How to Clean Pavers Before Sealing: A Step-by-Step Prep Guide

Pressure washing a Colorado paver walkway

To clean pavers before sealing, fix damaged units, remove stains first, wash the whole surface with a wide, low-angle spray, treat efflorescence with a buffered remover, rinse well, and let everything dry for at least 24 hours. Sealer locks in whatever is on the surface. Dirt, algae, oil and white mineral haze all end up under the film, so the cleaning decides how the finished job looks.

This guide walks through the whole prep in the order a crew would do it, with the pressure numbers, drying times and joint-sand decisions that trip people up. We work on driveways, patios and commercial lots along the Front Range, so we also cover what Colorado weather does to your timing.

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TL;DR

  • Order matters: repair or replace damaged pavers, spot-treat stains, then clean the whole surface, then deal with efflorescence and joint sand.
  • Keep pressure moderate. Professional guidance describes a wide spray at a low angle, and one manufacturer’s 2026 U.S. guide suggests about 1,500 psi at 12 to 18 inches.
  • Remove efflorescence with a proprietary buffered remover, following the supplier’s dilution, and test on a small area first.
  • Wait at least 24 hours of dry weather after cleaning, and longer if anything looks or feels damp. Follow the sealer’s label.
  • Decide on joint sand after cleaning and before sealing: washed-out joints should be refilled and stabilized.

Table of Contents

Why cleaning comes before sealing

A sealer is a coating or penetrating treatment applied to a surface that has to be bare and dry. If dirt, oil or algae remain, the sealer bonds to them instead of the paver. You may see blotches, cloudiness or peeling a season later, and the only fix is stripping and starting over.

The Concrete Masonry & Hardscapes Association (CMHA) says that before sealing you should remove dirt, oil stains and efflorescence, and let the surface dry for at least 24 hours with no moisture or surface dampness. Everything below builds on that sequence.

It also helps to know what sealing can and cannot do. Sealing does not hide stains, and it does not cure efflorescence. It deepens color, makes future cleaning easier and helps stabilize joint sand, but only over a clean base.

Step 1: Inspect the pavement and fix problems first

Walk the whole area before you pick up a hose. Look for:

  • Cracked or broken units. CMHA recommends replacing cracked or broken pavers before you clean and seal.
  • Settled or tilted areas. Washing and sealing will not level a low spot, and standing water in a dip stresses any sealer.
  • Weeds and deep roots. Pull them with the root if you can. Weeds left in the joints regrow through new sand.
  • Drainage. Note where water runs off. You will need to manage runoff while cleaning, and you want to know where the wash water ends up.

If you are in Colorado, add freeze-thaw to the list. Pavers that heaved over winter, or joints that opened up, are easier to correct before sealing than after.

Step 2: Treat stains before you clean the whole surface

CMHA’s guidance is to remove stains first, then clean the whole pavement. That order keeps you from spreading oil or rust across clean pavers and then sealing it in.

What you are likely to find:

  • Oil and grease near garage doors and parking spots. Fresh spills lift more easily than old ones, so treat them early.
  • Rust from furniture legs, fertilizer or sprinklers.
  • Organic stains from leaves, berries and pet waste.
  • Algae, moss and mildew on shaded or damp areas, which show as green or black films.

Use a cleaner made for the stain type and for concrete pavers. Follow the dilution and application directions on the label. Test any cleaner on a small hidden area first: CMHA notes that strong acids can slightly change paver color, and recommends protective clothing and goggles when you use acidic solutions.

Protect the lawn and plant beds around the work. Wet them down before you apply a cleaner and rinse them afterward, and keep chemical runoff away from storm drains and garden soil.

Step 3: Wash the whole surface the right way

Once the stains are handled, you clean the whole surface to remove dirt, algae and loose debris. A hose and a stiff broom can handle lightly soiled pavers. Large or heavily soiled areas are where pressure washing earns its keep.

