Man acid washing concrete flooring

If you’re looking to give your tired, old concrete surfaces a new lease on life, acid washing can be the answer. Acid washing is an effective and affordable method of restoring your old concrete surfaces back to their former glory. By using the appropriate methods and high-quality concrete cleaning chemicals, you can remove unsightly stains, algae, mould, and dirt from your concrete, restoring its original appearance, improving safety, and prolonging its lifespan.

Throughout this guide, we will walk you through the 10-step process of acid washing your concrete – from preparation to application and everything in between. We will also address common concerns, such as safety, cost, and effectiveness, ensuring you’re well-equipped with all the information you need to successfully revitalise your old concrete. 

What is Acid Washing and Why is it Important? 

Acid washing, also known as acid etching, is a process that rejuvenates the appearance and functionality of old and worn concrete surfaces. By applying a mixture of acid and water to the surface, a chemical reaction occurs to effectively remove dirt, grime, calcium, efflorescence and other contaminants, revealing the fresh and clean concrete underneath.

The main goal of acid washing is to improve the aesthetic appearance of your concrete, but it also serves other important purposes. It can help remove slippery algae and mould, making your concrete safer to walk on (especially in damp and wet conditions) as well as making sure your concrete is ready and safe to seal.  

The use of acids and concrete cleaning chemicals is an effective and proven method of restoring your concrete floors. The range of concrete cleaning chemicals offered at Australian Slate-Crete Supplies are of the highest quality, so you can easily achieve your concrete goals in no time. Our acid cleaners are specifically designed to facilitate the acid washing process before applying a concrete sealer. This cost-effective solution not only revitalises your concrete but also helps prevent expensive maintenance jobs down the line. With our high-quality products, you can confidently tackle your concrete projects and enjoy long-lasting results.

Uncovering the Advantages of Acid Washing Concrete

When it comes to reviving your old concrete surfaces, you might be wondering whether acid staining or washing is the right approach. Provided you take into account certain factors, such as the age, condition, and type of concrete, acid washing boasts numerous benefits. Concrete acid washing can provide three key advantages for your old concrete surfaces; let’s delve deeper into the pros of acid washing. 

Aesthetics – Breathe New Life into Your Old Concrete: 

Using the correct concrete chemicals can restore the original appearance of your concrete, making it look as good as new. Over time, concrete surfaces can become discoloured, stained, and dull due to exposure to the elements, dirt, and grime. Acid washing acts like a magic wand, dissolving and lifting away stubborn stains, revealing the true beauty of your concrete underneath. The process results in a refreshed and revitalised surface that not only looks better but also enhances the overall aesthetic appeal of your property. 

Slip No More – Safety Advantages of Acid Washing:

Mould, algae, and other slippery substances can accumulate on concrete surfaces, posing a significant safety hazard. These unwanted growths thrive in damp, shady areas and can lead to accidents and injuries on walkways, driveways, and patios. Acid washing effectively removes these growths, reducing the risk of slip-and-fall accidents and providing an overall cleaner and safer surface. By eliminating potential hazards, you’re also reducing the risk of costly liability issues. 

Reduce Maintenance – Prolonging the Life of Your Concrete:

Finally, acid washing your concrete is an excellent preventive maintenance measure. By removing contaminants and surface imperfections, the process ensures that your concrete remains in top condition for longer. With regular acid washing, you can prevent the need for more extensive repairs or even replacement of your concrete surfaces. By investing a little time and effort in acid washing, you’re safeguarding your concrete’s longevity and saving yourself money in the long run.

Acid Washing Old Concrete – Is it Possible?

In short – yes! Acid washing can work wonders on old concrete surfaces. You can safely acid wash old concrete if it is structurally sound and free of major cracks or damage. However, it is crucial to consider a few factors before you get started. The age, condition, type of concrete, and quality of concrete cleaning chemicals play a significant role in determining the success of the acid washing process. Let’s delve deeper into these factors below: 

Age 

When it comes to the age of the concrete, it’s important to realise that older surfaces may be more susceptible to damage during the acid washing process. As concrete ages, it may become weaker or develop hairline cracks that could be worsened by the application of acid. If your concrete surface is particularly old, it’s a good idea to consult a professional before proceeding with acid washing. 

