There’s nothing more disheartening than spending time and money on a beautiful new patio or pathway, only to see it marred by a mysterious white, chalky residue weeks later. This common issue, known as efflorescence, can make even the most premium paving look neglected.
But what if we told you that in most cases, it’s entirely preventable?
The secret doesn’t lie in a magic sealant or a different product. Often, it’s about how you use the grout you already have. At Forest Stone, we turned to a true expert to get the definitive guide on using Flowpoint. We sat down with trusted local landscaper Joe Irving of Aurum Hortis, whose impeccable work is a testament to his methods, to uncover his process for using Flowpoint grout without the risk of efflorescence.
The overarching theme? It’s all about water management.
In this guide, we’ll walk you through Joe’s five key principles, backed by his years of experience, to help you achieve a pristine, professional finish that stands the test of time.
What is Efflorescence and Why Does it Happen with Grout?
First, let’s demystify the enemy. Efflorescence is a crystalline, salty deposit that appears on the surface of masonry, concrete, and stone paving. It’s not a stain from the outside, but rather soluble salts and minerals being transported out of the material itself.
When you mix cement-based products like Flowpoint with water, these salts dissolve. As the grout cures and the water within it migrates to the surface to evaporate, it brings these dissolved salts with it. They remain on the surface once the water evaporates, leaving behind the unsightly white haze.
The more water in the system, the more readily these salts can dissolve and travel. This is why Joe Irving’s water-conscious methodology is so effective.
The Method: 5 Steps to a Flawless Finish with Flowpoint
Joe’s approach is a holistic system where each step is designed to minimise excess water and ensure a clean, controlled installation.
1. The Foundation: Don’t Mix Flowpoint Too Wet
This is the single most important step. The temptation, especially on a warm day, is to add a little extra water to make the grout more workable. This is a critical mistake.
Joe’s Advice: “I found over time using Flowpoint… people will knock it up far too wet. So, when we grouted this in the winter, I think Flowpoint recommend 4.2l of water per bag, but we used four.”
The Professional Spec:
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Follow the Guidelines (Mostly): The manufacturer’s instructions are a great starting point, often suggesting around 4.2 litres per 20kg bag.
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Adjust for Conditions: As Joe suggests, slightly reduce the water content. Aim for a consistent 4 – 4.2 litres per bag, using the lower end in cooler, damper conditions where evaporation is slower and the air is wetter.
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The Perfect Consistency: The mixed Flowpoint should be smooth, creamy, and paste-like, not watery or soupy. It should hold its shape when worked.
Why it Works: A stiffer mix contains less free water. This means there’s less water available to dissolve internal salts and transport them to the surface, drastically reducing the primary cause of efflorescence.
2. Work in Manageable Batches: Control is Key
Speed and efficiency are vital in landscaping, but not at the expense of the final result. Mixing too much grout at once is a common error that leads to rushed work and, ultimately, problems.
Joe’s Workflow: “We normally do things as teams of 3 or 2, so we don’t knock up a huge amount of grout at once- we work one bag at a time.”
The Professional Spec:
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One Bag at a Time: Especially for smaller teams, mixing a single bag ensures you can apply, work, and clean the grout well within its specified working time.
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Plan Your Area: Gauge how much area one bag can cover and don’t over-commit. It’s far better to mix a second bag than to rush and make mistakes with a large batch that is starting to set.
Why it Works: This prevents the grout from beginning to cure in the bucket and ensures you have ample time for the crucial cleaning stages without being rushed. Rushing leads to over-wetting, which is exactly what we’re trying to avoid.
3. The First Clean: Master the Neoprene Squeegee
Forget flooding the area with water for the initial clean. The first removal of excess grout should be a largely dry process.
The Professional Spec:
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Tool Up: Use a high-quality, flexible neoprene squeegee. Pro-Tiler Tools do some good options for this.
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The Technique: After spreading the Flowpoint into the joints, hold the squeegee at a 45-degree angle and firmly drag it across the surface of the paving. This efficiently scrapes the vast majority of the surplus grout off the surface, leaving the joints full and the slabs relatively clean.
Why it Works: This mechanical removal method uses zero water. By taking 90% of the grout off the surface this way, you significantly reduce the amount of residue that needs to be washed off later, meaning you’ll use less water overall.
4. The Final Clean: The Washboy Method (Done Right)
The washboy is an indispensable tool for the professional landscaper, but its effectiveness hinges on correct usage. This is not a power washer.
Joe’s Warning: “A lot of people do it, you see on, on social media- they’ll just jet wash it off. But for one you sort of take the finish off the top so the surface becomes really like granular… you’re also flooding the grout with water which will have to come back out at some point – invariably causing a lot of efflorescence in the process”
The Professional Spec:
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Use a Washboy: A washboy consists of a water tank, a sponge cleaning paddle and some cleaning rollers. It allows for controlled, minimal water use and clean working.
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The Technique: Use the sponge (with clean water from the tank) in a diagonal direction to the paving joins and wipe any grout residue from the surface of the paving as you go. Ensure the sponge is clean each time and don’t have the sponge too wet. You may have to do several passes. After this process the surface should be clean and almost dry. Replace the water in the washboy tank regularly.
Why it Works: The washboy system uses a minimal, controlled amount of water and, crucially, removes that dirty water from the surface. This prevents the grout slurry from being forced into the pores of the stone or sitting on the surface to help cause efflorescence and residue marks.
5. The Golden Rule: Keep Your Water Clean
This is the simplest step but one that is most often overlooked. Using dirty water is like bathing in a muddy puddle – you’re just spreading the problem.
Joe’s Golden Rule: “It’s very important to note with Flowpoint that, if you’re using washboys is to clean the water out after every bag.”
The Professional Spec:
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Refresh After Every Bag: Without fail, after you have finished cleaning the area from one bag of grout, empty the dirty water from your washboy tank.
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Refill with Clean Water: Refill the tank with fresh, clean water before you begin cleaning the next section or batch.
Why it Works: Using dirty, grout-laden water means you are essentially smearing a thin, cementitious slurry over your entire paving surface. As this film dries, it creates a perfect layer for efflorescence to form on, undoing all your careful work. Clean water ensures you are truly cleaning the slabs, not re-contaminating them.
Common Mistakes to Avoid: A Summary of How to Avoid Efflorescence When Using Flowpoint
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Mistake 1: Mixing too wet. This is the root cause of many efflorescence issues.
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Mistake 2: Using a jet washer for cleaning. This erodes the grout, damages the paver’s surface, and drives dirty water into the joints, creating a perfect storm for efflorescence and puddling on riven surfaces.
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Mistake 3: Using dirty washboy water. You are painting your patio with a paste of efflorescence-ready salts and grout remnants.
Conclusion: Precision Over Power
Achieving a perfect, efflorescence-free finish with Flowpoint grout isn’t about finding a secret product; it’s about adopting a precise, disciplined methodology. As Joe Irving of Aurum Hortis demonstrates, the key is to respect the product and control the water at every single stage:
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Mix it with the right amount of water for the conditions.
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Work in small, controlled batches.
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Remove the bulk mechanically with a squeegee.
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Finish with a washboy using minimal, clean water.
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Never, ever use dirty water.
By following this professional approach, you elevate your work from amateur to expert. You ensure that the beauty of your Forest Stone paving is visible from day one and remains that way for years to come, with no unsightly white haze to detract from your hard work.
Ready to start your project with confidence? Explore our full range of premium paving here, and don’t hesitate to contact us for more expert advice.
