What are the components of an interlocking concrete pavement?

The components include a base, bedding sand, concrete pavers with sand in their joints, and an edge restraint to contain the pavers at the perimeter.

What is the base made of? what kind should be used?

The base is typically made of compacted, crushed stone that varies in size from one inch (25 mm) down to dust. Base materials used under asphalt street pavements are acceptable for use with interlocking concrete pavements. Some parts of the country use cement stabilized or concrete bases due to very weak or slow draining soils. However, most applications use a crushed stone base that's compacted.

What is drive grid system? What does it do? Is it necessary?

Sometimes called filter fabric, Drive Grid System is made of plastic threads that allow water to pass around them, but not very small particles of soil beneath them. Drive Grid System separates and contains the base from the underlying soil subgrade. It allows the base to shed water, and prevents the soil around it from working its way into the base. Without Drive Grid System, the soil will work its way into the base and weaken it. This is a slow process that happens when the soil is saturated with water or during periods of thawing. Drive Grid System stops this process and extends the life of the base by many years. Drive Grid System is recommended for use over silt and clay soils. It is not essential in sandy soils.

Is it okay to use fabric designed to prevent weed growth in planting beds instead of drive grid system?

No, this material is sometimes not as strong as Drive Grid System and can tear easily.

Should limestone screenings or stone dust be used under the concrete pavers? What is recommended by ICPI?

No. Most screenings and stone dust have too many fine particles that slow drainage and rut under repeated loads from tires. Sand made with crushed shells (common in Florida) shouldn't be used either. Concrete sand is recommended. It's the same sand mixed into concrete pavers and poured, cast-in-place concrete.

What is interlock?

In short, it's the inability of a paver to move independently of its neighbors. It's the locking of the pavers that causes loads to be spread over a wider area of pavers than where the load was applied. It's the key to the strength of the pavement system.

Should I seal concrete pavers?

Sealing is not essential in many applications but it offers some benefits like making spills and stains easier to remove. Liquid sealers are applied after the pavers are installed and are cleaned. Paver suppliers can recommend cleaners for concrete pavers. Once applied, the sealers soak into the concrete and into the joints. The sealers in the joints help keep the joint sand in place and prevent weeds and ants, and sealers are essential for areas around swimming pools.

Are there disadvantages to sealing?

Since they are a transparent paint-like coating, sealers generally need to be reapplied every three to five years. Use sealers specifically for concrete pavers. More intense use of the pavers and extreme climates often increase the need for re-applying a coat of sealer.

How do I remove stains and fix damaged pavers?

If the stain is one one or two pavers, replacing them with new pavers is the easiest way. Depending on the paver, some can be flipped over rather than replaced. Many suppliers of concrete pavers offer cleaners especially made for removing stains and for overall cleaning of the surface.

Will de-icing salts damage my pavers?

No. High density concrete pavers are formulated to resist deterioration from de-icing salts that are applied at the proper application rates.

Will snow plows damage or dislodge my pavers?

No. Properly installed pavers fit tightly together and form a uniform surface that presents no problem for plows, snow blowers, and shovels.

Is it ok to use stone dust for a bedding layer under pavers?

No. Stone dust traps water and gets spongy, which can cause rutting and settlement. Use coarse concrete sand or stone sand that conforms to ASTM C-33.

Do I need a concrete footing to support my segmental landscape wall?

No. Unless the soil is extremely weak, a firmly compacted gravel footing is sufficient to support the wall and possesses the ability to accommodate natural movement of the wall.

If a paver gets broken or damaged, can it be replaced?

Yes. We recommend that you save a few pavers from your initial installation, just in case you need to replace one or two.

Can I use gravel behind my wall instead of 3/4" crushed stone?

No. It is very important that 3/4" crushed stone be used in order to provide proper drainage and prevent build up of hydrostatic pressure, which can lead to wall failure.

Are pavers slippery when wet?

