Is nature leaving its mark on your driveway?
Our city is full of oak trees, hence the name “Royal Oak.” When the acorns drop from the oak trees, they can leave dark stains on cement driveways.
These nuts are high in tannins. Think of acorns like red wine. They are high in tannins and can leave dark stains on clothing or carpeting.
When the tannins are spread over a porous surface, like concrete, the result is a dark stain with a greenish or golden cast that looks like someone threw a pot of tea on your driveway. So what happens when the acorns fall onto your driveway and the rain washes over them.
There are a couple of remedies you might try.
One of the safest is to use a product called CLR. Mixed with a little warm water and brushed on the area should remove some stains. It might require a couple of applications, or you could try it at full strength.
As with anything, you should first test a small inconspicuous area of your driveway to ensure there is no adverse effect.
We feel the best way to remove the stain is to use Muriatic Acid. Usually available at hardware, paint, or masonry supply stores.
This product is highly corrosive and poisonous, and care should be taken when using Muriatic Acid. Wear vinyl gloves, eye protection, and old clothes and shoes.
Mix 1 part acid to 20 parts water. It’s essential to add acid to the water. You can gradually add aci to the mixture to strengthen it.
Apply the acid with a scrub brush. The solution should bubble when applied to the concrete if it’s mixed strong enough.
Let it sit for one to two minutes, and then flush with plenty of water from the garden hose.