Yesterday I met with Al Martin, a UNILOCK sales representative for North America's largest brick paver manufacturer. We were discussing the challenges that the climate in southeast Michigan presents for interlocking brick pavers and modular retaining walls.
We both agree that our frequent "freeze thaw cycles" , the cycle of the ground freezing and thawing during the winter months, creates a lot of paving damage. It has been no secrete that the roads & highways in the Detroit area exhibit these damages like no other metropolitan area in the country, with Chicago a close second. I would like to comment on the effects of sub grade frost on pavements.
People enjoy the warmer weather here in Michigan during winter month's, but like most good things, there is always a price. When the ground freezes, water or moisture does not trickle down through the water table. Typically, in the Detroit area the average frozen ground depth is 3 feet. This is the reason footings for deck posts or masonry walls must be a minimum of 3.5 feet so the frost does not get below. When the top of this frozen ground starts to "thaw" due to warm weather, it becomes mushy & permeable. The soil below brick pavers, concrete, and asphalt becomes unstable and falters from loads (traffic) and voids in the subsoil. To add more salt (no pun intended) to the wound, it refreezes and traps more moisture between the frozen ground below and the surface. This freeze thaw cycle creates tremendous stress on any pavement by heaving and contracting.
It is not unusual for the Detroit and Chicago areas to experience over 30 freeze thaw cycles during the winter months (Dec thru Mar). This is probably the equivalent of 5 winter frosts versus 1 for a northern city like Minnesota. Many municipalities try to reduce the damaging effects of frost thawing by imposing "Frost Laws". These laws typically reduce the weight allowed by trucks to haul by 50%.
This background leads us to the the conversation I had with Al Martin on brick pavers & retaining walls. It is obvious why UNILOCK locates most of its brick paver manufacturing plants in Chicago, Detroit, Cleveland, New York, Ontario Canada, Toronto, etc.. . These cities fall in what I call the Frost Belt. Interlocking Brick Pavers and Modular Retaining Walls are the most economical and functional pavement for the "frost belt" over time. Repairs of brick pavers is much more economical than repairs of stamped concrete or asphalt. Over 60 years of paving stone experience & feedback has proved this throughout Europe, Australia, and North America.
Many of my clients blame their brick paver repairs on poor installation and this is not always true. Often I do see brick paver patios, sidewalks, and driveways that were poorly designed and installed. The first thing I point out to them is how many times in the last 15 years did the County or State redo that stretch of highway nearby. Usually, it has been redone twice so that is 3 different pavements, sometimes 3ft thick of concrete, that have been totally removed and replaced on average 5-6 years.
Brick pavers and retaining walls that are properly monitored and maintained will out perform any wood deck, stamped concrete or ashalt pavement. Whether you perform brick paver maintenance yourself or use a professional, you can enjoy the financial and aesthic value of paving stones for a lifetime!
Showing posts with label repair of brick pavers. Show all posts
Showing posts with label repair of brick pavers. Show all posts
May 28, 2009
May 16, 2009
The Top Brick Paver Repairs
After 25 years of installing and repairing brick pavers in Ann Arbor, I have come up with a Top List of repairs that I have seen and done. Brick Paver repairs are not uncommon in States with continued frost damage but these particular repairs are the most common.
SOLDIER COURSE SETTLING:
This particular interlocking brick paver repair is the most prevalent. This is the outside brick border that frames most brick paver patios, walkways, or driveways. It most cases, this row of "soldiers" settles or moves more frequently. The main cause is under prepping the base. Alot of installers only install the base to the exact width of the brick paver installation. When this is done, the edge restraint, plastic pvc or cement bead, is not properly installed on the same paver base material, thus this brick paver edge restraint fails and the concrete paver moves with it. It is also very important to cover the outside edge restraint with landscaping, such as, grass, ground cover, or mulch, to protect from long term erosion.
The most evident of this brick paver soldier course settling is the row of brick behind the caps of modular retaining walls and steps. Again, it is the under prepping of base behind these wall blocks. When you build up the base behind these modular blocks, you must compact carefully in 2-3" lifts. The most important step is to fill all voids or gaps with compactible base material, not sand. Over the last 8 years , the use of a geo-textile filter fabric is important to use behind these modular blocks to give added support to the base.
LOOSE PAVERS or WEED GROWTH:
This brick paver repair is the easiest to avoid, but is seldom prevented. The lock up of interlocking brick pavers occurs when the plate compactor goes over the top of the pavers, thus embedding them down in the 1" bedding course (usually a course sand). What occurs at this point is the the bedding course sand "jets up" through the joints from below. This is much like sticking your hand down into sand and the sand comes up between your fingers. The final crucial step is to then sweep an approved joint sand into all joints of your brick paver walkway, patio, or driveway, run the brick paver compactor over the entire brick installation again to jiggle down any loose sand, and then finish off with a final sweep. The joint sand keeps the pavers from moving laterally and keeps them from coming loose. Keeping the joint sand filled in the brick paver joints also helps prevent dirt or weed seeds embedding into the joints.
I will go back to brick paver installations that where installed 5 years prior, and no joint sand will be in the joints. I can stick my finger in most joints and feel the bottom of the paver. When joints are not filled, the pavers can move laterally and come loose. The most damaging effect is that water will easily come of the paver surface, tunnel down through the joints unabated, and slowly erode the the base material below.
Just 15-20 minutes of your time and $10-15 worth of joint sand each Spring to sweep your paver patio will help you avoid 100's of dollars of brick paver repairs and frustrations of a unsightly patio.
