Effective Concrete Cleaning by John from All Exterior Cleaning
The concrete surfaces around your home, office, factory, workshop, cafe etc. will eventually gather dirt and moisture that feeds the mould, get tannin stains from wet leaves, have bird & bat droppings, cars & trucks will leave oil stains, and there will be grease marks from food & the BBQ. These are all ugly and can be slippery.
Your concrete needs to be cleaned regularly to maintain its appearance and be safe to walk on.
Improve the look and value of your home and business.
You need to protect your investment, whether you work there, live there or rent it out. Reclaim your valuable, clean and welcoming home or business.
While concrete can be cleaned with just high-pressure pressure water, this doesn’t
- kill the mould;
- lift the deep organic stains, oil & grease; or
- bleach the tannin stains.
It is a simple principle “kill the mould, lift the dirt, wash it all away”. But you need the right cleaning solution at the right strength to actually kill the mould and lift the stains. The water pressure needs to be just enough to lift the dirt without damaging the concrete, and the rinsing needs to be careful and thorough to rinse it all away.
How to clean concrete
- Blow dirt, leaves & other loose debris;
- Spot clean any heavy or special stains;
- The cleaning solution is applied and reapplied until everything is thoroughly wet, then scrubbed with a stiff broom if needed, and allowed to penetrate and kill the mould & lift the dirt;
- Cleaning is done with either low, medium or high pressure water (depending on how strong the surface is);
- The concrete is then rinsed with low pressure water;
- Deep stains may remain and they are re-treated and washed again.
Many people think that an acid is needed to clean concrete, but this is not true. Acids generally break minerals apart, and as concrete is made of natural minerals, many acids will break the concrete apart and (hopefully) take any dirt or other contaminates with it. This method breaks up the smooth top surface and leaves you with a rougher surface that catches more dirt (getting dirtier quicker). A weak acid (like Oxalic acid) can be used to “brighten” old concrete, but this shouldn’t be done very often due to the damage it can cause.
Bleaches and degreasers will not damage the concrete as they only break up fats, oils and other organic matter.
Sealing your concrete
Now clean, your concrete driveway, carpark and paths should be protected from more mould, dirt, oil etc with a high quality sealer.
- penetrating (silicone) – invisible, doesn’t change the slip resistance and long wearing, can be walked on a couple of hours after application
- surface coating, clear and coloured (acrylic, urethane) – a coating that can wear or chip, wet look gloss or satin finish, takes days to cure