Arguably this is not a sexy topic, but when considering the type of patio material to choose for your pool, its best to have all the info. To breakdown in depth the differences in pavers, Pool Pros put together this great article. Its a little long but well worth the read. Lets get to it.
Pavers offer a durable and beautiful hardscape solution for many applications (whether they are used for pedestrian or vehicular circulation). In most cases, they come with a larger up-front price tag, but over time pavers will outperform slab concrete. Thus, saving the client money while providing a more visually appealing end product and greater return on investment. This article will define and analyze the components that comprise a conventional paver system. Over the past twenty years, paver technology and best management practices have drastically evolved, benefitting both the consumer and contractor.
PERMEABLE VS NON-PERMEABLE PAVER SYSTEMS
Before we delve into the parts and process of installing pavers, it is important to understand how paver systems are designed to address the issue of stormwater. Water can be a major detriment to the success and longevity of a hardscape system - so control is key. Proper installation techniques will ensure that the flow of stormwater does not lead to system failure.
NON PERMEABLE PAVERS
The two main types of paver systems are "permeable" and "non-permeable." A traditional paver system would be considered non-permeable in that it does not allow for stormwater to infiltrate through the system. Water is instead moved at the surface level of the pavers. This is primarily done through pitch or designed slope throughout the project area. Typically, a patio will be designed to drop about one inch in slope for every ten feet of length. Such a slope is imperceptible when moving through the hardscape but will ensure that there are no areas where water can accumulate (or puddle) on the surface.
PERMEABLE PAVERS
Permeable paving systems are a relatively new innovation. Instead of directing the flow of storwater at the surface level, permeable systems allow water to infiltrate through the joints of the pavers, through the granular base material and into the sub-grade soils. In order to allow the passage of water through, the permeable system has specific design features such as increased joint spacing, high porosity bedding material and "open-graded" gravel base.
COMPONENTS
Let’s now discuss the separate components that comprise a paver system and review the relative functions for each. Below is a list of paver system elements along with a description of their relative purpose along with different material alternatives.
SUB BASE
The first step in almost every hardscape installation is excavation. Excavating the existing soils on site is necessary in order to provide enough space for the base material needed below the pavers. After the excavation is complete, what lies beneath the project site is considered the “sub-base.” Essentially, this term simply refers to the virgin soil that has been exposed after excavation of the area is complete. An important step that is often overlooked is compaction of this sub-base material (before adding any gravel material for the base). There are three soil types including cohesive soils (clay), granular soils (sand) and organic soils (planting) with different rates of compaction for each. Determining what soils you have on site will help guide how much sub-base compaction is necessary. In some cases (such as clay soils with high pliability) a soil amendment like S-type mortar may be needed to help solidify the sub-base material before gravel is added.
GEO TEXTILES
Depending on site soil conditions, a membrane layer might be needed in order to keep the gravel base material separate from the soils beneath. The geotextile category includes both geo fabric and filter fabric. Generally speaking, this material should be used when sub-base soil conditions are especially sandy. Essentially, the engineered fabric will keep gravel from migrating into the sub-base soil layer and help prevent settling of the paver system over time.
GRAVEL BASE
Preparation of the gravel base is undoubtedly one of the most important steps for any hardscape installation. Proper compaction (achieving 95% density of any given medium) will minimize the chance of settling and provide a suitable base for pavers that can withstand the freeze-thaw cycles of colder climates. In many paver system installations, the gravel base is constructed of 3/4" crushed gravel with fines. This is generally referred to as road base, crushed gravel (with fines) or crushed stone #57. The mixture of larger sized chunks of gravel (around 3/4 - 1") with very fine gravel material creates a medium that is easily compactible and ideal for hardscape bases.
In specific cases such as permeable paver systems, a different type of base material is used. This material is called 3/4" clear stone and has been put through a sieve to ensure that it does not include any fine material. Clear stone allows for improved drainage as it provides cavity space between the rocks to allow for the passage of water through the system.
In both cases of crushed stone #57 and 3/4" clear stone, the larger pieces of rock are angular. It is this angular shape that creates "interlock" of the base material. Rounded stone material will not attain this level of cohesion as the particles will push away from one another over time. The two most important factors regarding gravel base construction is selecting the correct type of stone material and proper compaction.
