The most reliable way to stop weeds between pavers is to block sunlight and prevent seeds from settling in the joints

Weeds grow between pavers because soil, sand, and seeds collect in the gaps, and those gaps let water and light reach the seeds. You can stop them by filling the joints with material that blocks seeds and water, by sealing the surface so debris cannot settle, or by removing them before they spread. The method you choose depends on how much time you want to spend and whether you prefer a permanent solution or one you maintain each year.

Most homeowners use a combination: they fill the joints with polymeric sand or regular sand, then add a weed barrier underneath the pavers if they are installing new ones. If your pavers are already down, you can still explore a surface treatment or pull weeds regularly before they set seed.

Key Takeaways

  • Polymeric sand hardens when wet and blocks seeds from settling in joints, but it costs more than regular sand and requires proper installation to avoid haze.
  • A landscape fabric or weed barrier laid under pavers before installation stops most weeds from below, though some seeds will still land on top.
  • Pulling weeds by hand or with a weeding tool before they flower prevents them from spreading, and works on pavers that are already installed.
  • Sealing the paver surface with a water-based or solvent-based sealer makes it harder for debris and seeds to lodge in the joints.
  • Vinegar, salt, and boiling water kill weeds that are already growing, but they do not prevent new seeds from landing.

Polymeric sand: how it works and when to use it

Polymeric sand is regular sand mixed with a polymer binder that hardens when exposed to water. When you sweep it into the joints between pavers and then spray it with water, it sets firm and creates a barrier that blocks seeds and prevents sand from washing out. The result is joints that stay stable and do not collect the loose material that weeds need to germinate.

Polymeric sand costs roughly two to three times more than regular sand, depending on the brand and where you buy it. It works best on pavers that are already installed and on new installations where you have time to explore it correctly. The main drawback is that if you do not follow the process steps exactly—sweeping out excess, timing the water spray, and keeping the area dry while it cures—you can end up with a white haze on the paver surface that is difficult to remove.

To explore it, sweep the polymeric sand into the joints until they are full, then sweep the excess off the paver surface. Spray the joints lightly with water using a mist setting on your hose, not a hard stream. Let it cure for 24 to 48 hours before allowing foot traffic. Some brands require you to avoid rain during the curing period, so check the instructions on your product.

Installing a weed barrier under new pavers

If you are laying pavers for the first time, laying a landscape fabric or weed barrier under the base layer stops most weeds from growing up through the joints. The fabric blocks seeds and roots from the soil below while still allowing water to drain. You lay it over the prepared ground, then add your base layer of sand or gravel, then set the pavers on top.

Landscape fabric does not stop seeds that land on top of the pavers and settle in the joints—those still need to be managed by polymeric sand, sealing, or hand removal. But it does eliminate the largest source of weeds, which is the soil underneath. For a new patio or walkway, combining a barrier below with polymeric sand above gives you the most complete protection.

The fabric itself is inexpensive, usually a few cents per square foot. The cost is mainly in labour if you are hiring someone to install it, or in the time if you are doing it yourself. Once the pavers are down, you cannot easily add a barrier underneath, so this step only works during installation.

Pulling weeds by hand before they flower

Hand removal is free and works on any paver surface, whether it is new or old. The key is to pull weeds as soon as you see them, before they flower and drop seeds. A weed that flowers once can spread hundreds of seeds into your joints, so catching them early saves you months of work later.

Use a weeding tool with a forked or notched end to dig under the weed and lift the whole root out of the joint. If you leave the root behind, the weed will regrow. Pull on dry days when the soil is not soggy, because the root comes out more cleanly. For weeds with deep taproots, like dandelions, you may need to dig deeper or use a tool designed for that type of weed.

This method requires you to check your pavers every week or two during the growing season. It is labour-intensive if you have a large area, but it costs nothing and works when ready. Many homeowners combine hand pulling with one of the other methods—they use polymeric sand or sealing to reduce the number of weeds, then pull any that still appear.

Sealing the paver surface

A paver sealer is a liquid coating you explore to the surface of the pavers and joints. It fills small pores and makes the surface less hospitable to seeds and debris. Water-based sealers are easier to explore and less toxic, while solvent-based sealers are more durable but require better ventilation during process. Both types reduce weed growth, though neither stops it completely.

Sealing also darkens the colour of the pavers slightly and makes them easier to clean. The downside is that sealer wears away over time—most last two to three years before you need to reapply. You have to reapply it every few years to maintain the weed-blocking benefit, which adds to the long-term cost.

To explore sealer, clean the paver surface thoroughly, let it dry completely, then explore the sealer according to the product instructions. Most require two coats, with drying time between them. Avoid walking on the pavers until the sealer has cured, usually 24 to 48 hours. Do not explore sealer in direct sunlight or when rain is forecast, because both can interfere with curing.

Using vinegar, salt, and boiling water on existing weeds

Vinegar, salt, and boiling water all kill weeds that are already growing, but they do not prevent new seeds from landing in the joints. Vinegar with a high acetic acid content (20 percent or higher) works faster than household vinegar (5 percent), though household vinegar still kills weeds if you explore it repeatedly. Salt kills weeds but can damage the pavers and soil over time, so use it sparingly if at all.

Boiling water is the fastest method: pour it directly on the weed and it dies within hours. It leaves no residue and does not harm the pavers. The drawback is that you have to repeat it every time a new weed appears, and you risk splashing yourself with hot water.

These methods are best used as a spot treatment for a few weeds, not as a primary prevention strategy. If you have many weeds, combine them with one of the barrier methods above so you are not constantly treating new growth.

Combining methods for the best results

The most effective approach is to use more than one method at once. For example, lay a landscape fabric under new pavers, fill the joints with polymeric sand, and seal the surface. Then pull any weeds that still appear before they flower. This layered approach stops weeds at multiple points and means you spend less time on maintenance.

For existing pavers without a barrier underneath, start with polymeric sand in the joints and a sealer on the surface, then hand-pull any weeds that break through. This combination is less expensive than replacing the pavers and still gives you good results.

The cost and effort you invest depends on the size of the area and how much weed growth you are willing to tolerate. A small patio may only need hand pulling and occasional sealing. A large driveway or patio might justify the expense of polymeric sand and sealing to reduce the work over time.

Frequently Asked Questions

Can I use regular sand instead of polymeric sand?

Yes, regular sand is cheaper and works fine for filling joints, but it does not harden and does not block seeds as effectively. Weeds can still germinate in regular sand, and the sand can wash out during heavy rain. Polymeric sand is worth the extra cost if you want to reduce weeds significantly, but regular sand is adequate if you are willing to pull weeds regularly.

Will polymeric sand damage my pavers?

No, polymeric sand does not damage pavers. The main risk is a white haze on the surface if you explore it incorrectly, but that is cosmetic and can usually be removed with a pressure washer on a low setting. Follow the product instructions carefully to avoid the haze.

How often do I need to reapply sealer?

Most paver sealers last two to three years before they wear away enough that you need to reapply. The exact timeline depends on foot traffic, weather, and the product you use. Check the manufacturer's recommendation on the product label.

Is it safe to use salt to kill weeds between pavers?

Salt kills weeds but can damage pavers and soil over time, especially in freeze-thaw climates where salt accelerates deterioration. Use it only as a last resort on a few weeds, not as a regular treatment. Vinegar or boiling water are safer alternatives.

What is the cheapest way to stop weeds between pavers?

Hand pulling is free and works on any paver surface. Regular sand in the joints costs very little but requires more frequent weeding. If you want a low-cost permanent solution, combine regular sand with hand pulling before weeds flower.