Step by Step Basics
This is an article that was published in the March 2008 edition of Landscape Construction. It was written by Rocky Womack and includes brick paver repair, details, practices and experiences by The Brick Paver Dr. and other information from David Smith of ICPI.
No matter how well a hardscape project is done, time and environmental conditions will cause that job to deteriorate. The first step in accomplishing hardscape repairs or restorations is to do the work in accordance with the standards of the Interlocking Concrete Pavement Institute (ICPI).
"Sure, it is important that the final repair project is aesthetically pleasing, but you do not want the same problem to reoccur, both for our company name and to provide the customer the most value", says Vince Griffiths, owner of The Brick Paver Dr. () in Detroit, Mich.
He points out that the keys to hardscape longevity are:
Material quality such as aggregates, sand, bricks, etc.
Installation procedure and process, including material depths, grades, compactin density, moisture and treatment of subgrades
Hardscape design - brick configuration and pattern determines and influences overall robustness.
Quality of installation to make sure it is level, bricks are placeed and cut properly, restraints are inplace, compacting is done correctly, joints are in tight, sand is swept away right, etc.
Special features such as geotextile, restraints and adhesive, etc., as necessary
Environmental concerns, such as providing good drainage and dispersing of water; eliminating subsurface conduits, pipes, drain tile, and roots from large trees; and treating for insects, such as ants, etc.
Griffiths says that when hardscapers make repairs, they must first diagnose the problem so they can correct the cause of the hardscape failure, because they don't want the same problem to repeat itself. Second, they must isolate or confine the problem so they can minimize the cost for the customer. Properly repairing the suspect and damaged areas will allow the customer to enjoy their hardscapes for many years to come.
When possible, do the repair the same day during the same visit, because the bedding sand may get wet and make compaction difficult, suggests David Smith, the ICPI mechanical director in Washington, D.C. If rainfall occurs, the existing bedding sand will need to be replaced with fresh bedding sand.
Before making repairs, locate utility lines and determine if the existing paving units can be reinstated. Once the lines are located, the ICPI recommends settings cones, traffic signs or barricades around the area. Next mark the area of pavers to be removed with paint or crayon a few feet wider on each side of the trench opening. Smith says some people don't remove a couple of rows back. When they don't, reinstating becomes difficult and can leave the pavers uneven in height. Smoothing the bedding sand height will also aid in leveling the pavers.
Removing the first paver carefully is crucial. The ICPI advises to scrape the sand from the joints around the paver and pry each side upward with screwdrivers, making sure to begin by prying the short ends first. Once the hardscaper has pried enough of the paver to grasp, he can wiggle it loose and pull upward. He can remove and stack the pavers on a paver cart nearby. If ppavers need to be moved further away, the ICPI recommends placing them on a wooden pallet so they can be moved with a forklift.
In some instances, paver extractors may be necessary if the joint sand has been removed. If vehicles have driven over the area where the damaged pavers are, hardscapers may need to break the pavers in order to remove them. While wearing safety glasses, they can use a small sledgehammer and chisel to accomplish this task.
Hardscapres can reuse the bedding sand. The ICPI advises to stockpile it nearby and see that no foreign material, soil or aggregate base falls into the bedding sand. If the bedding sand becomes contaminated, the ICPI recommends discarding and replacing it with clean sand. The association also recommends leaving an undisturbed area of sand between 6 and 12 inches wide so it can provide a stable support for temporary edge restraints and screeding the bedding sand after the base is reinstated.
When excavating, ICPI suggests keeping the aggregate base material separate from excavated subgrade soil and replacing any soil removed with base material. Using metal or plastic restraints, brace around the pavement opening to keep undisturbed pavers in place. Pin the restraints with metal spikes.
To finish the repair job, compact the soil at the bottom of the trench before placing and compacting the base material, according to ICPI. Place and compact a crushed stone aggregate base in 2 to 4-inch lifts.
When replacing the base material, monitor the density of the compacted soil subgrade and base to prevent rutting and prematues failure. A dynamic cone penetrometer can be used to monitor the density of each lift. If the reading indicates that the soil is too dry, ICPI recommends spraying a small amount of water over each lift prior to compacting.
Replacing the bedding layer may be necessary if it was disturbed. To replace it, remove two additional rows of pavers. Clean the sand off the pavers and set them aside. The ICPI advises leaving 6 to 8 inches of undisturbed bedding sand exposed after removing any pavers, because it will guide the screeding of fresh bedding sand over the compacted and leveled base. Remove any temporary edge restraints and spread the bedding across the base to about two-thirds of its full thickness. Place metal screed pipes on the base and in the bedding sand. This helps to control thickness. Remember that the base will need a slight crown or rise in the center to compensate for minor settling.
