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Once your paver project is complete, you do not want to have to deal with issues in the stone emerging. Some of these issues are minor, but some of them can point to poor construction practices of the interlocking concrete pavement. One such issue that could be one or the other is the presence of efflorescence. It shows up as a white residue on the surface of the pavers and can be cleaned quite easily. However, if the efflorescence continues to appear you may have a bigger problem in the bedding material and base of your paver project.
Cleaning Efflorescence from Pavers
It is important to note that the entire surface of the pavers must be cleaned prior to sealing your pavers. If your project is sealed before you clean the efflorescence or other stains from your pavers, you will not be able to remove them. Furthermore, the moisture present in the stone will cause hazing under your sealer and it will not look appealing. It is important to continue with cleaning the surface of your project before you seal.
Efflorescence is a mineral residue that appears on the surface of your pavers because of the presence of moisture. It is a natural by-product of concrete and is completely normal. An abundance of it right off the pallet would be a problem that you would want to raise with your supplier or manufacturer prior to laying the product. However, a little bit of it can be quite easily cleaned by following these steps outlined below. If efflorescence continues to reappear after cleaning or for seasons after the project has been installed, this points to a problem of moisture beneath the stone. This is typically caused by poor drainage and you should refer to the heading below on preventing efflorescence.
Here are some important tips to know prior to learning the steps to clean the efflorescence:
If polymeric sand or another jointing compound has been newly installed in the joints of the pavers, you need to allow them to cure for at least 48 hours. Additionally, it should not be used on newly installed pavers as they may not have had the time required to fully cure depending on when they were manufactured. Allow for a minimum of 60 days before you use a cleaner on the pavers. Refer to the polymeric sand or efflorescence cleaner manufacturer’s instructions for more guidance on these timelines. You do not want the efflorescence cleaner to dry on the surface of the pavers. The cleaner is diluted with water and rinsed off in sections. Use the cleaner on a small area to test the affects on the pavers before continuing with the entire project.
You will need to wear neoprene chemical resistant gloves when handling this product and safety goggles.
- Wet the pavement with water and heavily saturate the surrounding vegetation.
- Using a pump sprayed with larger quantity cans of the cleaner or a sprayer attachment to a hose and jug of cleaner supplied by the manufacturer, dilute the product at a rate that is specified by the manufacturer.
- Apply the product to the surface of a 40 square foot area and wait for one minute to allow the product to react. This will show as a foaming action on the surface of the pavers. The manufacturer will have a specified square footage that can be adhered to in the application of the cleaner as a guide to know how much to use on a specific area.
- Use a hard bristle brush to scrub the surface vigorously.
- Rinse the surface with water and continue to the next 40 square foot section. Continue with these steps until complete.
- At the end, rinse the surface thoroughly and ensure there is no more foaming action on the surface of the pavement.
- Depending on the presence of efflorescence on the surface of the pavers and even in the pavers, you may require an additional cleaning.
A good efflorescence cleaner will pull the efflorescence from inside the stone, thoroughly cleaning the residue. It is important to always consult with the manufacturer and read their listed instructions if they vary slightly from the above listed directions.
Best Efflorescence Cleaner for Pavers
Ultimately efflorescence cleaner is a diluted chemical. You are likely going to find a similar concoction of product from manufacturer to manufacturer. You may find that one may provide slightly better results than the other or you just prefer a certain brand over the other. But for the most part, if a hardscape supplier stocks a certain product you are likely not going to go wrong with it as an efflorescence cleaner. You typically want to get a product that has no hydrochloric acid in it, as this would cause permanent damage to the surface of the pavers.
How to Prevent Efflorescence on Stone
Efflorescence will continue to come to the surface of your paver project if there moisture present. There can only be moisture present if there is poor drainage underneath the pavers. This is why proper construction practices in the building of the project is important. An open graded base can be a solution to allow for the water that enters the system to flow through it with minimal resistance allowing little to no moisture beneath the pavers. This open graded base uses a clean stone that has been washed which removes the fines that would be present in the aggregate. With no fines in the base material, water can freely flow through the stone. This is achieved with a 3/4″ angular crushed clean stone as the base material and a 1/4″ angular crushed clean stone or HPB as the bedding layer.
Alternatively, a dense graded base with 3/4″ crushed down to fines or Granular “A” can be used as the base of the project with a Concrete Sand on top as the bedding layer to allow for appropriate drainage to the project. However if stone dust or limestone screenings are used, drainage will be prevented allowing for water to sit directly below the pavers throughout the season. This will cause the reappearance of efflorescence on the surface of the pavers, along with many other problems that will be experienced due to this water accumulation. This is why using the proper materials to construct a project is crucial to the longevity and appearance of the project.
Typically after one cleaning, efflorescence should not reappear. Though we have had to complete two or three cleanings before to remove efflorescence from the surface of a paving project prior to sealing. There are times when the efflorescence is really bad that the product should be returned to the supplier or manufacturer as this is a quality control issue.