Pressure, angle and distance

More pressure is not better. Excess pressure scars the paver face and blasts out joint sand. Two checked sources give useful ranges:

Source Pressure Technique
CMHA technical guidance Professional high-pressure cleaning of roughly 1,000 to 4,000 psi at 2 to 6 gallons per minute Wide spray, low angle, to reduce removal of joint sand
Techniseal 2026 U.S. restoration guide About 1,500 psi 45-degree angle, wand held 12 to 18 inches away, work in controlled sections from high to low elevation

The wide range in the CMHA figure reflects professional equipment and judgment: flow rate, nozzle and distance matter as much as the psi on the gauge. For a homeowner’s machine, start at the gentle end, keep the wand moving and test in a corner. If you see lines, swirls or a roughened surface, back off.

Work from the high side of the surface toward the low side so dirty water does not run over finished pavers. Overlap passes evenly. Stripes in a cleaned surface are the number one visible mistake, and they show up even more once a sealer deepens the color.

Surface cleaners versus a bare wand

A rotary surface cleaner holds the spray at a constant height over the pavers, which gives a more even result than freehand wand work on big flat areas. A wand is still useful at edges, steps and tight corners. Pros often combine both.

Surface cleaner and wand uses on pavers

Algae, moss and weeds

Green films and moss respond to a biological cleaner or a suitable algae treatment applied before washing, so the rinse removes what the treatment loosened. Always follow the product’s label, and wet and rinse nearby plants. Moss growing in the joints can be scraped out carefully with a screwdriver or similar tool without gouging the paver, as one hardscape guide on moss, weeds and algae describes. Heavy coverage is better handled with a surface cleaner.

Moss and weeds growing between pavers

Step 4: Remove efflorescence

If your pavers have a whitish, chalky haze, that is probably efflorescence. CMHA explains that it is moisture carrying calcium compounds to the concrete surface, where they dry as a white deposit. It is common on new pavers and can appear on older ones after wet spells.

Sealing over efflorescence is a mistake. It traps the haze, and more can form under the sealer.

  1. Use a proprietary buffered efflorescence remover made for concrete pavers. Mix and apply it exactly as the supplier directs.
  2. Test on a small area first, and wear gloves, protective clothing and goggles.
  3. Scrub and rinse thoroughly. Do not let the product dry on the surface.
  4. Let the area dry for at least 24 hours and check the result in daylight. A damp paver can look clean and show haze when it dries.
  5. Repeat if needed. CMHA notes that severe deposits may need a second treatment, and that you should consult the product manufacturer.

If the haze comes back quickly, there is likely a moisture source, such as poor drainage, a downspout dumping onto the patio or irrigation spray. Fix that before sealing or the problem returns.

Step 5: Decide what to do with the joint sand

After cleaning, check the joints. Pressure washing often removes some sand, and old sand may be contaminated with algae spores and seeds. Joints should be full before you seal, because sealer is meant to work with stable, filled joints.

Your options:

  • Joints still full and firm: leave them and move on to drying.
  • Joints partly washed out: refill with joint sand suited to the joint width, sweep it in, compact it and clean every grain off the surface.
  • Joints need stabilizing: polymeric sand binds the sand into a firmer joint. A sand-product maker’s guide for applying polymeric sand to an existing patio notes that plain sand tends to wash out after heavy rains and weeds can push through.

If you do use polymeric sand, the details decide whether it works:

  • Surface dust causes haze. One landscaper’s guide warns that polymeric sand can leave haze if pavers are damp or dust remains on them.
  • Water control matters. Joints can wash out if they are not fully filled or compacted or are over-watered, and they can stay soft if too little or too much water is used or rain arrives before curing.
  • Check the weather. Techniseal’s guidance for its system calls for temperatures above 32°F for the following 24 to 48 hours, and says the installation must be completely dry before new jointing product goes in. In Colorado that rules out many cold-snap days in fall and spring.

There are tradeoffs to understand when you choose a joint product. Homeowner guidance lists cracking in severe freeze-thaw, hard removal when pavers must be reset, and staining if residue is left as issues. They point to the same lesson: joint depth, compaction, residue removal and curing conditions drive the outcome, so follow the product’s instructions closely.

Step 6: Rinse and let the pavers dry

Rinse everything again after cleaning products and sweeping, so no film or residue is left. Then wait.