No. Pavers are tested and surpass ADA standards for slip resistance. They also provide excellent skid-resistance under wet or dry conditions. Even sealed pavers are not slippery when sealer is properly applied.

Can I use a sealer on a pool deck?

We do not recommend using a sealer on pool decks unless it is Grace’s Surface Sealer Clear. Other sealers act like a magnifying glass on the surface of the pavers, which raises the temperature to a point that may be uncomfortable to walk on barefoot.

What is the whitish deposit I sometime see on pavers and walls?

This is efflorescence, a natural formation that may appear on any concrete or masonry product. It is actually the residue of soluble salts carried to the surface by moisture - a natural by-product of the chemical reaction between cement and water. Efflorescence does not affect structural integrity and will dissipate over time. It is not indicative of a flawed product. If desired, it can be removed using specialty cleaners. What is the difference between pins, tongue and groove, rear lip, or clips that the various segmental wall systems use? Is one better than the others? There is very little difference between them. They simply serve to connect the units together and create a set-back. A wall develops resistance to soil pressure through the weight of the block, batter of the wall, and friction between the units.

How high can I build a segmental landscape wall?

For most conventional landscape walls, the maximum height is 4' when measured from the top of the footing. With proper engineering and construction, walls well over 20' high can be built!

Is there a way to prevent weeds from growing between the joints of the pavers? Will using a landscape fabric or plastic sheeting help?

Weeds grow from windblown seeds that fall onto pavers and germinate down into the joints. They do not grow up from below, so using a landscape fabric or plastic sheeting is unnecessary. Weeds can be removed by hand, or with a biodegradable herbicide, such as Roundup®. Sealers or sand binders can be useful in helping prevent weed growth and ants.

Can I park cars above my segmental landscape wall?

Yes. Segmental retaining walls are frequently used to provide support to parking areas. However, the wall should be engineered and typically requires the use of geogrid. Vehicles should not be allowed to park within 3' from the back of the wall.

Can segmental walls be used to create raised patio areas?

Yes. Segmental landscape walls are an excellent way to add more outdoor living space. They are used to encase and support the gravel you would add to bring the raised area to the desired height. These wall systems also allow you to easily incorporate stairs or steps into the raised patio.

There is a low spot on my paver driveway. Are the pavers defective?

No. Settlement is often caused by inadequate soil or base compaction, or by poor drainage caused by using the wrong type of gravel. This can be easily repaired by taking up the pavers, correcting the problem and reinstating the pavers.

Is it necessary to start my retaining wall below the frost line?

No. Unlike rigid retaining walls, segmental landscape wall systems are flexible structures and can accommodate slight movement and even settlement without cracking or other types of distress.

What does "interlocking paving" mean?

Interlocking paving is a misleading term. What actually constitutes interlocking is really a dynamic function containing three different components. They are "rotational interlock" (resistance to tipping) "horizontal interlock" (resistance to spreading) "vertical interlock (resistance to sinking)". So, that means for lasting quality you need good containment, good sub base and proper paver thickness. Thicker pavers for driveways thinner pavers for patios.

After you're done paving the work surfaces should I seal it?

Yes, it protects it from leaky cars that might leave oil stains and it stays cleaner for much longer if you seal it right away before it has a chance to get stained. Remember when it's sealed it only takes a hose to clean it off. We use breathable type sealers that protect against just about anything.

Will freezing and thawing damage pavers?

No, damage from ice is virtually non-existent. The joints allow the pavers to move without cracking in freeze and thaw cycles.

What is the difference between "clay pavers & concrete pavers"?

Clay pavers are made with real clay that is mixed, extruded and baked in a kiln at very high temperatures and concrete pavers are made with a special blend of concrete and coloring that is compacted at very high pressures in a special machine.

Which type of paver is better?

There is very little difference between pavers in general. The important difference is the maker of the pavers. Paving materials can vary from one manufacturer to next. The qualities that make a paver perfect are its compressive strength, water absorption rate and abrasion index.