Paving Stones: To Seal or Not to Seal?

Do I Need to Seal My Pavers?

The short answer is yes. Applying sealer to your pavers is a crucial step in maintaining their appearance and longevity. Whether you have a patio, walkway, driveway, or pool deck constructed with pavers, using a sealant will keep them looking as pristine as the day they were laid.

Over-application however, can be detrimental, leading to a cloudy appearance. It's important to know the right time for resealing to maintain the desired aesthetic. This guide will help you understand when and how to properly seal your pavers.

Do Concrete Pavers Need Sealing?

Absolutely. Due to their porous nature, concrete pavers are susceptible to stains if left unsealed. Applying a sealant not only prevents staining but also aids in preserving the colour.

Does the Type of Sealant Finish Affect Protection?

Paver sealants come in two main finishes: film-forming (giving a gloss or semi-gloss look) and non-film-forming (resulting in a matte appearance). Film-forming sealants, including types that enhance the pavers' appearance with a Wet Look or Clear Look, provide superior protection by forming a physical barrier on the surface. Non-film-forming sealants, offering a Natural Look or Color Boost, also provide solid protection and tend to last longer.

When Should New Pavers Be Sealed?

The timing for sealing new pavers depends on the type of sealant used. For non-film-forming sealants, a week is sufficient. However, if you're using a film-forming sealant, it's best to wait 30 days to ensure no moisture is trapped underneath the sealant layer.

Preparation Before Sealing

Pressure cleaning your pavers is a crucial step before sealing. This not only removes surface contaminants but also opens the pores of the pavers for better sealant absorption. For older pavers, this preparation step helps remove any efflorescence or stains, preparing the surface for sealing.

Optimal Conditions for Applying Sealant

During the Summer the necessary drying time post-clean is typically a few hours. The ideal temperature for sealant application is between 10-30 degrees Celsius. For solvent-based sealants, which evaporate more quickly, cooler temperatures are preferable.

Frequency of Reapplication

As a general guideline, resealing pavers every 2-3 years is recommended. Signs of wear on film-forming sealants and noticeable colour changes during wet conditions for non-film-forming sealants can indicate it's time to reapply. It's important to remember that pavers may appear darker after heavy rainfall, but this should not be confused with sealant failure.

Solvent Based Sealers vs Water Based Sealers

A Time and Place For Each

The discussion around reducing the content of volatile organic compounds (VOCs) in products like paints and coatings has gained prominence, especially as regulations become stricter nationwide. These regulations aim to lower VOC levels in numerous applications, making the choice of concrete sealers—a critical component in construction—increasingly significant for project planning.

Concrete sealers, essential for protecting and enhancing concrete surfaces, are available in both water-based and solvent-based formulations. Despite their differences, both types are effective in sealing concrete, offering a mix of aesthetic and protective benefits. After the concrete has cured, these sealers provide a barrier against wear, stains, and chemical damage, enhancing the surface's appearance with added gloss and colour retention.

Technology advancements have introduced high-quality acrylic sealer options, available in both water-based and solvent-based varieties. These sealers are renowned for their UV resistance, owed to their 100% acrylic polymer composition. Whether water or solvent-based, the sealers function by forming a continuous, clear coating on the concrete. Water-based sealers utilize polymer particles dispersed in water, which coalesce into a seamless coating as the water evaporates. Solvent-based sealers, on the other hand, comprise a polymer solution that forms a cohesive film as the solvent dissipates, leaving a glossy finish.

Both water and solvent-based sealers share several benefits, including durability, ease of application, and UV resistance. They are designed to protect concrete from various elements and stains, with some of the best performing acrylic sealers lasting up to three years outdoors. These sealers can be applied through spraying or rolling, making them convenient for a range of projects.

However, there are notable differences between the two types of sealers. Solvent-based sealers typically provide a glossier finish that enhances the underlying concrete colour due to their excellent penetration and wet-out properties. In contrast, water-based sealers have a milky white appearance upon application and cure to a matte finish, due to the light-scattering properties of the polymer particles.

Water-based sealers offer additional advantages in terms of safety and convenience. They are nonflammable, emit no strong solvent odours, and can be cleaned up easily, which can save significant time on a job site.

In conclusion, both water-based and solvent-based sealers offer effective protection and enhancement for concrete surfaces, with their own set of characteristics suitable for different project requirements. Water-based sealers, in particular, stand out for those seeking low-VOC options that are user-friendly and environmentally considerate, without compromising on performance and durability.

4 Essential Tips For Maintaining Your Concrete Driveway

Concrete driveways are a preferred choice for many homeowners due to their durability and resilience. Yet, if not properly looked after, they can suffer from wear such as cracking, fading and other forms of damage. Overlooking the upkeep of your concrete driveway will undoubtedly lead to expensive repairs.

To ensure your concrete driveway remains in good condition for years to come, it's crucial to care for it correctly. Below are four essential tips for maintaining your concrete driveway.

Apply a Sealant

Concrete's robustness makes it an excellent material for driveways, but water penetration can be its downfall. When water seeps into concrete and then freezes during colder temperatures, it can cause expansion, leading to the formation and widening of cracks.