BEDDING LAYER
A bedding layer provides a thin layer of medium for the final setting of the pavers and is usually one inch in depth (or less). Again, the type of material specified here is dependent on the paver system as it relates to permeability. The bedding layer of a traditional, non-permeable system typically employs concrete sand. This material consists of sand with very small angular chips of stone that help improve drainage. For non-permeable systems, concrete sand is the only bedding material approved for interlocking pavers by the ICPI (Interlocking Concrete Paving Institute).
For permeable paver systems, the setting bed is made of a material called "High Performance Bedding." This material is a crushed and washed limestone product that is angular in form and typically about 1/4" in size. It allows for increased permeability and is self compacting.
PAVER
Pavers or paving stones are modular units of concrete, clay or natural stone that interlock to provide a hardscape surface/exterior flooring. Over the past twenty years, there has been an influx of segmental paver dealers that offer a wide range of products to choose from. Pavers come in an assortment of colors, sizes, textures/finishes and thickness.
For an in depth review of different paver styles (including a description of paver features) check out the link to the blog article below... NO LINK
EDGE RESTRAINT
This is one of the final steps of paver installations (before the application of joint fill material). The process is simple but extremely important in the structural integrity of the hardscape installation itself. Without an edge restraint, the pavers will shift and move- creating larger voids between the paving stones. Plastic edge restraint is the most popular choice because it is easy to use, durable and flexible (to meet curves- if the proposed patio is not rectilinear in form). Plastic edge restraint is a heavy duty plastic strip that is secured by 12" spikes (widely available at hardscape dealers and most DIY, big-box hardware stores). Over time the spikes are meant to corrode which helps keep the plastic form in place. Depending on local climate, the plastic restraint may begin to heave and in some cases rise above the profile of the paver surface. However, this is a relatively easy fix to remove the old restraints and set new ones at the edge, if necessary.
Other options include poured in place concrete curbs/bands, edging stones or concrete restraint that is troweled along the edge of the pavers and eventually buried by mulch or dirt. Concrete options may be less expensive in relative material costs, but are also very time consuming with respect to installation. Troweled concrete edge restraint is prone to cracking in colder climates and may lead to failure.
***Note: Don't ever use treated lumber for a paver edge restraint! Any type of wood material (even treated lumber) will deteriorate over time- especially when placed under ground. The moisture content of the ground will eventually lead to rot and without proper restraint, the paver installation will lose its structural integrity.
JOINT STABILIZING MATERIAL
In conventional systems, polymeric paver locking sand is the most commonly used medium for filling the joint space between pavers. Polymeric sand is a mixture of very fine sand with additives such as silica. The sand mixture also includes bonding agents or polymers that activate when water is added. It provides a solid and durable bond that helps lock pavers into place and keep a clean, finished look to the patio (when installed properly). In addition, polymeric sand outperforms traditional sand infill because it is much more resistant to insect infestation and weed growth.
For permeable paver systems, the joint filling material is a crushed, angular chip stone. The relative size of the chip stone is dependent on width of the joint space between pavers but is usually between 1/16" and 3/8." This material allows for maximum infiltration of stormwater by providing pore space between the larger particles. Both polmeric sand and permeable chip fill come in an array of different colors to best match the surface of the specified paver.
POPULAR PAVER MANUFACTURERS & DEALERS
Unilock: https://unilock.com/pavers/
County Materials: https://www.countymaterials.com/en/products/landscaping/pavers
Belgard : https://www.belgard.com/products/pavers/
Techo-Bloc: https://www.techo-bloc.com/shop/pavers
MORAL OF THE STORY
There is more than 1 way to skin a cat but Paver Patio installation has come a looonnnnggg way in the past 15 years. There are still alot of hardscapers stuck in the old ways that have been surpassed by newer best practices that create higher quality longer lasting paver system installations. Be sure to ask about the details of the installation process your hardscaper plans to implement to ensure the longevity of your pool paver system. If its not similar to what is outline above it may be time to continue searching for a qualified hardscaper.
SHAMELESS CALL TO ACTION
Do you need tips or help in creating a tailored landscape plan for your upcoming pool project? Contact Pool Pros today @ 920-771-0107. Our in house Landscape Architect and Pool Project designer are ready and waiting to help you create the Poolscape of your dreams. When Quality Counts, Count on Pool Pros
CONTENT SOURCES
Edge Restraint
Thru-mix pavers vs face-mix pavers:
Geotextile vs. Geogrid: What’s the Difference?
Detail drawings/section diagrams
"Soil Compaction: Methods, Meaning and Effects"
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