Condition 

The condition of the concrete is another crucial consideration. If the surface has extensive cracks, crumbling, or other significant damage, acid washing may not be the most appropriate solution. In such situations, it might be more sensible to repair or replace the damaged concrete rather than attempting to revitalise it using acid washing. A professional assessment can help you determine the most suitable course of action based on the extent of damage. Severely damaged or cracked concrete may require professional repair or replacement rather than acid washing.

Type of Concrete 

Next, the type of concrete plays a role in determining whether acid washing is appropriate. While most concrete surfaces can benefit from acid washing, some specialised finishes such as coloured or stamped concrete may require additional care. As mentioned in the FAQs section, acid washing coloured or stamped concrete is possible, but you need to be cautious to avoid damaging the surface. Consult a professional if you’re unsure about the compatibility of acid washing with your specific concrete type. Some decorative or coloured concrete surfaces may not be suitable for acid washing. Consult a professional if you are unsure.

Quality of Products

Finally, selecting high-quality concrete cleaning chemicals is crucial for achieving effective, safe, and durable results when acid washing concrete. The choice of products can greatly impact the outcome of the acid washing process and the overall condition of your concrete surfaces. At Australian Slate-Crete Supplies, we offer a wide selection of top-quality concrete cleaning chemicals and free expert advice to secure the outcome of your next project, no matter the size. 

The Art of Acid Washing Concrete: A 10-Step Guide

By now it should be clear that acid washing is an effective and affordable method of refreshing and maintaining your old concrete surfaces. Our professionally approved process will guide you through the 10-step process of acid washing your concrete, from assessing the surface to evaluating the results.. Don’t let unsightly stains and discolouration detract from your property’s appeal – take action today and transform your old concrete with acid washing.

Step 1: Assessing the Surface

Before you begin, take a close look at your concrete surface. Check for any cracks, chips, or severe damage that might require professional attention. Remember that a concrete acid wash is best for relatively sound concrete surfaces with minor stains or discolouration.

Step 2: Gathering Supplies and Protective Gear

Safety first, folks! Ensure you have the right protective gear, including gloves, goggles, and a respirator mask. You’ll also need a plastic watering can or sprayer, a stiff-bristle broom or brush, a garden hose, and a bucket for mixing the acid solution.

Step 3: Cleaning the Concrete

Give your concrete surface a thorough clean by removing any debris, dirt or loose materials. A pressure washer is ideal for this task, but a good old-fashioned scrub with a stiff-bristle broom and water will do the trick too.

Step 4: Preparing the Acid Solution

Refer to the manufacturer’s instructions for the appropriate acid-to-water ratio. Generally, a 1:4 ratio of acid to water is recommended for most concrete surfaces. Always add the acid to the water (not the other way around!) to avoid any dangerous reactions.

Step 5: Testing a Small Area

Before going all-in, test the acid solution on a small, inconspicuous area of the concrete. This will help you determine if the concentration is right and how long the solution should be left on the surface.

Step 6: Applying the Acid Solution

Using a plastic watering can or sprayer, evenly apply the acid solution to the entire concrete surface. Be generous with the application, ensuring the surface is completely saturated.  A plastic watering can is the best method, as a sprayer may apply too little acid. Ideally acid should be applied to small, manageable areas and done in stages.  10m2 is the ideal amount to do at any one time.

Step 7: Scrubbing the Surface

It’s time for the main event– washing! Usually scrubbing is not required when acid washing, as the acid is chemically cleaning it, thus doing the hard work for you. Using a broom to agitate and turn the acid over is usually sufficient.  On stubborn staining, vigorously scrub the surface with a stiff-bristle broom or brush, working the acid solution into the concrete. This helps to break down stains, discolouration, and other surface imperfections.

Step 8: Neutralising the Acid

After the acid has worked its magic (usually 10-15 minutes), it’s time to neutralise it. Mix a neutralising solution of baking soda and water (1 cup of baking soda to 5 gallons of water) and apply it to the surface using your broom or brush.

Step 9: Rinsing Thoroughly

Use your garden hose to thoroughly rinse the concrete surface, ensuring all traces of the acid solution and neutralising agent are gone. This step is crucial for preventing any lingering acid damage.  Pressure washing is highly recommended at this stage to remove any loosened latency.

Step 10: Evaluating the Results

Once the surface is completely dry, assess the results of your acid wash. If you’re not satisfied with the outcome, you may need to repeat the process or consider seeking professional help.

