Are you also completely enamored with the warm, authentic look that limewashing brings? We totally understand! However, limewashing requires a thoughtful approach. There’s much more to it than just painting white lime on the walls.
One of the concerns we often hear is that people want to limewash a facade that has been treated with a water repellent. Can you still limewash then? And if so, how do you go about it?
What is a Water Repellent Again?
A water repellent is a colorless silicone-based product that is applied deep into the pores of a facade brick. It forms an invisible barrier against rainwater but still allows vapor to escape. This keeps the wall dry and better protected against moss, frost damage, and pollution.
Water repellent is often used in renovation projects to make old facades water-resistant without altering the appearance of the brick. At first glance, this seems ideal, but it also has a downside: it makes the substrate less suitable for new finishes, such as limewashing or painting.
Why Limewashing over Water Repellent is Problematic
Limewash is a breathable finish based on lime or cement, which adheres to the pores of the stone with a block brush. For good adhesion, the substrate must be absorbent. . Natural bricks, with their pores, are the perfect substrate for limewash. But if that facade has previously been treated with a water repellent, that absorbency is greatly reduced.
The result? The limewash remains on the surface, adheres poorly, and will peel or show stains more quickly. . At first glance, everything seems to be going well, but within a few months or years, the limewash may start to come off. This is, of course, a waste of the work and the investment.
How Do You Know if There’s Water Repellent on your Wall?
In many cases, the owner doesn’t know if water repellent was ever applied. Perhaps it was done years ago, by a previous occupant. Fortunately, this is easy to test.
By applying a little water to different spots on the wall, you can detect a water repellent. If the water is absorbed directly into the stone, there is probably no water repellent. However, if the water beads and runs off the wall, then the facade has been treated.
What if You Still Want to Limewash a Water Repellent-Treated Wall?
Fortunately, an old water repellent treatment doesn’t automatically mean that limewashing is impossible. There are ways to make the wall suitable again. Though this requires extra preparation, expertise, and sometimes patience.
- Roughening or blasting the surface
A commonly used method is mechanically removing the water repellent layer by sandblasting or thoroughly brushing the facade. This reopens the top layer of the brick and makes it absorbent again, allowing the limewash to adhere properly. Naturally, it’s best to leave this job to a professional to avoid damage. - Chemical cleaning
In some cases, the water repellent layer can be removed using special cleaning agents that break down the silicone bonds. This too requires the right products and experience, as each facade needs a unique approach. - Waiting and retesting
If the water repellent was applied more than 10 years ago, its effectiveness may have already significantly decreased. In that case, you might choose to wait until the product has completely worn off. We can potentially accelerate this process and then test.
Solusio: your Facade Expert
The answer to the question “Can you limewash a wall with a water repellent?” is: not without more. A water repellent significantly complicates limewashing. But it doesn’t have to be an insurmountable obstacle. n.
At Solusio, we always thoroughly examine the condition of the facade before starting a project. We test the surface, advise on possible preparations, and discuss with you which approach is most suitable. Whether it’s limewashing, plastering, or other facade finishes, we provide a beautiful solution that lasts for decades.
Do you want to know if your facade is suitable for limewashing, even after a water repellent treatment? Contact Solusio for a free site visit and professional tailored advice. This way, you can be sure of a facade that is not only beautiful but also long-lasting.