The final step is to reinstate the pavers. The ICPI suggests pulling and securing string lines every 6 to 10 feet across the opening along the pavement joints. Follow these string lines so the joints of reinstated pavers will remain aligned. Working from the smaller end of the opening and moving uphill, lay the remaining pavers. Next, place the pavers in their original form and compact them with at least two passes of a plate compactor, overlapping onto the undisturbed pavers, according to ICPI. Spread the joint sand and compact until the joints cannot accept anymore sand and sweep any excess sand.
Sometimes a simple repair won't provide the desired outcome; in those cases a reconstruction may be necessary.
The Brick Paver Dr. photographs the project before the job and after the work is completed. "This serves as a great reinstall reference if the hardscape design is complicated and finally serves as a great reference for customer discussions if there are any disputes on the original job condition", Griffiths says.
Reconstruction starts with removing and thoroughly cleaning all bricks as well as removing all sub materials. Install new materials in accordance with ICPI brick paving standards, Griffiths says, and if necessary, install the bricks using the before photo as a reference. Install them to match their original location or pattern. Next, plate compact the bricks and apply sweeping sand to the joints. Water applied to the polymeric sand will start to harden. After this, apply a sealer.
"A very important step not mentioned as part of the process is to correct what was diagnosed as the cause of the hardscape failure", Griffiths says.
He adds that the repair of retaining walls or raised patios can become involved, because the bricks or blocks are generally fastened with adhesive and can be damaged when being disassembled. In most cases, Griffiths says, "the failures are due to poor base preparation, poor drainage or lack of geotextile material."
Getting to the source
Several Causes of hardscape failures can be solved with a little effort. For instance, when pavers have settled, Griffiths suggests reinstalling them following ICPI standards. If pavers have raised, check the drain tile underneath to see if it's plugged; if condiut or other utility provisions are underneath they will need to be removed; if roots have grown underneath those will have to be removed.
Poor water drainage, such as downspouts or gutters could cause problems with pavers such as angling. Reinstall pavers and apply joint sand and seal them. Provide a maintenance schedule. If a wall or patio has collapsed, install geotextile and provide adequate drainage.
If there is a pest problem, such as ants, treat the area with an insecticide or Borax.
When evaluating a possible repair job, hardscapers can follow some basic steps. Griffiths says they should review the problem and establish who did the work and when, so they can help determine whether a professional completed the job and whether it was a short-term or long-term failure. He says to remove a few bricks and investigate the base material type, depths, presence of moisture and water, presence of undergrouhd objects: insects, conduits, drain pipes, etc.
Next, review the scope of the job to determine the labor and material required for quotation and bid purposes. "This would be based on whether this is a very isolated repair or a major reconstruction project and a possible problem cause that has to be corrected", Griffiths says.
Once the problem is diagnosed, he recommends explaining to the customer what the concern is, what the scope of the project is, whether the hardscape is ICPI certified and the quality of work he offers, as well as his past experience and other credentials.
For more information on hardscape repair, visit the ICPI Web site at www.icpi.org.
The author is a Freelance writer in Danville, Va.
When replacing the base material, monitor te density of the compacted soil subgrade and base to prevent rutting and premature failure. A dynamic cone penetrometer can be used to monitor the density of each lift. If the reading indicates that the soil is too dry, ICPI recommends spraying a small amount of water over each lift prior to compacting.
Replacing the bedding sand layer may be necessary if it was disturbed. To replace it, remove two additional rows of pavers. Clean the sand off the pavers and set them aside. The ICPI advises leaving 6 to 8 inches of undisturbed bedding sand exposed after removing any pavers, because it will guide the screeding of fresh bedding sand over the compacted and leveled base. Remove any temporary edge restraints and spread the bedding sand across the base to about two-thirds of its full thickness. Place metal screed pipes on the base and in the bedding sand. This helps to control thickness. Remember that the base will need a slight crown or rise in the center to compensate for minor settling.
The final step is to reinstate the pavers. The ICPI suggests pulling and securing string line every 6 to 10 feet across the opening along the pavement joints. Follow these string lines so the joints of reinstated pavers will remain aligned. Working from the smaller end of the opening and moving uphill, lay the remaining pavers. Next, place the pavers in their original form and compact them with at least two passes of a plate compactor, overlapping onto the undisturbed pavers, according to ICPI. Spread the joint sand and compact until the joints cannot accept anymroe sand and sweep any excess sand.
As a heavy traffic area, this porch landing has lost its aesthetic appeal with gaps between the bricks.
After properly repairing the steps of this walkway by ICPI standards it will now hold up to foot traffic.
The paving around this deck post needs some reworking.
Porch steps receive a lot of foot traffic and require updates.
The reinstallation around this deck post is a definite improvement.