Remember that acid washing is just one part of the concrete revitalisation journey. For a comprehensive approach, refer to other sections in this guide, such as the benefits of acid washing, DIY vs. hiring a professional, and best practices for acid washing concrete. Alternatively you can reach out to the experts at Australian Slate-Crete Supply – simply message us or call 03 9408 7722. 

DIY Acid Washing vs. Hiring a Professional

FAQs: Everything You Need to Know About Acid Washing Concrete


The decision between taking on a DIY acid washing project or hiring a professional can be a tough one. To assist you in making the best choice, let’s explore the cost and time considerations, weigh the pros and cons of each option, and discuss when it’s time to seek professional help.

Cost and Time Considerations:
When it comes to the cost of acid washing your concrete, doing it yourself can be a more budget-friendly option. Purchasing the necessary supplies and protective gear may set you back a few hundred dollars, whereas hiring a professional could cost significantly more. However, the time investment for a DIY project may be substantial, particularly for those new to the process. A professional, on the other hand, can complete the job quickly and efficiently, saving you precious time and energy.

Pros and Cons:
DIY acid washing offers the satisfaction of accomplishing a home improvement project on your own, as well as the potential for cost savings. This hands-on approach also allows you to control every aspect of the process, tailoring it to your preferences and needs. However, tackling the job yourself can be time-consuming and potentially risky if you’re not experienced in handling chemicals or are unsure of proper safety procedures.

Hiring a professional eliminates the need to worry about safety hazards and offers peace of mind that the job will be done correctly. Professionals have the experience and expertise to handle any complications that may arise, ensuring a smooth and successful acid washing process. However, this option is generally more expensive and takes the control out of your hands.

When to Seek Professional Help:
In some cases, it’s best to call in the experts. If your concrete surface is severely damaged or if you’re unsure about the age, condition, or type of concrete, a professional consultation is recommended. Additionally, if you’re uncomfortable handling potentially dangerous chemicals or lack the time and energy for a DIY project, it’s wise to seek professional assistance.

At the end of the day, the choice between DIY acid washing and hiring a professional ultimately depends on your personal preferences, budget, and comfort level. By considering the factors outlined in this section, you’ll be well-equipped to make an informed decision that best suits your needs and helps revitalise your old concrete surfaces.

Mastering the Art of Acid Washing Concrete – Best Practices from Industry Experts

Safety First: Tips and Precautions
A crucial aspect of acid washing concrete is prioritising safety, as working with acid can be potentially hazardous if not handled correctly. Always wear appropriate protective gear such as gloves, goggles, and a mask to minimise the risk of injury. Additionally, ensure proper ventilation in the area where you’re working, and avoid mixing acids with other chemicals, as this can lead to dangerous reactions. It’s also a good idea to have a neutralising agent and a water source nearby in case of accidents or spills.

Choosing the Perfect Acid for the Job
While several types of acids can be used for acid washing concrete, muriatic acid (also known as hydrochloric acid) is the most common choice due to its effectiveness and affordability. However, be cautious with the concentration of the acid – a solution that is too strong can damage your concrete. A safe ratio to start with is one part acid to ten parts water, but always consult the manufacturer’s guidelines and test a small, inconspicuous area before moving on to the rest of the surface. For more information, you can explore our acid and concrete cleaning chemicals. Can’t find what you’re looking for or want to chat more about concrete? Get in touch with the experts at Australian Slate-Crete Supply  by sending us a message or calling 03 9408 7722. 

Timing is Everything: When to Acid Wash New Concrete
We’ve discussed transforming your old concrete in every which way, but it’s also an essential step after the installation of new concrete. The timing for acid washing new concrete is crucial, as doing it too soon can weaken the surface, while waiting too long might make it difficult to remove any stubborn stains or marks. Generally, it is best to wait at least 28 days after pouring new concrete before acid washing, as this allows the concrete to cure properly. However, this timeframe can vary depending on the specific project and environmental conditions, so consult with a professional if you’re unsure.

By following these best practices, you’ll be well on your way to setting up your concrete for success. Acid washing can be a transformative process, but it’s essential to approach it with care and consideration to achieve the best possible outcome. So, roll up your sleeves, gear up, and let’s get that concrete looking brand new!


How long after pouring concrete should you acid wash it?

Timing is crucial when it comes to acid washing your freshly poured concrete. Generally, it’s recommended to wait at least 14 days after pouring before attempting an acid wash. This allows the concrete to cure and reach an optimal level of hardness. However, it’s always a good idea to consult with a professional or refer to the guidelines provided by your concrete supplier for specific recommendations based on the type and mix of concrete you’re working with.

