What are my options and how are they built ?
A paver patio can aesthetically transform any yard to the perfect little oasis to relax and entertain other than adding substantial value to your home. Their durability can stand the test of time if built correctly, so before you hire a contractor you should have a basic understanding of how they are constructed. This blog was written to provide a little insight as to what to look for before you get started.
Firstly planning and layout.
You’ll want to determine how big of an area to hardscape will be in proportion with green space on your property. Also keeping in mind the corresponding cost, bigger you go bigger that cheque will be to write. Another important thing to consider is that, you have to pay attention to the lay of the land as water will need drain away from the house.
Secondly we need think about excavation.
Can heavy machinery able to get access to the area? If not, then expect a heavy labour cost to dig it out by hand.Additionally take caution of underground gas lines.
How deep do we need to dig? Factors to take into consideration will include your property soil type, clay subsoil / sandy subsoil. Another factor will be what is the intended use of the space? For vehicular Or pedestrian traffic?DON’T FORGET WHAT SYSTEM TYPE WILL WE USE? PERMEABLE OR SEMI PERMEABLE OR CONCRETE SLAB ON GRADE MORTAR APPLICATION?
Depending on what the hardscape is intended for, it can varry but typically you can expect anywhere from 10”- 24”
VISUALLY THEY ALL LOOK THE SAME ABOVE, BUT ARE THEY ? ITS UNDERNEATH THE PAVER WITH THE STRUCTURE AND DRAINAGE THAT MAKE ALL THE DIFFERENCE.
So what’s the difference ?
This being a traditional semi permeable system type which is designed to be slopped @ 1:48 inch ratio. Which means for every 48” out you need slope decline 1”. Looking closely, the pavers are layed tightly together typically @ 1/8” so minimal water will penetrate through, penetrated water will seep through bedding sand and exit out slopped direction of compacted granular base.
The underlayment consist of 1” bedding material (concrete sand or HPB).
Base material being gravel (3/4 crusher Run) compacted in 4” intervals to a Compaction rate of 12,400 – 56 000 ft Lbs/ft3, using the appropriate Compaction equipment and moisture. Patios and walkways is recommended @ 8” and driveways @14” additionally if Sub-grade is clay like you will want to Add an additional 4” of material and
Compaction rate of 12,400 – 56 000 ft lbs/ft3, using the appropriate compaction equipment and moisture. Patios and walkways is recommended @ 8” and driveways @14” additionally if sub-grade is clay like you will want to add an additional 4” of material and pack the sub-grade well with a layer of clear stone.
Filter cloth installed creating a barrier between the sub-grade and compacted base to avoid contamination over time.
This is a permeable system type which is designed to naturally drain water in a capillary effect back into the sub-grade. Additionally the pavers are laid with a wider spacing @ 1/4” – 1/2” to invite water to penetrate through additionally material within paver joints must be with no exception small stone chip @ 1/16” – 3/8”.
This penetrated water will then seep through bedding course and continue through base course & sub-base course extracting out through fabric cloth back into sub-grade as mother nature intended. Recommended patio and walkways @ 8” and driveways @ 14” sub-base. It is still recommended to slope the structure @ 0.5% decline away from home. Aggregate coursings of sub-base and base course will be compacted in 4” intervals to desired cohesion.
In the instance of clay like sub-grade or any instances where there are reasons of high water volume penetrating the surface there should be an additional layer of sub-base material and interdiction of a weeping tile slopped directed out to sunlight or with a popup if necessary.
Paving slabs on motor setting bed
This is a mortar set system which is most durable & permanent of the three options in structure. It is designed to slope water directly off surface area @ 1:48 ratio meaning for every 4’ out a decline of 1”. Joint spacing of the pavers can be determined to aesthetic preferences with jointing material mixed to a concentrative blend of durability in regards to bonding and strength. Such quality can only be achieved with good materials and should only be installed by a qualified mason. Control joints need to be considered and determined where to place within the design of paver layout abutting concrete pad and must not exceed 16’ in any direction.
The underlayment consists of 3/8” – 3/4” cement bedding, adhered directly against a solid 4” reinforced steel concrete pad providing ultimate durability. Additionally with 4” – 8” layer of compacted clear 3/4 stone in 4” intervals to avoid water settlement under concrete.
Advantages of mortar set pavers
- Low maintenance
- Easy cleaning no joint material washout
- Resistant to point loads
- Resistant to fatigue of traffic patterns
- Resistant to edge blowout
- No chance of vegetation growth
- No insect nesting
Thirdly on the list edge restraints,
Now that we have decided on a hardscaping system that works best, we need to think about the edges surrounding making sure they are built both for aesthetics and strength. As for both permeable dry lay applications, strength will be the main issue in preventing concaving edges.
For wet lay paver application, there are no edge restraint requirement other then for aesthetics.
Finally, deciding on a paver.
Pay close attention to the sides of the pavers, permeable pavers will have larger spacers built onto the sides so that they can be installed effortlessly maintaining proper spacing. Hence they would not be compatible in a semi permeable system.
Additionally its recommended to use manufactured products that are equal in height in a dry lay application, so in it’s final install stage each unit will be compacted equally into the bedding material.
Some may not be Compatible with every layout Design best to consult your Contractor first.
Another thing to pay close attention to is load restrictions. Recommended minimum light pedestrian traffic 11/2” thick and heavy pedestrian and light vehicular traffic 2 1/4 thick and heavy vehicular traffic 2 5/8 thick.
If you have your eye set on a natural stone paver, your best choice is a mortar bed setting, as they are not uniformed in height and packing them in dry bedding material is not practical. Also, they are typically thinner between 1” – 1 3/4” thick making them not durable for heavy pedestrian traffic, unless set into a solid mortar bed they become a solid structure and are acceptable to heavy loads.
DANIEL R. GOLDSMITH
YORK MASONRY GTA.