How to Seal Pavers Step by Step

Why seal pavers

Most pavers on driveways, paths and terraces are made of concrete. Concrete is porous, so water gets in, and with the water come dirt, grease, oil and algae spores. An unprotected surface darkens over time, green deposits appear in shaded spots and moss grows between the pavers. This happens slowly, so it is easy to miss until the difference becomes clearly visible.

Water in winter is a separate issue. Water that has penetrated the structure freezes and breaks the material from the inside. After a few seasons you see this on edges and corners that start to crumble. Sealing limits water absorption and therefore the amount of water that can freeze inside the stone.

A protective product does not mean the pavers will never get dirty and never need cleaning. It changes two things. First, water and dirt get in more slowly, so routine cleaning is faster. Second, the surface ages more slowly and keeps its colour longer.

Paver types and the right protection

Before you choose a product, look at what you are dealing with, because absorbency and appearance vary a lot.

• Plain concrete pavers absorb the most and benefit the most from sealing. They are the first to turn green and get dirty in the joints.
• Washed and finished concrete pavers show the aggregate and look more decorative, but often absorb even more in the top layer.
• Natural stone, for example granite, has a different structure and different expectations for appearance. A test is especially worthwhile here, because stone reacts differently.
• Clinker is hard and low absorbing, yet the joints still collect dirt and green deposits.

Impregnation or coating, which effect you want

This is the first real decision, and you should make it deliberately, because the two product groups work differently and give a different look.

• A penetrating impregnation sinks into the structure and protects from the inside. It does not form a visible layer, so the surface stays matt and natural. A good choice when you want protection without changing the look.
• A coating forms a thin film on the surface. It often deepens the colour and creates the so called wet look, while also acting as an extra barrier. People choose it when they want to emphasise the colour.

When to seal pavers

Weather matters here more than you might think, and it often decides the success of the whole job. The product goes onto a dry surface, in temperatures above freezing and when no rain is forecast for the next few hours. You will find the exact temperature range and the time after which the surface is water resistant on the label of the specific product.

Avoid working in full sun and heat. A heated stone makes the product evaporate before it can sink in, and then the protection is shallow and uneven. For the same reason, morning and afternoon hours are better than midday.

What to prepare before you start

Good preparation shortens the work itself and improves the result. Gather everything before you begin, so you do not interrupt the application halfway.

• A brush or broom to remove loose dirt and weeds from the joints.
• A paver cleaner for stains, deposits and green growth.
• Water, a garden hose or a pressure washer on a moderate setting.
• A roller, brush or garden sprayer for applying, depending on the size of the area.
• A protective product matched to the effect you want, impregnation or coating.
• Gloves and goggles, plus any protective equipment stated on the product data sheet.
• Tape and film to cover spots that should not get any product.

How to check whether the pavers are ready

Two things decide whether you can start, namely cleanliness and dryness. The pavers must be free of dirt, deposits and loose particles, because each of these will be sealed underneath the product. They must also be dry not only on top but just below the surface.

You can judge cleanliness by sight and touch. If dust remains after running your hand over them, or you see greasy stains, the surface is not ready yet. Dryness is easiest to check after rain. If the joints are darker than the rest, there is still water in the stone and you need to wait.

Sealing pavers step by step

1. 1
   Remove weeds and loose dirt. Clear weeds and moss from the joints and sweep away sand and leaves. The less loose dirt, the more evenly the cleaner works and the less you use.
2. 2
   Clean the surface. Apply the paver cleaner and remove stains, deposits and green growth. If you use a pressure washer, stay moderate. Too strong a jet washes sand out of the joints and can damage the surface of the pavers.
3. 3
   Top up the sand in the joints if needed. After thorough cleaning some sand is usually missing. It is worth topping up the joints and letting them dry, because they keep the pavers in one plane.
4. 4
   Let the pavers dry thoroughly. This is the step people shorten most often, and they should not. The surface must be dry just below the top layer too. Drying time depends on the weather, so wait longer rather than too short.
5. 5
   Do a test. Apply the product to a small, inconspicuous area. You will check the final effect and get a feel for the consumption, without risking the whole surface.
6. 6
   Apply the product evenly. Work with a roller, brush or sprayer so that the product covers the whole surface, without puddles and missed spots. Spread it as you go and do not let it dry in low spots.
7. 7
   Apply a second coat if needed. Absorbent or old pavers often need two coats. The number of coats and the interval between them is given on the product label.
8. 8
   Protect the fresh surface. Let the product bond with the base before you allow foot or vehicle traffic on the pavers. The time after which the surface is ready for use is also on the product data sheet.

Difficult stains and how to deal with them

Ordinary dirt comes off with normal cleaning, but a few types of stain need a separate approach. It is best to deal with them before sealing, because the protective product does not remove dirt, it seals it in.

• Oil and grease stains on the driveway. The sooner you notice them, the easier they are to remove. Use grease dissolving products according to their instructions.
• Rust, for example from metal furniture or tools, is a separate type of stain that needs a dedicated product.
• Efflorescence, a whitish deposit that can appear on new pavers. This is a natural process in concrete. There are products that help reduce it, and some of it disappears on its own over time.
• Moss and algae in the joints return as long as moisture remains. That is why limiting water absorption through sealing is all the more important after removing them.

The most common mistakes to avoid

• Applying to dirty pavers. The product seals the dirt in and the result is worse than if you had done nothing.
• Working on a damp base. Water in the structure stops the product reaching where it should.
• Too thick a coat at once. The excess does not sink in, it just forms sticky streaks and stains.
• Skipping the test. The wet look does not suit everyone, and it is hard to undo on the whole surface.
• Applying just before rain. The product needs time to bond with the base.

How much product to buy

Consumption depends on how absorbent your pavers are and whether you apply one coat or two. An old, porous surface takes more than a smooth, new one, and washed stone with exposed aggregate often more than plain stone.

Instead of guessing, use the consumption calculator available with every product in our shop. You enter the area in square metres and the calculator converts it into the number of litres needed. The coverage of the pack is also on the product data sheet. If you plan two coats, take that into account when buying.

How to care for pavers after sealing

Sealed pavers are easier to maintain, but they still need basic care. Sweep away sand and leaves, because lying dirt holds moisture. Rinse off everyday dirt with water.

When you notice that water no longer beads on the surface and soaks in as it did before sealing, that is the signal to refresh the protection. How quickly this happens depends on the product, the paver type and how much the surface is used, so you will find the durability on the data sheet of the specific product. Refreshing is usually simpler than the first sealing, because the surface is already in good condition.

Short glossary

• Penetrating impregnation. A product that sinks into the material structure and protects from the inside, without forming a visible layer.
• Coating. A product that forms a thin film on the surface and often deepens the colour.
• Hydrophobing. Giving the surface water repelling properties, so that water runs off instead of soaking in.
• Wet look. An appearance where the pavers look slightly damp, with a stronger, deeper colour.
• Efflorescence. A whitish deposit that sometimes appears on concrete, linked to natural processes in the material.