Landscaping & Design Ideas

Living in the Greater Cleveland Ohio area, we are subjected to some pretty severe winter months.  In fact, Forbes Magazine just ranked Cleveland as America’s worst winter city!  While that may be debatable, winters in Cleveland do take their toll, on both our state of mind and our homes & landscaping.

Our company meets with many people who ask us if we do both pavers & stamped concrete.  Or we often hear that the person will probably decide on stamped concrete because they think it will be cheaper.  While the initial installation cost of stamped concrete is often cheaper than pavers, there are some long-term drawbacks to saving a few dollars up front.

This brings us back to the climate here in Northeast Ohio.  The winter freeze-thaw cycles wreak havoc on our roads, both concrete and asphalt, our homes exterior as well as our sidewalks and driveways.  Anyone who drives around Cleveland and its suburbs in spring knows this well.  We cringe every time we hit a large pothole.

The same freeze-thaw cycles that destroy our streets annually are working against our driveways,  sidewalks, and patios at home.  Whether they be asphalt, concrete, stamped concrete, or pavers, our pavements are subjected to these forces throughout the winter.

With concrete or stamped concrete, flaking will occur.  The subgrade may settle, resulting in cracks in the concrete.  And de-icing salts will speed up the deterioration process.  With stamped concrete, the colors will begin to fade and lose their luster after only a few short years.  The only viable option at that point is to wait until it is in such disrepair that it needs to be replaced.  In the mean time, you are left dealing with an eyesore. There is no option to repair.

This is one of the distinct advantages of pavers, and one reason the long term value of pavers far outweighs any initial price difference.  When those same forces work against your paver surface, three types of interlock are at work to keep them in place.  Vertical, horizontal, and rotational interlock insure that the pavers are locked into place.  The inherent joint lines in pavers contribute to the pavement’s strength.

This is not to say that Cleveland winters will not eventually take their toll on a paver surface.  But the good new is that the paver itself will not be damaged.  This allows for repairs to the base by simply lifting out the pavers in the problem area, correcting the base, and laying the pavers back into the pattern.  Sometimes the problem occurs with the edge restraints lifting or cracking, which is also a relatively quick and inexpensive fix.

One great example as to the durability and longevity of pavers comes from Holland.  Living on land that was once ocean that is now protected by dikes, the ground settles 6″-12″ every five to ten years.  The settling is caused by the removal of water in the soil that slowly seeps in from the sea.  The pavers are removed and set aside, while the base is brought back up to grade.  The pavers are then put back in place.  The need for this type of paving system has led to a 1,000 year tradition of using pavers.

On the contrary, we would be lucky if a street or driveway in the Cleveland area lasted just 20 years!  But the beauty of a paver system is that it is repairable, rather than needing replaced.  Keep this in mind when trying to decide between concrete or pavers.

When constructing an interlocking concrete pavement, there are some general minimum guidelines that apply to most areas in the U.S.  These guidelines are geared towards regions with freeze-thaw cycles.  In non freeze-thaw regions with sandy, well drained soils, there may be no base requirements for residential and pedestrian paver surfaces.

The thickness of the base is determined by traffic loads, soil strength, subgrade soil drainage and moisture, and climate.  Local standards for base thickness of asphalt pavements can be applied to surfaces constructed with concrete pavers.

In the Cleveland area, the following minimum thickness should be used:

• Sidewalks, patios, and walkways- 4″
• Residential driveways- 10-12″
• Parking lots and residential streets-10-12″ often more

As you can see, different types of applications have different base requirements.  These are generally the minimums for paver projects in our regions, but they can vary due to soil conditions.  It is important for you or your paver installer to know the base requirements for your project.  This will ensure that the job is installed properly and will last for years to come.

Also remember that base depth does not mean excavation depth.  If your patio or walkway requires a four inch compacted base, you will still need to factor in your finished height, and allow space for both your bedding sand and the thickness of the paver.

For example, if your finished height will be even with the existing grade, and you plan to use a paver that is 2 3/8 inches thick, you will be required to excavate approximately seven inches.  If you plan to use a thicker paver, make sure you allow for the additional thickness when you excavate.  Cutting corners in any phase of a paver project will result in the shortened longevity and usefulness of the paved surface.  By spending the time and energy to achieve proper base thickness, you are providing your paver patio or walkway with a key component of its integrity for the life of the pavement.

