Maintaining bricks | Clay Brick Association of Southern Africa

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How can I remove paint on my brick wall?

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 suitable solvent, such as white spirit, and then the area washed with a de-greasing agent taking care in the disposal of the run-off material.

Brick is porous, so paint sinks into all the grooves on the surface. Chemical and gel masonry strippers are the solution for inside walls; and while the process of stripping the brick is not complicated, it involves multiple applications of stripper and lots of scrubbing, making it a time-consuming project. It is impossible to scrape like wood, and interior walls cannot easily be water- or sand-blasted.

Pressure washing should NEVER be used as it can quickly erode the surface of bricks. Some caustic chemical solutions can cause surface failures or can change the color of old bricks. Rapid deterioration is then likely to occur, resulting in the need for major repairs

With dried paint, the paint should be scraped off as far as possible and then a paint remover to BS3761 (4) should be applied.

Put on safety goggles, a face mask and work gloves to avoid...

How do I remove moss & algae from bricks & paving?

It is common to find growths such as algae, lichens, liverworts and moss growing on hard surfaces. Contrary to popular belief, they do not damage what they are growing on, but can cause patios, drives, paths and steps to become slippery.

Moss, lichens and algae should not grow on clay bricks unless the area is heavily shaded, is under trees, or is not laid to an adequate fall. If such growth does occur and is considered undesirable then the area should be treated with a proprietary moss killer used in accordance with the manufacturer’s instructions.Such products take some days to be effective and work best when applied during a spell of dry weather. Any thick growths should be scraped off first and the chemical treatment well brushed in.

Some treatments leave a residue to discourage the re-growth of the moss and algae, but this will only be of limited value if the paving remains damp and in shade.

Non-chemical control

Dislodge moss from between paving by running a sharp knife along the cracks. Alternatively, use a block paving brush with a long handle, narrow head and wire bristles for effective cleaning without stooping
A pressure...

How do I remove oil and bitumen stains?

Oil stains

Oil does not penetrate readily into clay pavers, but if oil is spilt on the pavers, the spillage should be removed promptly with an absorbent material, such as paper towels. The oil should not be wiped up; otherwise this will spread the contamination on the surface of the paver.

Steam cleaning can be used on clay pavers to remove such staining, but if this is unsuccessful an emulsifying de-greaser should be employed. Brush with plenty of water to safe disposal. An alternative cleaning method is to brush the area with a strong detergent and hot water. This will not affect the colour of the clay paving.

Bitumen stains

Bitumen does not penetrate readily into clay paving. The best method of removal is to leave the bitumen until it has cooled. A paint scraper or a similar mechanical device can then often remove it. 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 a scouring powder and finally the whole area rinsed with clean water. Certain proprietary cleaning agents are available to remove bitumen, but these...

How do I prevent salt damage at the coast?

Please refer to our Technical guides under `SALT ZONES` and salt erosion of clay bricks.

If you have a property situated on the beachfront there is usually some degree of deterioration taking place! All bricks are porous and will absorb salt, and many factors are at play so it is impossible to say how long it will be before deterioration of the façade begins. The softer lime mortar used in external brickwork prior to the 1960's can be substantially affected by salt deterioration. This is more prevalent in the exposed location but buildings located 2-3 kilometres from the sea can also be affected. The mortar becomes soft and powdery.

More recent Calcium Silicate face bricks can still suffer from surface delamination. This occurs as the salt crystals adhere to the brickwork and are absorbed into the bricks. During rain the crystals will expand and then push the outer surface of the brickwork away. Once the hardened surface of the brickwork is lost, then the rate of deterioration of brickwork will accelerate. It is not possible to prevent the surface delamination of bricks.

We have however noticed that the higher temperatured bricks like steel blues are...

How do I remove cement stains on brick?

Remove large deposits with wooden implements to avoid damaging the paver surface. Following the pre-wetting of the area, treat the residue of mortar by careful application of a dilute hydrochloric acid solution or a proprietary cleaning solution. The application of the acid breaks down the cementitious components but is not damaging to clay pavers.

As with all cleaning procedures a rinsing operation should be carried out shortly after application, and care taken to dispose of run off solutions safely.

If the above method is not successful with coloured mortars, specialist advice from the coloured mortar supplier should be sought.

On the rare occasions when a vanadium efflorescence is present, hydrochloric acid based cleaners must not come into contact with the efflorescence, otherwise a dark stain will result which will become fixed on the surface.

Are clay bricks petrol & diesel resistant?

A burnt clay facebrick type product is resistant to petrol and diesel. For many years Caltex specified only clay pavers for their garage forecourts for this reason (Tarmac was never used as petrol and diesel attack it) Although petrol can stain bricks, they are easy to clean.

Acid resistant clay tanks are common in industry and these willl also cope best with petrol and diesel. We would suggest a specialized mortar and possibly a lining is used. There are many specialist suppliers – just search the net!

The acid and chemical resistant clay bricks are featured products in various construction and refractory applications and are available in various shapes and types such as Arch Bricks, Tapper Bricks, Sleeves, Tongue & Groove Bricks.

Chemical resistant clay bricks are used in following application areas:

Chemical plants: Dyes, Intermediates, Acids and Alkalies
Fertilizer Plants
Thermal power plants for chimney construction
Petrochemicals and refineries
Pharmaceuticals etc
Galvanizing Plants

Should I seal my paving?

Mark Hunter-Smith of Algoa Brick advises:

"Any form of sealant or dressing on a brick automatically turns a maintenance free product into one that has to be maintained as the sealer will weather and or peel off over time. The only time this has limited success is internal feature walls that are protected from the elements. Sealing traps moisture in the bricks and wall and cause softening and failure of the mortar. In most older buildings you will be able to see that the bricks to not fail, it is the mortar that crumbles or splits.

"Applying a sealer to an external paving situation is probably the hardest to do as it is totally exposed to weather as well as car tyre abrasion etc. It has no roof overhang to protect or vertical walls for rain to run down i.e horizontal surface taking full pounding. I do not think a sealer will last very long in this application especially in the high wear areas which can create a patchy type finish. Also a sealer makes the paver waterproof so rain water pooling occurs and also surface can become rather slippery.

"I would suggest rather a good clean with a high pressure setting of a garden hose using industrial type soap like...

What is the white, powdery substance on my bricks?

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

Efflorescence does not in any way influence the structural strength of clay bricks or pavers. Roman buildings that have been standing for 2 000 years can show efflorescence

A temporary efflorescence is particularly common on new brickwork and paving as soluble salts are dissolved and transported to the surface of the brickwork and paving by water. The efflorescence on new well fired brickwork and paving may be unsightly, but it will not cause damage unless the brickwork and paving are under-fired or soft-fired, in which case serious efflorescence can cause flaking of the surface of the brick or paver.

Efflorescence can occur from a variety of sources. Besides the brickwork, soluble salts can originate from the sand, mortar and the water used. Ground waters that are naturally salt-bearing can be drawn into the base of the brickwork and paving.

Remedies

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...