How to remove polymeric sand haze from pavers

Polymeric sand haze is a thin film of sand dust and binder that set on the face of the pavers instead of in the joints. To remove polymeric sand from pavers once it has set, let the new joints cure for at least 30 days, then scrub it off with a weak paver haze or efflorescence cleaner on a dry day between 10°C and 30°C, or strip it with a hot pressure washer. Light haze can weather away with rain.

If the film is spread across a whole driveway, or you’d rather not handle acid cleaners, have a look at our interlock cleaning and sealing service.

What causes the white haze?

The haze is polymer that was activated on the paver surface. Techniseal’s data sheet for its RG+ sand explains it plainly: if the pavers are damp, the moisture activates the polymer, which makes sand stick to the surface and stain it.

Alliance Gator names the same causes: high humidity, damp pavers, and a surface that wasn’t cleaned properly before watering. Techniseal also warns against flooding the surface when you water the sand in.

In practice it usually traces back to one of these:

• Sweeping sand onto pavers that were still wet from rain, dew or a morning hose-down.
• Skipping the leaf blower, or blowing too lightly, so fine dust stayed in the texture of the pavers.
• Watering with a hard stream instead of a gentle shower, so sandy water splashed across the surface.
• Installing on a humid, still day when the surface never fully dried.

Deeply textured pavers hold the most dust. Unilock says even careful work can leave a residue that looks like a film on them. If you see buildup, it says to stop, let the surface dry and brush it off before wetting.

Is it haze or efflorescence?

If the film showed up right after the sand job and sits heaviest near the joints, it’s probably haze. A powdery white bloom across the paver faces is more likely efflorescence.

Efflorescence is a white, powdery salt deposit that comes up out of the concrete itself. Unilock calls it naturally occurring calcium salts, and Alliance Gator says it often disappears on its own, usually after the first year.

Alliance Gator even says a white haze on pavers is most likely efflorescence. Polymer haze is different: it’s leftover sand and binder from the install, sitting on top.

You can have both at once. Alliance Gator notes that wetting the pavers to activate the sand can itself bring up efflorescence, and says its efflorescence cleaner should remove either one.

How do you remove polymeric sand haze from pavers?

Use a diluted paver haze or efflorescence cleaner, or strip the haze with a hot pressure washer. Alliance Gator names both for its sands, and says bad cases may need repeat applications. Techniseal also sells a separate product, Paver Restorer, that it lists for haze left by some polymeric sands.

Using a cleaner

A paver haze or efflorescence cleaner is the practical choice for most homeowners. Unilock notes that these cleaners are typically acid-based, and they’re used heavily diluted.

Techniseal’s data sheets for Paver Restorer and Pre-Seal Cleaner give the same directions: 1 part product to 4 or more parts water, never full strength. The numbered steps further down follow those sheets. Read your own product’s label, because ratios and surface limits vary by brand.

Using hot water

A hot pressure washer works by heat, not force. Alliance Gator says water at 82°C (180°F) or hotter reactivates the polymer so set sand can be stripped away, and suggests boiling water for a smaller area.

Since the heat is what reactivates the polymer, an ordinary cold-water washer can’t do the same thing.

Before you start

• Techniseal’s Pre-Seal Cleaner is for concrete only. Check what your surface is first.
• Unilock warns that acid cleaners can slightly change paver colour. Techniseal suggests starting at 1:8 on very light and very dark pavers.
• Protect plants, cars and the lawn from splash and drift. Techniseal’s sheets also ask you to check your municipality’s rules on runoff before rinsing cleaner toward the street or a storm drain.

When can you clean it in Ontario?

Wait until the joints have fully hardened, then pick a mild, dry stretch. Techniseal’s EZSAND sheet recommends waiting at least 30 days after installation before cleaning or sealing, and restricts pressure washers in that first month.

Techniseal’s haze and efflorescence cleaners need a dry surface that’s warm to the touch and a temperature between 10°C and 30°C. The Paver Restorer sheet adds: not under blazing sun.

Around Markham, that makes May to September the easy window. Environment Canada’s 1981–2010 normals for the Buttonville station in Markham give these average daily highs:

In spring and fall, pick a mild afternoon. In midsummer, clean in the morning before the pavers get hot.

If your sand went in during late fall, it’s usually better to leave the haze through winter and clean in spring than to scrub on a day below the label’s 10°C minimum. Rain over the winter may fade some of it in the meantime.

Mistakes that make haze worse

• Scrubbing before the joints have hardened and pulling fresh sand out with the haze.
• Using a cleaner full strength. Techniseal is clear that its products can damage the pavers if they aren’t diluted.
• Letting cleaner dry on the surface. Techniseal says to keep it wet until it’s rinsed off.
• Reaching for muriatic acid. Techniseal sells its paver cleaners as muriatic-free so they don’t damage the surface.
• Sealing over haze or efflorescence to hide it. The film gets trapped under the sealer.
• Blasting the joints with a narrow pressure-washer tip, which can empty them and mean re-sanding.

How to avoid haze next time

Keep the pavers dry and free of dust before any water touches the sand. The order matters:

1. Install on dry pavers, never after rain, dew or a hose-down.
2. Sweep the sand into the joints, then blow the surface until no dust rises.
3. Water gently in sections, with a shower setting rather than a jet.

Our guide on how to apply polymeric sand covers the full sequence. The polymeric sand guide explains how long joints last and when they need replacing.

When it’s worth calling someone

A small patio with light haze is a reasonable Saturday job with a jug of paver cleaner and a street broom. It’s worth getting help when:

• the haze covers a whole driveway
• you can’t tell if it’s haze, efflorescence or both
• the pavers are natural stone
• the joints have washed out and need redoing anyway

Cleaning, re-sanding and sealing usually belong in the same plan, in that order.

We work across Markham and nearby towns such as Richmond Hill. If you want us to look at yours, call or text (437) 684-2535, or see what our interlock cleaning and sealing service covers.

You can also read how to clean interlock without damaging it and whether to seal your interlock before deciding.