• Chris Martin

Removing Tough Bore Stains from an Exposed Aggregate Driveway or Patio

Exposed aggregate is an extremely popular choice for Perth driveways and patios, it’s versatile and tough like concrete but it allows you to choose different styles and colours to suit your home. While exposed aggregate has many benefits, it’s is still susceptible to staining from bore water sprinklers.

In this article, we’ll explain why you’re getting brown and black stains and how to clean stains from the exposed aggregate.

What is Exposed Aggregate?


You may be hearing this term a lot when it comes to new homes or renovations but might not exactly understand what exposed aggregate is.


Aggregate is just a fancy way of saying mixture, so exposed aggregate is a mixture where the elements of the mixture are showing. Typically, the exposed aggregate that is used for driveways or patios is a mixture of concrete and other hard materials like stones or pebbles.


Exposed aggregate is installed by concrete professionals and they will use qualified techniques to bring the stones to the surface of the concrete, giving your driveway or patio a textured finish with a unique look.


Exposed aggregate comes in a variety of concrete colours and stone choices, giving home buyers and renovators a huge range of options to creating unique looks for their homes.



Why does Exposed Aggregate get Stained from Bore Water?


Like most building materials, exposed aggregate is vulnerable to staining for bore water and needs regular cleaning to maintain the desired look. Before we can talk about how to remove bore water stains we need to understand what is causing the stains.


Bore water is groundwater that contains all the excess minerals that are filtered out of our drinking water. The water we get from the tap in our kitchen is quite different from the water we use for irrigating our garden. Specifically, bore water has a high level of iron and other metals that have come from the earth where the water was pulled from.


Whenever the water from your bore sprinkler or hose sprays on to your exposed aggregate driveway or patio it leaves a small amount of iron on the surface. Over time the iron oxidises and forms a reddish-brown rust on the exposed aggregate.

In addition to the reddish rust stains, you may also notice black stains on your driveway. This is caused by either soil carbon or manganese oxide that has been sprayed onto the surface from the bore water.

You will see iron staining on many homes with bore water supplies and there are several steps you can take to remove the stains and ensure they don’t return for a while.



Exposed Aggregate Cleaning


When you decide to remove the bore water stains from exposed aggregate the first thing you need to do is give the surface a detailed clean. We recommend getting a high pressure clean to remove all traces of minerals, soil and debris from the surface. Any particles that remain on the concrete will continue to oxidise and stain.


You will then need to have your exposed aggregate acid washed to remove the iron stains from the concrete and the crevasses around the stones. Again, it is important that this step is done precisely. The small gaps around the stones in the concrete can retain the bore waters minerals and lead to further staining.



Acid washing needs to be done by a professional that is qualified to handle the hazardous acidic chemicals. Before you attempt to acid wash your exposed aggregate, speak to DJL Services for a free measure and quote.


Finally, we recommend applying a concrete sealant on your exposed aggregate driveway or patio to reduce the impact your bore water irrigation will have. Concrete sealing exposed aggregate adds a protective layer over the surface and fills in any tiny cracks in the concrete and around the stones that may become filled with mineral deposits.


Speak to DJL Services today to bring your driveway or patio back to sparkling best. We provide a free measure and quote as well as environmentally friendly high-pressure cleaning options.

DJL Services
High Pressure Cleaners

Tel: 0417 530 171

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