Maintenance and repair of interlocking concrete paving systems

by jason_cramp | June 24, 2015 8:30 am

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By Brian Burton

Author’s note: There are profitable long-term opportunities for pool and spa contractors in the maturing markets for interlocking concrete pavers (ICPs). In addition to excellent appearance and durability, ICPs offer a host of attractive landscaping possibilities as a result of the vast range of colours, textures, and shapes available. This article is the second of a two-part series which will provide readers information on appropriate methods to maintain and repair these hardscaping systems.

One of the benefits of interlocking concrete pavers (ICPs) is the relative ease and speed of routine maintenance and minor repairs. For example, in cases where paving units may have settled as a result of rainfall, severe weather, or repeated loads from heavy vehicles, it is a relatively simple procedure to remove the paving unit(s) in order to undertake repairs to the base. After this process is complete, the pavers can be re-installed in their original position.

In addition to their durability, ICPs are also easy to maintain. In fact, when properly installed using the correct materials, they generally require minimal care. However, periodic routine maintenance does help to extend their effective service life and enhance the overall appearance of installations.

Improving one’s general knowledge and specific skills regarding routine maintenance and minor repairs definitely pays off in the long run for pool/landscape contractors. In some cases, this knowledge will help in answering customers’ questions or providing advice on how to look after their hardscaping investment. In other instances, minor repairs may be required under installation warranties. In either event, it represents good customer service and the result is most often a satisfied customer and more repeat business.

According to many marketing experts, it is also an excellent way to increase one’s client base and improve a company’s reputation. This form of customer service is one of the best ways to generate new leads.

Spring has sprung

The arrival of spring and warm weather provides the perfect opportunity to check recent interlocking concrete pavement installations. Indeed, one may want to pay particular attention and deal with chewing gum residuals and oil stains, which both can be easily removed with some of the newer proprietary cleaning products. As a rule, the longer these stains are left in place, the harder they are to remove.

Visual inspection

A visual inspection of paving stone installations is recommended at least once a year to identify any routine maintenance or minor repairs that may be required. Under most conditions, moss and/or lichens will not grow on pavers unless the area is subject to constant moisture and is heavily shaded. If such growth does occur, the area should be scrapped with a putty knife and then scrubbed with soap and a stiff nylon brush. Alternatively, the area can be treated with a weed killer applied in accordance with the manufacturer’s instructions and city bylaws regarding pesticide use.

Removing efflorescence

Efflorescence is the result of a temporary phenomenon which occurs naturally on most products that contain cement. It usually appears in the form of a white deposit on the surface which shows up during the first one or two years. Efflorescence is caused when soluble salts from the cement react with the atmosphere to produce calcium carbonate (CaCO₃). It is important to note it does not affect the structural integrity or durability of paving stones. It will normally disappear in time with exposure to the elements. If required, these deposits can be removed by hosing down the area or using cleaning products which are designed for this purpose.

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High-pressure cleaning

In some cases, periodic pressure cleaning of paving stones may be required at prominent entrance locations. Typically, a high-pressure sprayer with sufficient force to loosen dirt and clean the paving units will work quite well. (Note: When using pressure sprayers, the water should be applied at a 30-degree angle to avoid loss of joint sand.) For smaller areas, adequate cleaning can often be achieved without high-pressure cleaning equipment. For residential patios, walks, or small driveways, cleaners can be applied with brushes to remove dirt. After scrubbing the pavers, the surface should be cleaned and rinsed thoroughly with water.

When cleaning pavers around pools, high-pressure spraying is not normally recommended. To avoid water chemistry issues professional landscapers typically use the water stream from a garden hose, carefully applied at an angle, to avoid water, sand, or debris from entering the pool or other bathing vessel.

Then, pavers are cleaned by hand using a solution of household bleach and water (mixed using a proportion of one part bleach to four parts water), or a mixture of two quarts of white vinegar mixed in 3.78 L (1 gal) of water. Using a reasonably stiff scrub brush, it should be possible to clean two to three pavers at a time until the job is complete. After this is accomplished, rinse the pavers with the garden hose, remembering to propel the stream of water away from the pool or bathing vessel.

Minor repairs for paving stones

The combined effects of frequent freeze-thaw cycles, moisture, and vehicular traffic over time can result in a noticeable settlement of pavers, particularly near curbs, site fixtures, and walls. Settlement can also occur as a result of loss of bedding sand or base materials usually as a result of rainfall and near downspouts where water flows directly onto the pavers during rainstorms. Fortunately, this is not a permanent problem and can be rectified.