How long? The floor is at least 24 hours without moisture or surface dampness per CMHA. Several ranking pages say 24 to 48 hours. In practice, drying time depends on weather, humidity, airflow, paver type and how much water you used. One manufacturer’s blog says that if pavers still look or feel damp, wait longer and follow the specific sealer’s instructions.

Some practical checks:

  • Look at color. Pavers should be uniform, with no darker patches.
  • Check the joints. Sand holds water longer than the paver face, and trapped moisture can cloud a sealer.
  • Check the forecast. Dew, sprinklers and rain all reset the clock. Turn off irrigation zones that spray the area.
  • Read the sealer label for minimum and maximum temperatures. Late fall and winter in Colorado are often too cold or too damp for a safe window.

A prep checklist you can print

Step What to do Done when
1 Inspect, replace cracked units, pull weeds, note drainage No loose, broken or sunken pavers
2 Treat oil, rust and organic stains Stains lifted or reduced, area rinsed
3 Wash the whole surface at moderate pressure, wide spray, low angle Even color, no wand marks, debris gone
4 Treat efflorescence with a buffered remover No white haze after drying
5 Refill and compact joints if needed, sweep clean Joints full, surface free of sand dust
6 Rinse and dry at least 24 hours, longer if damp Pavers and joints dry to the touch

Our perspective on paver prep

Most paver sealing problems we hear about start long before the sealer comes out. Someone skips the stain step, or washes too hard and blows out the joints, or seals a patio that still feels cool and damp.

At All Day Power Washing, we use commercial-grade equipment and insured crews, and we treat cleaning as a controlled process, not a blast of water. Pressure, nozzle, distance and pace change from one surface to the next, and an even, consistent wash is what makes the finished color look right.

We would rather you start with a properly cleaned surface than a quick rinse. If you want that stage handled for your driveway, patio or commercial lot, we offer same-week quotes in Colorado Springs and the Denver metro area, and we stand behind our work with a satisfaction guarantee that includes return visits if needed.

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Get the cleaning done by a crew

If your pavers are large, heavily stained or stubborn, a professional wash saves time and avoids the risk of scarring the surface. All Day Power Washing handles driveways, concrete and commercial lots for homeowners and property managers in Colorado Springs and the Denver metro area. Our crews are fully insured and we give same-week quotes.

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Tell us about the area, the stains you see and your timeline, and request a quote for power washing and concrete cleaning. We do not publish fixed prices because each job depends on size, condition and access.

Colorado timing: when to clean and seal

Front Range weather swings from hot, dry days to cold nights, even in shoulder seasons. That affects every step above.

  • Pick a stretch of dry days. You need time to wash, dry and then seal, so look for several days in a row with low humidity and no rain.
  • Watch overnight lows. The Techniseal guidance for jointing products calls for above-freezing temperatures for the 24 to 48 hours after installation. Plan around cold nights.
  • Shade dries slower. North-facing patios and areas under eaves may need extra time.
  • Sprinklers matter. Overspray from lawn irrigation can wet joints without you noticing.

If a good window is not available, wait. Sealing in poor conditions is the most common reason for cloudy or peeling results.

FAQ

Can I just use soap and water to clean pavers before sealing?

For pavers that are installed recently and only lightly dirty, a mild detergent, scrub brush and thorough rinse may be enough. Oil, algae, rust and efflorescence need targeted treatment first. Always test a cleaner on a small area, and let the pavers dry before sealing.

How long should pavers dry before sealing?

At least 24 hours with no moisture or surface dampness, according to CMHA guidance. Humid, cool or shaded conditions can take longer, so check that the surface and joints are dry and follow the sealer label.

Do I need to refill the joints after cleaning?

If the cleaning removed sand and the joints are no longer full, yes. Refill and compact them, then sweep the surface clean of any dust or residue. Joint product instructions on temperature and water must be followed closely.

How do I remove white haze from pavers?

That haze is usually efflorescence. Use a proprietary buffered remover at the supplier’s dilution, scrub, rinse, and let the pavers dry for 24 hours to judge the result. Severe cases may need a second treatment.

What pressure is safe for pavers?

Keep it moderate and use a wide spray at a low angle. Techniseal’s 2026 guide suggests about 1,500 psi at 12 to 18 inches, while CMHA describes professional work in a broader range. Test in a hidden corner first.

Sources