What is the best acid to clean concrete?

Muriatic acid (also known as hydrochloric acid) is the most commonly used acid for cleaning concrete surfaces. It is highly effective in removing dirt, grime, and stains. However, it’s crucial to handle muriatic acid with care, as it is a potent and corrosive substance. The best type of acid also depends on the size of the job and your budget – check out the range of acid and cleaning chemicals offered by Australian-Slate Crete Supplies.

How do you neutralise concrete after an acid wash?

Neutralising concrete post-acid wash is essential to halt the corrosive action of the acid and avoid any further damage to the surface. To do this, mix a neutralising solution of baking soda and water (approximately one cup of baking soda per gallon of water). Thoroughly douse the acid-washed surface with the solution, ensuring complete coverage. You may need to apply multiple rounds of the solution to ensure full neutralisation. Finally, rinse the surface with clean water to remove any remaining residue.

What do you use to acid wash concrete?

To acid wash concrete, you’ll need the following supplies: a suitable acid, a watering can or sprayer for applying the acid, a stiff-bristled brush or broom for scrubbing, protective gear (goggles, gloves, and boots), a neutralising solution (baking soda and water) and a pressure washer. Keep in mind that it’s crucial to follow all safety precautions and guidelines when working with acids.

Can you acid wash coloured or stamped concrete?

Generally yes, but in some circumstances it can affect the colour. In such cases, it’s best to consult with a professional or the concrete supplier for specific recommendations. If you decide to proceed, test the acid solution on a small, inconspicuous area first to assess the potential impact on the colour and pattern.

How often should you acid wash your concrete surfaces?

The frequency of acid washing depends on the specific needs and conditions of your concrete surfaces. Generally, it’s not necessary to acid wash concrete more than once every few years. However, if your concrete is exposed to harsh conditions, heavy foot traffic, or persistent staining, more frequent acid washing may be required to maintain a clean and aesthetically appealing surface.  If the surface is sealed after acid washing, it will most likely not need acid washing again, or not for a very long time.

Can acid washing damage concrete?

While acid washing is an effective method for cleaning and revitalising concrete surfaces, improper handling or excessive use of acids can lead to potential damage. This includes etching, discolouration, or even weakening of the concrete. To minimise the risks, always follow the safety guidelines, use the appropriate acid concentration, and neutralise the surface after the acid wash. Additionally, seek professional advice if you’re unsure about the process or if your concrete surface is in poor condition.

Bringing It All Together: Revitalising Your Concrete Surfaces

In this comprehensive guide, we have explored the importance and benefits of acid washing old concrete surfaces. Acid washing not only restores the original appearance of concrete but also improves safety by removing slippery algae and mold, while extending the lifespan of the concrete. By now, you should have a solid understanding of the essential steps involved in acid washing and the factors to consider when deciding between a DIY approach or hiring a professional.

In summary, preparation is key when it comes to acid washing. As outlined in the 10-step guide, taking the time to assess your surface, gather supplies, and follow safety precautions sets the stage for success. Additionally, adhering to best practices for acid washing concrete, such as selecting the appropriate acid, timing the process correctly, and considering environmental factors, is particularly important. 

As you embark on revitalising your old concrete surfaces, remember that acid washing can be a highly effective solution when approached correctly. Address any concerns, seek advice, and educate yourself to achieve the best results. Armed with the knowledge gained from this guide, you are now ready to make an informed decision and bring new life to your concrete surfaces. Embrace the transformative power of acid washing and enjoy refreshed outdoor living spaces! 

We Provide Quality Concrete Supplies in Melbourne

Whether it’s an at-home task or big commercial job, successful acid washing starts with selecting high-quality concrete products. With an extensive-range and 50 years of concrete knowledge, Australian Slate Crete is the top supplier of concrete cleaning products in Melbourne and its surrounding areas. We offer the latest technology in concrete cleaning chemicals and solvents – check out the right surface cleaners and repair solutions from our extensive range

If you’re unsure where to begin, our dedicated team of experts at Australian Slate-Crete Supplies is here to help. Whether you need assistance in choosing the ideal concrete cleaning chemical for your project or have any inquiries, feel free to reach out to us by sending a message or giving us a call at 03 9408 7722.