to remove. If you are in any doubt, please contact us on 8391 1855.

The appearance of a brick building can be permanently spoilt by bad cleaning techniques or by the use of the wrong cleaning agent. For this reason, it is important to ensure that the correct cleaning methods are utilised for the best results and to help reduce the associated problems with brick cleaning.

It is good practice to test the method on a small inconspicuous area, to determine the effectiveness of the cleaning compound and the technique, and to check the wall for possible damage.

Safety Precautions

The chemicals used during cleaning are highly corrosive (some are classified as S6 poisons). The manufacturer’s instructions and safety precautions should always be followed when using acids and other proprietary cleaning chemicals.

The few points below should be followed to avoid serious personal injury:

Always wear protective clothing and protective equipment such as gloves, safety glasses, etc.
Do NOT use high pressure cleaners to apply cleaning chemicals as it is dangerous to the operator and to those nearby.
Store acid and acid solution in heavy duty plastic containers supplied by the manufacture and ensure that the containers are correctly stored (eg away from children).
If the cleaning solution comes in contact with the body, irrigate the area with water immediately to remove all traces of the cleaning solution. If irritation continues seek medical advice immediately.

Cleaning Mortar Stains with Hydrochloric Acid

Hydrochloric acid is mainly used to remove mortar stains from clay brickwork.

Generally, hydrochloric acid should not be used to treat any other stains or at any other time during the life of your brickwork. If used incorrectly, it can cause unsightly staining that is more difficult to remove. In particular, care should be taken to treat any vanadium stains prior to cleaning with hydrochloric acid.

It is very important that protective clothing be worn and that the safety and chemical storage precautions necessary for working with hydrochloric acid are followed. The following procedure is recommended when cleaning with hydrochloric acid:

1. All mortar dags should be removed using either a metal or wooden scraper.
2. Protect all areas which may come in contact with the cleaning agent as recommended by the manufacturer.
3. Saturate the area of brickwork to be cleaned and all adjacent areas below with water.
4. Use the correct ratio of hydrochloric acid and water:o Light coloured bricks – 1 part hydrochloric acid to 20 parts water o Dark coloured bricks – 1 part hydrochloric acid to 10 parts water o Under no circumstances should more than 1 part hydrochloric acid to 10 parts water be used. It is better to scrub more vigorously than to use more acid.
5. When cleaning, try not to work in direct sunlight.
6. Always begin at the highest point and work down the wall.
7. Only clean small areas at a time, for example one square metre, so as to allow adequate time to wash off the cleaning solution, to ensure no staining occurs.
8. Allow solution to remain on wall for 3-6 minutes before scrubbing. Be sure not to scrub the joints.
9. Rinse thoroughly, making sure all cleaning solution has been removed.
Note: light coloured bricks should be rinsed with a neutralising solution, such as bicarbonate soda or washing soda, instead of water.

PLEASE NOTE: This method is NOT to be used on Old Red Sandstock or Tuscany Bricks.
For cleaning information on these bricks please contact us on 8391 1855.

Hand Cleaning

Hand cleaning is appropriate for small jobs or for when the use of a high pressure water jet is likely to cause damage.

The following procedure should be followed:

1. Allow mortar to harden (clean 24-36 hours after completion of masonry work) and remove any large mortar particles with hand tools
2. Protect adjacent materials as recommended by product manufacturer
3. Saturate the wall with clean water. Never let the wall dry out during cleaning; work on small areas
4. Test a small unseen section prior to full-scale cleaning
5. Apply the acid solution (as described previously) to the wall using a brush or spray
6. Allow solution to remain on wall for 3-6 minutes before scrubbing vigorously
7. Rinse thoroughly as small areas are cleaned

High Pressure Water Jet Cleaning

High pressure water jet cleaning can be used on clay masonry, but precautions must be taken so that the bricks and the mortar joints are not damaged by the process.

The following procedure should be followed:

1. Allow to mortar to harden (must be older than 3 days) and remove any large mortar dags with appropriate hand tools
2. Protect adjacent materials as recommended by product manufacturer
3. Saturate the wall with clean water. Never let the wall dry out during cleaning; work on small areas.
4. Test a small unseen section prior to full-scale cleaning
5. Apply acid solution (as described previously) by hand. Applying chemicals with high pressure cleaners is dangerous and is NOT recommended for safe and successful cleaning.
6. Wash the wall with high-pressure water after allowing the solution to remain on the wall for 3-6 minutes.

When operating the equipment ensure to:

  • Keep pressure low – maximum 7000kPa (approximately 1000psi)
  • Use a wide fan spray nozzle (15°)
  • Operate the nozzle at generally 500mm from the wall or never closer than 300mm
  • Use ‘runs’ of approximately 1m in width and double clean to ensure the best clean
  • Keep the gun moving constantly or surface abrasion in one spot will result

Warning: If the mortar joints or the bricks are being damaged, either the pressure is too high or the water jet is too close to the wall. It is strongly recommended that a test area should be used to check the impact of the high pressure cleaning on the bricks and mortar.

High pressure cleaning is NOT recommended for dry press bricks and increased care should be taken with slurry coated bricks.

Cleaning Internal Brickwork

Extra care should be taken when using hydrochloric acid to clean mortar stains on internal masonry.

Acid fumes produced during cleaning should be ventilated adequately.

The likelihood that the acid fumes will persist into the period of occupation can be reduced by:

Cleaning the internal masonry early in the construction period, thereby allowing the walls to be rinsed sufficiently
Using an acid inhibitor to reduce fumes or applying a neutralising solution to the wall

Efflorescence

Efflorescence is a powdery deposit of salts which forms on the surface of bricks and mortar. It is usually white but efflorescence can be yellow, green or brown.

A temporary efflorescence is particularly common on new brickwork as soluble salts are transported to the surface of the brickwork by water. The picture below shows efflorescence on brickwork.

Efflorescence can occur from a variety of sources. New bricks contain minimal, if any, soluble salts, but mortar and concrete have relatively high soluble salt contents. Ground waters that are naturally salt-bearing can be drawn into base brickwork. A faulty or bridged damp-proof course will allow the salts to migrate up the wall.

Render that has been applied over a damp-proof course can also allow salt to migrate up the face of the brickwork.

Water allowed to enter uncovered cavity walls during construction is also likely to cause efflorescence, so brickwork must be protected from water entry during construction.

The amount of efflorescence that occurs is directly related to the amount of water in the bricks, and their drying time. The more water in the bricks, and the longer it is there, the more chance salts will have to dissolve and be brought to the surface as the bricks dry out.

Efflorescence on new brickwork may be unsightly, but it will not cause damage unless it persists for a long time.

Persistent efflorescence should be taken as a warning that water is entering the wall through faulty copings, damp-proof courses or pipes. If allowed to continue unchecked, the salts carried to the face of the wall may eventually attack the bricks and cause deterioration).

Remedy

Laying dry bricks and providing good ventilation to speed up the drying process after the bricks have been laid can minimise efflorescence.

Forced ventilation and heating of the premises may be necessary to ensure drying during cold winter months.

The best removal method is simply to brush off the deposit with a stiff dry bristle brush after the wall has dried out.

Collect the removed salts with a dust pan or a vacuum cleaner to prevent the salts re-entering the brickwork.

Wetting the wall by methods such as hosing usually dissolves efflorescence back into the brickwork, allowing it to reappear again when the wall dries out.

Acid or alkaline treatments are not recommended as they do more harm than good because they add to the total salt content of the wall.

The application of kerosene or oil does little or nothing to hide the efflorescent salts and prevents their subsequent removal by brushing and washing.