To effectively seal your driveway, begin with a power wash to eliminate dirt, moss, and other residues. These can hinder the sealant's ability to bond with the concrete. Allow the driveway to dry fully before you apply the sealant.

Has your concrete been sealed previously? Ensure the sealer you select is compatible with the existing product. Remember: solvent-based sealers may be applied over water-based sealers, but not vice versa.

• Film-Forming Sealer: Solvent-based, acrylic sealer. Available in high-gloss and low-gloss options, often referred to as “wet-look sealer”. Recommended for stamped concrete, exposed aggregate and brushed concrete that is dated or has been previously sealed with an unknown product. Lasts 2-3 years.

• Penetrating Sealer: Water-based blend of Silane & Siloxane. A natural finish sealer recommended for freshly placed, brushed concrete. Lasts 5-10 years.

Practice Considerate Snow and Ice Removal

During our Canadian Winters, removing snow and ice from your driveway is essential. However, common methods like snow plows and rock salt can harm your concrete driveway.

Opt for a snow blower for snow removal, taking care not to scrape the concrete surface. For compact snow or ice, use a plastic shovel instead of metal to prevent scratches or damage to the driveway.

Avoid using salt or chemical de-icers as they can deteriorate concrete, especially in its first winter. Instead, use sand or cat litter for traction without damaging your driveway.

Wise Parking Practices

Even though concrete is tough, it's not indestructible. How and where you park your vehicle can significantly impact the longevity of your concrete driveway. Excessive weight on the driveway's edges, the weakest points, can lead to cracks and require costly repairs.

Always try to park away from the edges and ensure heavy vehicles do the same. Moreover, avoid spinning your wheels to prevent tire marks, which can diminish your driveway's appearance.

Maintain Cleanliness with Pressure Cleaning

Regular cleaning is key to maintaining your driveway. Dirt and debris can embed in the concrete and lead to discolouration and staining. Utilize an effective cleaning agent such as Sodium Hypochlorite in addition to a pressure washer with a surface cleaner attachment to keep it looking pristine and to help prevent damage.

Address spills, especially from oil, gas, and grease, promptly to avoid permanent staining, even on sealed concrete. Absorb spills with sawdust or cat litter, then sweep it up and clean any remaining stains with eco-friendly, grease-cutting detergents.

Key Points to Remember:

Maintaining a concrete driveway is straightforward with the right approach. Sealing the concrete, careful snow and ice removal, smart parking, and regular cleaning will ensure your investment remains in excellent condition for many years.

Common Concrete Sealer Problems

Dealing with issues related to concrete sealers is often a challenge for homeowners, particularly when the final appearance or functionality falls short of expectations. Typically, these issues stem from either applying too much sealer, using it under less than ideal conditions, or accumulating multiple layers over time. Here, we explore some of the common problems encountered with concrete sealers, their causes, and strategies for prevention.

Formation of Bubbles in Sealer

Bubbling in a concrete sealer is often the result of applying the sealer too thickly. The process of outgassing, or the release of air from the concrete, requires the ability to pass swiftly through a thin layer of wet sealer. Ideally, a single coat of an acrylic concrete sealer applied at a standard rate of 300 square feet per gallon should measure approximately 5 mils in wet thickness, reducing to about 2 mils once dried. Over-application impedes the escape of air, leading to bubble formation. Moreover, bubbling can occur if the sealer is applied during hot conditions or on concrete exposed to direct sunlight, causing the sealer to dry prematurely on the surface and trap solvent beneath, which then tries to escape and forms bubbles. To mitigate this, it's advisable to apply sealer in cooler conditions and away from direct sunlight.

Solvent-Based Sealer Whitening, Peeling or Flaking

Whitening, or "blushing," of a solvent-based sealer can result from applying it to a wet surface or freshly laid concrete that hasn't fully cured. This prevents the sealer from adequately bonding to the concrete surface, causing it to sit atop a layer of water. Additionally, applying thick layers of sealer or reapplying it multiple times over the years can trap moisture beneath, leading to loss of adhesion and a whitened appearance as the moisture and air beneath the sealer alter its appearance. To prevent this, adhere strictly to the manufacturer's guidelines on application rates and coat numbers.

Lap lines and Roller Marks

A common mistake by amateur applicators is failure to keep a wet edge. Due to the short curing time of film forming sealers, it is imperative that the working area be kept wet and a proper feathering technique used. This is especially important in instances where a film forming sealer is used on a porous surface such as concrete with a brushed finish. Using a sprayer with a fan-tipped nozzle greatly improves results when combined with a sweeping and consistent feathering technique.

Concrete Appears Dark or Uneven in Color Post-Sealer Application

Acrylic sealers tend to darken concrete and impart a glossy, "wet look" finish, which can make the concrete's inherent color and texture variations more pronounced. Factors such as the concrete mix design, use of additives, finishing techniques, and porosity can influence the final appearance. To avoid unwanted color changes, opt for a penetrating water repellent sealer or conduct a small test area with a film-forming sealer to ensure the resulting color change is within acceptable limits.