Interlocking pavements are considered flexible pavements.  Loads are distributed through the base by surface contact and interlocking through the various materials, including the paver, jointing sand, bedding sand and base.  The base, which is a crushed limestone or recycled concrete, protects the subgrade from deforming under loads.  When a load reaches the soil layer,  it is distributed across a wide area so that the soil does not deform or rut.  Knowing what kind of loads will be used ensures that the proper amount of base material is installed at the time of installation.  Whether it be pedestrian traffic on a backyard patio, or the weight of heavy machinery at a shipping dock, the right base depth ensures that the pavers distribute the load properly to the subgrade below.

Interlocking pavers spread loads across the base, and can move with minor movements in the base without cracking.  This gives pavers an advantage over asphalt or concrete, which can crack if the base moves, or crack from expansion during freeze thaw cycles.  Another advantage of concrete pavers is their strength.  Poured concrete is rated at about 3,000 psi, whereas concrete pavers carry a rating of at least 7,000 psi.  If it does not carry a rating of at least 7,000 psi, it is not technically considered a paver.  More reputable manufacturers, such as Techo-Bloc, Unilock, and Belgard, having ratings of over 10,000 psi.  They also carry a full lifetime warranty that covers the structural integrity of the paver.

Concrete pavers are more durable than asphalt, offering higher resistance to abrasion, freeze thaw cycles, de-icing salts, concentrated loads, and stains.

Poured concrete is considered a rigid pavement that works on the principle of the layer of concrete protecting the soil subgrade.  Loads are spread by the concrete and bridge soft spots in the soil.  Poured concrete is durable, but requires time to cure, whereas pavers are ready for use immediately upon installation.  Poured concrete cracks and deteriorates due to shrinkage, loads,  and weather.  In contrast, the joints in an interlocking pavement contribute to it’s strength.

People often wonder what keeps the pavers from moving after they have been laid. There are 3 types of interlock that keep them in place.

Vertical Interlock is achieved by the shear transfer of loads to surrounding pavers through the sand in the joints.

Rotational Interlock is maintained by the pavers being of sufficient thickness, placed closely together, and restrained by a curb or edge restraint from lateral forces.

Horizontal Interlock is achieved through the use of laying patterns that disperse forces.  Certain shapes have been shown to contribute to horizontal interlock, offering additional resistance to lateral forces.  Stable edge restraints also maintain horizontal interlock, keeping the pavers tight at the edges of the pavement.

If not properly installed, all of these aspects can fail over time.  The result would be heaving, settling, rotating, or separation around the perimeter.  A properly installed paver project would require minimal attention over the lifetime of the pavement.

When trying to find the right contractor for your paver job, there are some important questions you should ask. The answers can reflect differences in job price and job quality amongst different contractors competing for the same job. By looking for the best price in town, consumers may be sacrificing quality, safety, and in some cases liability.

In order to ensure a quality installation, the following questions should be asked:

• How long have they been installing pavers?
• Have they been trained by a manufacturer or by the ICPI?  Do they have a written certificate of completion?
• What percentage of their total business consists of installing pavers?
• Will they provide you with three references?
• Can you contact their references and inspect their jobs?
• Do they have a portfolio of photos to qualify themselves?
• Do they currently have a liability insurance certificate?  While on your property, they should be insured for any damage and injuries that may occur.
• Can the contractor provide proof of Worker Compensation insurance?
• Do they install the job per ICPI specifications?
• Do they guarantee their work for at least one year?  Will they return for an inspection before the guarantee expires?

These questions, along with any job specific questions, will ensure you are selecting a competent contractor for you paver project.

On this web site, in the Paver Services section, we make mention of being ICPI Certified.  That may sound good, but what exactly does it mean?

ICPI, or Interlocking Concrete Pavement Institute, teaches the ICPI Concrete Paver Installer Certification Course.  This course communicates high standards to contractors who build concrete patios, driveways, plazas, parking lots, and streets.

What do certified installers learn at the program?

• Material and labor estimating
• Sound business practices
• Job layout
• Use of labor saving specialty tools
• Soil classification and compaction
• Base material selection and compaction
• Bedding and joint sand selection and installation
• Edge restraints
• Paver selection and installation
• Basic contract law

Considering that these are factors in all paving jobs, you should insist that your hardscape contractor is ICPI certified.  The industry is also pushing for municipalities to require certification for all paver contractors performing work in their cities.  All too often, paving jobs are undertaken by companies that lack the experience and knowledge to successfully complete a job, leaving customers dissatisfied, and giving our industry a bad reputation.

So, why choose an ICPI Certified Installer?

Knowledge:

ICPI certified installers are industry professionals.  They recognize industry standards on constructing interlocking concrete pavements.

Assurance:

You can be sure that a company with a certified installer on staff is dedicated to quality installation standards and on-going education.

Investing Wisely:

You’re investing in a low-maintenance, long-lasting pavement.  Certified installers can help get the job done right the first time and on time.