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To avoid pool structure problems caused by heavy compaction equipment, a hand tamper or rubber mallet is typically recommended. For new pool and bathing vessel installations many contractors have successfully installed 610 mm² (24 in.²) landscape stones at the perimeter, leaving approximately 51 mm (2 in.) for installation of the required bedding sand. This fine bedding sand can be adequately compacted by hand thus avoiding mechanized compaction.

To repair base materials under the paving units that have shifted (and those in close proximity), the pavers should be removed and set aside to be re-installed later. If the settlement is minor (i.e. fewer than 10 mm [0.4 in.]), additional bedding sand can be added with the pavers placed at a slightly higher elevation than existing units and then compacted so that they are level with surrounding pavement surfaces. If settlement is greater than 10 mm, then the bedding sand should be removed and the depression filled with base material and compacted.

The next step is to replace the bedding sand and pavers as previously described. (When there are many cut pavers to re-install, it is a good idea to number the pavers with chalk prior to removal to allow for proper re-installation.)

When re-installing pavers, the joint between units should be kept tight (2 to 4 mm [0.7 to 0.15 in.). After installing and compacting the pavers, the joints should be filled with sand and the area further compacted.

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Replacing damaged pavers

Although cracked or chipped pavers are rare occurrences, accidental breakage does occasionally occur. One of the benefits of ICPs is the ability to remove individual units and replace them with new ones. (At the completion of the initial project, ideally the contractor should leave extra pavers at the site for this purpose, thereby avoiding any noticeable variation in colour because slight variations can occur from traffic-borne dirt accumulating on surrounding pavers.)

Removal can be accomplished by carefully wedging individual pavers out of position using hand tools such as a metal pry bar or screwdriver, although specials tools are also now available. Removal can be made easier by digging out as much joint sand as possible with a putty knife and/or by shop vacuuming and wetting the joint sand.

The next step is to begin prying on the short end of the paver. It will rise a small distance with each pry. Once high enough, it can be grabbed and pulled free. After the first paver is removed, additional units will easily follow, if required. In some cases, pavers may need to be broken with a cold chisel and maul to enable removal. Protective eyewear should always be worn during this process.

It is all about the sand

The sand which fills the joints between interlocking segmental unit pavers plays an essential role in the long-term performance and appearance of the system. The joint sand and the edge restraints installed around the perimeter of the surface help to create and maintain ‘interlock’ between the neighbouring units. The term interlock describes the transferring of vertical loads (applied to the surface of the pavement), to a horizontal direction exerted on the sides of the pavers. The tightly compacted joint sand (and edge restraints) prevents the individual units from losing interlock and moving in isolation to each other. When joints are tight and the sand in them is secure, the result is an incredibly strong, yet flexible pavement system that can be used in a wide range of applications.

Most pavers are designed with spacer ‘nibs’ that help maintain a uniform 2- to 4-mm (0.7- to 0.15-in.) space between units. This space allows fine sand grains, which are applied after placement of the pavers, to completely fill this space. (During construction, pavers are placed and compacted with a vibrating plate compactor except around pools where a 254-mm² (10-in.²) hand tamper or rubber mallet is used.

After the first compaction, fine, dry sand is swept into the joints. The best sand by far for this application is called mason sand, which is used to make mortar. Limestone screenings should never be used.)

This sand, however, without treatment of one form or another, has a tendency to erode over time as the result of traffic, wind, manual or power sweeping or cleaning, insects (such as ants), and the combined effects of rain, snow, and ice. When the sand is lost from the joint space it is typically replaced by soil or dirt. When this occurs, it creates conditions that will often result in the growth of weeds.

Stabilizing joint sand

Over the past two years, a number of companies have developed products that stabilize and protect ICP pavement systems from sand loss. These products stabilize joint sand and can also accelerate the natural weathering processes. They effectively and permanently bind the sand particles together in a flexible, yet durable state. Joint stabilizers have proven important to the hardscape industry as they prevent weed growth, which has long been a complaint about ICP systems.

In addition to avoiding sand loss from the erosive forces of wind, water, and other elements, which can lead to the settlement of pavers, an additional benefit of the installation of a joint stabilizer is the increased service life and durability it provides to the entire pavement installation. The growth of weeds is the beginning of the deterioration of the entire pavement installation, and once the process has begun it is difficult to control and expensive to repair. It makes much more sense to install a joint stabilizer at the time of installation or after a proper cleaning.

[5]Brian Burton operates a multidisciplinary firm that specializes in website design and development, and technical business writing. The firm also assists companies interested in selling goods and services to governments and institutions. He can be reached via e-mail at burton@award-bid-management.com[6].

Source URL: https://www.poolspamarketing.com/trade/maintenance-and-repair-of-interlocking-concrete-paving-systems/

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