By Jonathan Hendy and Pete Baloglou of Techo-Bloc
|Techo-Bloc’s Mista pavers can be used for pedestrian
or light vehicular traffic , residential driveways , patios ,
and swimming pool decks.
With the imminent trouble of urban flooding on the rise, permeable pavement (PP) is quickly gaining notoriety as a sleek and ethical solution. Unfortunately, with any great advancement comes cynicism. It’s like JKF said: “Change is the law of life. And those who look only to the past or present are certain to miss the future.” So, let’s challenge the myths of PP. Below we clarify some of the annual, bi-annual, quarterly, and monthly maintenance misinformation surrounding these pavers:
1) My ten-ton static roller will solve all my compaction problems.
Really? Will it really? Will it work with the American Society for Testing and Materials (ASTM) two-inch #8 bedding layer? What about the ASTM four-inch base #57 stone layer? Guess we’re just going to ignore the ASTM #2 and #3’s sub-base stone? Oh, and, what’s the respective lift height and level of moisture for this particular PP installation? More questions are generated than answered by statements like that above. So, lets break it down: If compaction is the process by which the bulk density of an aggregate of matter increases by mechanically driving out air, then to properly increase the density of an aggregate it only makes sense that you absolutely have to know what you’re compacting. If not, you’ll have no idea what the product’s moisture percentage is, what its maximum density is (in other words, when to stop), and the fundamental equipment needed to ensure that nothing goes wrong.
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If you’ve successfully convinced yourself that the consolidation of aggregate layers is your Hail Mary, don’t forget that doing so simply means that your equipment is pushing the stone into the sub-grade or surrounding excavated side soils; that’s displacement, not compaction.
2) In certain climates, traffic loads, and soil conditions a contractor can skip the sub-base in order to save the consumer some money.
No. The explanation to why this statement is so wrong lies in geotextiles and geo-grids, which are both important components of proper structural and hydrologic decisions. For one, geo-synthetic products can add major value and efficiency to PP applications. They can be used to segregate and further the performance in four different scenarios
1. Between the sub-grade soil and sub-base (or base)
2. Between the sub-base and base
3. Between the base and bedding
4. In some designs, intermittently in lifts of the sub-base or base.
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Geo-synthetic products add integrity and are a little investment compared to alternative initial and lifecycle costs. They also aid in filtration of petroleum from stormwater via microbial generation; prevent downward migration of aggregate into preceding layers under the kinetic energy of traffic and; special bonus, are easy to install.
3) Analyzing the renovation site is a long and grueling process.
The site analysis process is nothing to dread. I call this one Pete’s PP Precedents:
1. Start with a common percolation test of on-site soils. It can cost you as little as $100 and is crucial for any PP installation.
2. Make sure you get a soil analysis done for sieve size, bearing ability, and classification. It should set you back a few hundred dollars if done by a geotechnical firm or university annex.
3. Consult the PP and spec guide sections on your manufacturer’s website. Be sure to look out for recommendations on wearing course and cross section of installation options.
4. Step 4 is situational. In critical applications with adjacent subterranean drainage structures, bio-swales, vegetated filter strips, rain-harvesting components, etc., consult an engineer armed with permeable design software.
5. In residential, light commercial, and municipal applications, work with your town officials and product producers to design a PP that pleases the property owner, but that also solidifies your company’s commitment to sustainability.
6. You’re done in my book; take the jump and hit the ground running.
You can hear the echo of the craftsman’s tools in the honest lines and rugged texture of the Blu Collection.
4) Annual, bi-annual, quarterly, and monthly maintenance will be needed after installing PP.
It’s a myth! It’s a myth! It’s a myth! I promise, I’m not the boy who cried wolf. Here are a few things that may affect the level of maintenance:
1. Environment (like shredding trees)
2. Wind and snow (piled) born debris
3. Pedestrian and vehicular pollutants
4. Quality of Erosion and Sediment (E&S) measures
5. Joint width and jointing material
So how often will maintenance really be required? Depending on your total site’s rate of infiltration, maintenance may either never be needed or at incredibly infrequent intervals nearing the 10+ year mark. Still worried about weeds, ants, etc.? Don’t worry, jointing aggregate on the surface is an exaggerated issue and only a concern in rapid water flow situations like flooding or power washing pavement. Weeds, ants and so forth are prevalent in any outdoor pavement, but are, thankfully, easily addressed with common household and gardening remedies.
Techo-Bloc’s Mista Collection
5) Manufacturers of PP systems should not always test their products for Americans with Disabilities Act (ADA) compliance.
Manufacturers of PP systems such as Techo-Bloc, test their products for ADA compliance every single time. Whether or not the ADA is applicable, testing to a standard has everyday residential relevance (i.e., children, elderly, steep slopes, etc.). The act requires that the pavement be firm, stable, and skid resistant. But, wait, what exactly does that mean?
|Techo-Bloc’s Mista Collection|
1. ‘Firm’ applies to the rigid units in PP. Block units must pass stringent tests in order to be durable to everyday wear and tear.
2. ‘Stability’ is subject to the pavement cross-section and design. If the aggregate layers, geo-synthetics, pre-cast curb edging (etc.) are installed correctly, then pavement will be stable under foot, tired and static or dead loads.
3. ‘Skid Resistance’ has to do with the Brungraber Mark 2 test, which uses a pendulum and simulated human skin to determine if a product is safe to walk on with a shoed foot, wheel chair, etc., in even the worst case scenario.
Moral of the story? Comply with ADA standards and give your lawyers a break.
6) Permeable Pavements can only be set in certain patterns for interlock.
Myth #6 is at the core of a very heated debate. Essentially, the word “interlocking,” as it pertains to permeable pavement, is referred to in many different ways. Some manufacturers have chosen to call it SPP (Segmental Permeable Pavements), while the Interlocking Concrete Pavement Institute refers to it as PCIP (Permeable Interlocking Concrete Pavement). At the base of it all, “interlocking” as it pertains to permeable pavement is defined as vertical (jointing sand), horizontal (pattern), and rotational (thickness) unit paving systems. As such, the generally accepted rule, in the industry, is that patterns with the least aligning joints have the most strength and interlock stability.
Rotondo pavers are ideal for developing focal points in tranquil sitting areas like patios or poolsides.
However, Techo-Bloc proved this concept wrong first in its Chambly, QC (300,000 sq. ft.) stocking yard and then at the Lamtec commercial site (80,000 sq. ft.) in PA. Both instillations utilized Techo-Bloc’s Inflo permeable pavement, which was mechanically set using the TB100si proprietary-vacuum-laying-device. The aforementioned properties constantly undergo heavy, industrial traffic moving in many different directions. And yet, the PP running bone pattern that was installed was done so at no cost to load traffic quality. Both have been performing beyond expectation for five years now and have not exhibited any “creep” horizontal movement. Now that’s pushing the boundaries!
If by airing these myths a debate has begun, mission accomplished! “Let’s not play the game, let’s change it.” (Margaret Heffernan) At Techo-Bloc, we don’t believe in following, we believe in redefining. Let’s get the conversation started; what do you think?
Jonathan Hendy is a copywriter and social media coordinator for all things Techo-Bloc. “Paver” Pete Baloglou is director of education at Techo-Bloc. He has been at the forefront of the landscaping industry for 30 years.
Rich texture give San Marino pavers from Techo-Bloc their old-world character and timeless appeal. Two available widths can be combined for a natural, random pattern.