Brick Paver Dips or Waves:
This repair is usually immediately evident if a poor paver installation is performed. Keep in mind that any & all repairs are NOT the result of poor installation. The whole premise of interlocking brick pavers is to withstand the effects of winter frost or ground settling, at a minimal cost of resetting or repair. The biggest cost savings is the ability of the paver repairs service to reuse the same products, thus reducing material costs.
A poor brick paver installation can begin with a poor base preparation. Often installers cut cost & time by not excavating deep enough to install a proper base depth. A basic base material depth for patios & walkways is 4-6" and driveways 10-12". Actual base material depths vary due to weight requirements and soil conditions to name a couple. If the base material depth is compromised, your brick paver patio may not drain properly and therefore have added stress during frost periods. It is also very, very, important to compact the subsoil (dirt) prior to installing the base material on top.
Another common mistake by brick paver installers is not compacting the base in "lifts". This means they should not dump more that 3-4" thick of base material at any given time with out spreading evenly and compacting. The common brick paver compactor can not properly compact more than 4" lifts at a time. I see many contractors filling raised brick paver patios or driveways with base material over 8" high, then raking and compacting the top only! This will have an extreme effect on the performance of the brick pavers!
Another faux pas of installing paver base is not spreading and compacting in level lifts. Some paving contractors rake out, compact, and then install bedding course over a "wavy" base installation. Keep in mind that the bedding course can not make up for the uneveness of the base material in terms of long term paver performance. What you observe with base material installation will mirror the brick pavers in the future!
This is just some of the top brick paver repairs that I have seen & performed over the many years that the brick paver industry has experienced here in North America. In the fuure, I will continue my list and requirements.
SOLDIER COURSE SETTLING:
This particular interlocking brick paver repair is the most prevalent. This is the outside brick border that frames most brick paver patios, walkways, or driveways. It most cases, this row of "soldiers" settles or moves more frequently. The main cause is under prepping the base. Alot of installers only install the base to the exact width of the brick paver installation. When this is done, the edge restraint, plastic pvc or cement bead, is not properly installed on the same paver base material, thus this brick paver edge restraint fails and the concrete paver moves with it. It is also very important to cover the outside edge restraint with landscaping, such as, grass, ground cover, or mulch, to protect from long term erosion.
The most evident of this brick paver soldier course settling is the row of brick behind the caps of modular retaining walls and steps. Again, it is the under prepping of base behind these wall blocks. When you build up the base behind these modular blocks, you must compact carefully in 2-3" lifts. The most important step is to fill all voids or gaps with compactible base material, not sand. Over the last 8 years , the use of a geo-textile filter fabric is important to use behind these modular blocks to give added support to the base.
LOOSE PAVERS or WEED GROWTH:
This brick paver repair is the easiest to avoid, but is seldom prevented. The lock up of interlocking brick pavers occurs when the plate compactor goes over the top of the pavers, thus embedding them down in the 1" bedding course (usually a course sand). What occurs at this point is the the bedding course sand "jets up" through the joints from below. This is much like sticking your hand down into sand and the sand comes up between your fingers. The final crucial step is to then sweep an approved joint sand into all joints of your brick paver walkway, patio, or driveway, run the brick paver compactor over the entire brick installation again to jiggle down any loose sand, and then finish off with a final sweep. The joint sand keeps the pavers from moving laterally and keeps them from coming loose. Keeping the joint sand filled in the brick paver joints also helps prevent dirt or weed seeds embedding into the joints.
I will go back to brick paver installations that where installed 5 years prior, and no joint sand will be in the joints. I can stick my finger in most joints and feel the bottom of the paver. When joints are not filled, the pavers can move laterally and come loose. The most damaging effect is that water will easily come of the paver surface, tunnel down through the joints unabated, and slowly erode the the base material below.
Just 15-20 minutes of your time and $10-15 worth of joint sand each Spring to sweep your paver patio will help you avoid 100's of dollars of brick paver repairs and frustrations of a unsightly patio.
Brick Paver Dips or Waves:
This repair is usually immediately evident if a poor paver installation is performed. Keep in mind that any & all repairs are NOT the result of poor installation. The whole premise of interlocking brick pavers is to withstand the effects of winter frost or ground settling, at a minimal cost of resetting or repair. The biggest cost savings is the ability of the paver repairs service to reuse the same products, thus reducing material costs.
A poor brick paver installation can begin with a poor base preparation. Often installers cut cost & time by not excavating deep enough to install a proper base depth. A basic base material depth for patios & walkways is 4-6" and driveways 10-12". Actual base material depths vary due to weight requirements and soil conditions to name a couple. If the base material depth is compromised, your brick paver patio may not drain properly and therefore have added stress during frost periods. It is also very, very, important to compact the subsoil (dirt) prior to installing the base material on top.
Another common mistake by brick paver installers is not compacting the base in "lifts". This means they should not dump more that 3-4" thick of base material at any given time with out spreading evenly and compacting. The common brick paver compactor can not properly compact more than 4" lifts at a time. I see many contractors filling raised brick paver patios or driveways with base material over 8" high, then raking and compacting the top only! This will have an extreme effect on the performance of the brick pavers!
Another faux pas of installing paver base is not spreading and compacting in level lifts. Some paving contractors rake out, compact, and then install bedding course over a "wavy" base installation. Keep in mind that the bedding course can not make up for the uneveness of the base material in terms of long term paver performance. What you observe with base material installation will mirror the brick pavers in the future!
This is just some of the top brick paver repairs that I have seen & performed over the many years that the brick paver industry has experienced here in North America. In the fuure, I will continue my list and requirements.
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