Floors in garages and workshops are generally made of unsealed concrete. This makes them vulnerable to oil stains, as raw concrete is porous and will begin to absorb oil the moment it is spilt.

In some cases, it can prove impossible to eradicate all traces of an oil stain, but if you act quickly and persevere you can generally get the stain to a point where it is largely unnoticeable.

Don’t Wait

It is far easier to successfully remove a fresh oil spill than one that has been left to sit for weeks or months. As time passes, the oil penetrates deeper and deeper into the concrete, becoming progressively more difficult to remove. When the oil hits the floor, then, don’t wait – act immediately.

Remove the Surface Oil

Two often-suggested ways of dealing with a puddle of oil are:

  • Wipe it up with rags or kitchen paper – this is very messy and runs the risk of rubbing the oil deeper into the concrete.
  • Squirt dishwashing liquid into it, wait for this to emulsify the oil, then hose it away – this, again, is very messy, and environmentally unfriendly to boot –  all that oil and detergent running into your garden? No thanks.

A far better way to attack that puddle is to dust it heavily with some sort of absorbent material, allow this to soak up the oil for a day or two, then remove the debris with a spade or brush and pan.

Materials you can use for this purpose include: cat litter (though the coarseness of the grains does not provide for the best possible contact with the floor), fullers earth, garden lime, sawdust and cement powder.

The Stain Itself

After you’ve removed the surface oil, or if the oil soaked in long ago, you’re left with a nasty dark blot on the floor. Ask five people how to deal with this and you’ll probably get five different answers – from drenching it in cola to sprinkling it with dishwashing powder.

Some of these home remedies can be reasonably effective, but many of them fail to take into account the actual nature of an oil stain in concrete. The oil has penetrated into the concrete. Dissolving the visible layer on top with a detergent or bleach does nothing to all the layers below.

To effectively treat an oil stain you need to draw the oil out of the concrete, break down its structure, and absorb the resulting mixture into a material that can then be easily transported away and disposed of. The method below ticks all the boxes.

An Effective Approach

1. Equip yourself with the appropriate safety gear, you’ll be using a dangerous chemical. Goggles and heavy rubber gloves are recommended.

2. Using a litre of water and about a litre of absorbent powder (ground up cat litter, Fuller’s earth, garden lime) make a spreadable paste. Note: you can’t use cement powder here as you’re also using water and the mixture will bond with your floor.

3. Add 120mls of trisodium phosphate (TSP) and mix into the paste.

4. Spread the paste over the stain.

5. Leave overnight or until the paste has thoroughly dried.

6. Remove the dried paste with the edge of a spade and a stiff brush.

7. Hose the area thoroughly.

8. If you are concerned that some of the TSP may still be active on the floor, neutralise it with a dusting of baking soda.

Repeat steps 1 – 7 until the stain is gone.

Oil stains can be stubborn, but with a little perseverance and some elbow grease that dirty, oil-spattered garage floor can be given a new lease of life.

Learn more about getting oil stains out of concrete with this video.

How to Get Oil Stains Out of a Concrete Floor, 3.8 out of 5 based on 4 ratings

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Comments

  1. Thanks Duncan for the useful tips.

    Once you have cleaned your concrete of stains and it has dried completely it is well worth sealing the surface with Kiwicare’s NO Leaks Waterproof Masonry Sealer available at good hardware stores throughout New Zealand. This will help protect your concrete floor or driveway from further stains and discolouration.

    For coloured brick and terracotta Kiwicare produce a specific Red Brick and Terracotta Sealer.

    If you have any questions contact Kiwicare.

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