The concept of tightly fitted paving units on a granular base is very old. The first segmental roads were built in 5000 B.C. by the Minoans. With free labor and military dominance, the Romans built the first interstate system over 2000 years ago. Since then almost every culture continues to use segmental pavements.

The Germans developed high efficiency machinery for the production of concrete interlocking pavers in the 1960’s. Production technology quickly spread to England, Europe, Australia, New Zealand, and South Africa in the 1970’s.

Today Germany produces over one billion square feet (100 million square meters). In the mid 1970’s interlocking paver technology hit Canada and quickly spread to the United States. As of 1994, North American sales of interlocking pavers reached 160 million sq. ft. While this represents significant growth over 20 years, it is small in comparison to the other 4 billion sq. ft. sold globally.

Interlocking pavements are flexible pavements. Flexible means that loads are distributed through the base by point-to-point contact and interlock between the aggregate. The base protects the soil subgrade from deforming under loads the base moves slightly when put under heavy load then returns to its original position. This gives them a distinct advantage over rigid forms of pavement such as poured concrete and asphalt, which tend to crack more readily should the base move from loads or natural settlement due to weather. Interlocking pavers are highly resistant to abrasion, freeze - thaw cycles, deicing salts, chemicals and spills of oil and gasoline, which can quite literally melt asphalt. Interlocking concrete pavers are ready for immediate use after installation, there is no need to wait for curing, or dry of the surface and are quickly and easily repaired without any special equipment or materials.

The most important component of any paving project is the area that no one will ever see, this is the subbase. This is the area below the layer of bedding sand that provides the structural support for the paving surface. It has been compared to the chassis of a car or the human skeleton, get the subbase wrong and the whole pavement will soon fall apart. The thickness and necessity of subbase will depend to a great degree on the soil and environmental conditions and surface traffic requirements. This material will vary in thickness from 2" - 6" of 20mm minus gravel, with the thicker base required for driveways or soft soil conditions and the thinner base for walkways and patios. The subbase must also be free draining, as standing water can create a myriad of problems. When compacting the soils and base, it should be done in lifts or layers of no more than 3" at a time. If the lift is too deep the soil or base may never reach full compaction, therefore not fully supporting the layers of paving above. If soil conditions are extremely poor or traffic loads are to be severe, a geotextile fabric may be required to further spread the load over a larger area and reinforce the soils. All grading of the project should be achieved through the subbase layer to attain proper surface drainage. Under no circumstances should the sand layer be used to pickup grade changes.

• The subgrade should be well compacted by a vibratory plate compactor or drum roller.
• The subbase should then be laid in and compacted in 3" lifts.
• The sand layer can now be laid in a consistent layer of 1" well-graded sharp sand, and screeded to form a perfectly flat smooth surface on which to lay the pavers.
• The pavers may now be laid, taking care not to disturb the bedding sand layer. It is best to start your laying of the pavers from a corner of your project, working out on the diagonal. String lines are very helpful at this point to keep your lines of pavers straight.
• When you come to edges where cutting may be required, simply leave gaps and continue laying all of your large areas first, coming back to cut your pavers later.
• After all of the pavers have been laid and cut, an edge restraint must be applied to retain both the pavers and the bedding sand layer.
• Compaction of the pavers into the bedding sand layer comes next. This done with a small plate compactor, compacting the entire area several times in both directions. This will create the lockup of the pavers, binding them together.
• Well-graded fine dried sand is then spread over the surface of the pavers and swept to fill the joints; with one more pass of the compactor your project is complete and ready for use.

Something fairly new to the market are ‘ PAVER LIGHTS’, these can be installed anywhere regular pavers are installed. They are used to guide you through pathways, driveways, and walkways; around pools and patios or anywhere you may require an accent. You can drive directly over them and as they are low voltage, they are perfectly safe even around swimming pools. They can be used in conjunction with other low voltage lights or can run on their own transformer

The edge of segmental paving must be restrained in some manner to hold not only the pavers in position but also the bedding sand layer. There are many ways to edge your pavers: pressure treated wood, reinforced concrete curbs, PVC plastic paver edging or an existing structure. The compacted subbase must extend well past the rear face of these edge restraints to provide proper support.

For years pressure treated wood had been used however it can easily swell up causing splitting and checking. It also can be very hard to support curved areas.

Reinforced concrete curbs can be a great solution, while being a bit expensive and time consuming to put in, they provide superior strength and flexibility while providing a nice accent around the perimeter of the pavers.

PVC paver edging such as ‘Edge Pro’, ‘Pave Edge’, ‘ Diamond Lok’ and ‘Snap Edge’ are specifically designed edge restraints for the interlocking industry. They are low in cost, maintenance free, flexible, and extremely strong and will not crack rot or deteriorate. They are easily installed using 10" galvanized spikes or special galvanized landscape stakes. They are installed below the soil line so are completely hidden upon completion of your project.

There are two main pavingstone manufacturers in British Columbia both Mutual Materials and Abbotsford Concrete provide high quality pavers using a ‘face mix’ process. This consists of a backing mix of larger aggregate combined with a smooth facing mix of very small aggregate, providing a denser colour, superior wear surface and stronger paver than most others in North America. While the surface appears to be painted on it is actually approximately 3/8" thick. Face mix was first used in 1985 during the construction of Expo 86, where over 1,000,000 square feet were installed. Many of these areas remain today around B.C. Place and throughout the Plaza of Nations area. Pavers also provide the checkered Start/Finish line of the Vancouver Indy racetrack.

There are a myriad of shapes, textures and colours available from both suppliers. Only your imagination can limit the possibilities of design when it comes to pavers, circles, fishscale patterns, mosaics, even large scale graphics can be inlaid in your project.

Many people have problems with weed growth. Weeds and grasses rarely grow from under the pavers, but rather weed spores and grass seed can get caught in the crevices between the pavers, germinate and root down the cracks.

Efflorescence is a white salty looking material which sometimes comes to the surface of any coloured concrete surface, while it does not effect the integrity of the paving project it can be rather unsightly.

Coloured concrete pavers look so much nicer when they are wet, it brings out the rich colour you saw in the brochure, colours can mellow in time (that’s a fancy way of saying colours can fade over the years)

The solution to all of these problems can be found in clear acrylic sealers.

The sealer is rolled or sprayed over the pavers, providing a protective coating which will bind the surface sand protecting from weed growth, stop water absorption, preventing efflorescence migration and give a wet look all the time enhancing colour.

If interlocking segmental pavers are properly installed, with the correct subbase, compaction, edging and sealing they can enhance the value of your home or property for decades to come.

Graham Thomas owns Creative Bricks n Blocks Ltd. a landscape supply store in North Vancouver and is a Certified Instructor for the Interlocking Concrete Pavingstone Institute, a international association dedicated to the setting of high standards of paver manufacture and installation.