In this two part article, we first look at attending to brickwork tainted by air-borne pollution and then, everybody’s pet hate, graffiti. Part two deals with the cleaning of bricks contaminated by efflorescence.
Before attempting to remove dark pollution stains from your brickwork, make sure you have the proper safety clothing, including a hard hat, heavy duty waterproof gloves and industrial shoes (also waterproof). Since you will be using acid, this is no job for the inexperienced DIY person – rather find a painting and decorating service in your area.
If cleaning light-coloured bricks, start by scrubbing the entire wall with a 1:20 solution of hydrochloric acid and water. Strengthen the solution to 1:10 when cleaning dark coloured bricks. Mix the acid and water in a plastic bucket or basin, and then apply to the wall with a stiff scrubbing brush.
Begin by scrubbing the wall at the top left corner (assuming you’re right-handed) and move across the wall, and then downward using overlapping circular scrubbing motions. It is advisable to treat approximately one square meter, and then pressure-hose that area before moving to the next section of brick.
When pressure cleaning, be careful not to apply too much force, as intense jets of water can disturb the bonding cement and may even damage the brick face. Make sure you are positioned correctly in terms of distance from the wall, standing at least three feet away. Use a wide-sweeping action for best cleaning affect.
If this is sounding a bit hard, rather get a painting and decorating quote, and get on with something else you would rather be doing.
When cleaning off graffiti, work a thick layer of citrus-based gel over the entire painted surface. Now, work it into the crevices using a hard nail brush. Wipe off with a clean cloth, and then work in some more gel. Repeat the process until the graffiti disappears.
One of our regular London painters and decorators offers the following tip for removing unwanted graffiti. Cover the affected gel smeared wall with a plastic sheet taped over it. Leave this in place overnight to allow the gel to penetrate. Remember, the longer graffiti is left on the wall the more difficult it will be to remove.
A final pressure clean should be all that’s needed in the morning!