Ottawa Interlock

An Ottawa Interlock Company with Quality Results!

As an Ottawa interlock company we offer a long lasting product through quality workmanship and materials.  We follow the installation recommendations set by the International Concrete Paving Institute which has specific industry standards for interlock installations.  A properly installed interlock patio should not shift or distort for many years to come.  In Ottawa, interlock is a key element to a backyard that creates it’s own natural feel, the type and color of the stone you choose will make a dramatic effect to your home whether it be a patio, walkway or driveway.

The interlock patio accents this backyard in Ottawa

Interlock patio with a flagstone walkway


Flagstone although not quite the same as interlock adds a natural aura to a backyard.  Flagstone is usually installed in the same manner as interlock but the joints can be filled with media other than polymeric sand, in this case the customer decided to use grass to add some green space.  With rock & stone quarries quite plentyful in Ottawa, supply is definitely not a problem

The small interlock patio in the photo has just enough space for a table and chairs in this small downtown Ottawa backyard.  The combination of elements in this backyard creates a warm atmosphere to help relax the busy city of Ottawa lives.

This project had quite a few elements: retaining wall, cedar fence, cedar shed, interlock, flagstone, sod, flower beds and a cedar deck.  A true landscaping backyard makeover.


When designing an Ottawa interlock project we take numerous factors to determine the best design most importantly being functionality and customer preferences.  When designing we use that latest in 3D CAD design software to give you a real view of what the finished product will look like including your furniture and accessories.  We do offer just a landscape design package if you would like to establish a plan before going through the process of hiring a contractor to do the work, for more info see our Ottawa Landscape Design page. We will also work with any plans which you have provided for your interlock project as well.

We also build raised patios in Ottawa.  While traditionally we would use a retaining wall system to raise an interlock patio, we have another solution which is a steel deck structure with stone paver finish…’s called paver deck.  With this system any elevation is achieved even a 2nd storey patio.  The structure has a 30 manufacturers structural warranty and is featured on Mike Holmes Make It Right television series.



While the process described may vary depending on the project, the installation principles for interlock remain consistent. All our methods are tried, tested and true using the latest installation procedures from the industry, manufacturers and regional requirements.


It’s very important to have a solid plan in place to ensure that your project is executed in an efficient manner as well as it’s best to know what the finished product will look like.  This is why a 3D rendering is really important.  In some cases where it’s a simple design like a standard patio a 3D design may not be required but is still an option.  An interlock project can be quite expensive so it would be best if it were want you wanted the first time rather than not be happy with the project or spend extra money to modify it.


Ottawa interlock design layout before excavation

A simple layout allowed the customer to make adjustments to their new backyard

It’s very important to do a visual interlock layout of the project on site before any work begins.  While putting the design in perspective we’ll be able to confirm the measurements in the design and make sure that everything will be in proportion.

A visual layout is done in a number of ways.  Marking the location of the work area by making visual lines with pins & lines, we also like to establish a finish grade at this point to verify excavation depths as well as if steps or walls will be required.



An Ottawa interlock excavation is very important.  A proper excavation depth will be a major determining factor in the future movement of the stone to be installed.  While things like traffic area and sub-grade soil conditions play a part in deciding the excavation dept as a general rule there should be 10″ of base established for a patio and 16″ for a residential driveway.  It is also recommended that the excavation be 6″ larger than the excavation area to allow for over base.


Ottawa interlock excavation for a retaining wall

A mini-excavator makes for precise work next to this garage

The equipment we use for excavation will vary depending on the project.  If it is a small project less than 100 square feet we may decide to to this by hand and wheel barrel.  For larger projects we may use a skid steer and a mini-excavator to move the job along a little faster.  When using equipment we do recommend the use of landscape mats to protect the road traveled, this will reduce the cost of having to replace the surface traveled over.

A mini excavator allow for a precise excavation when next to structures such as decks for fences.  Our mini excavator is quite narrow which will allow us to fit into just about any backyard.

A skid steer is used to transport material faster and with less labour than a wheel barrel, which this is more efficient the equipment is larger and can create damage to sod if the proper steps are not taken to project it.



Sub-Grade Preparation for Interlock

The sub-grade is to be compacted before any base work is to be completed. Additional steps may also have to be taken (especially for an Ottawa interlock job as the soil type is mostly clay) depending the the type of soil contained in the sub-grade before any work is started. If the soil type is clay it will not compact properly and will need to be stabilized, if this step is not taken the interlock base will never be stable and will have a spongy feel and the end result would be most definitely be movement in the future.

Interlock Base Installation

Ottawa interlock patio in the west end of Ottawa

Preparing the base for this front west end Ottawa interlock Patio

After the excavation and sub grade preparation is complete we can begin to install the base.  The first step in this process is to install geotextile cloth, this will prevent the base from migrating into the finer particles of the sub grade.  Once the geo cloth is installed we can begin transporting the Granular “A” which will become the base.  We compact in lifts not exceeding 6″ at a time while keeping moisture in the medium, this is done to ensure the base is compacted properly.

This is the stage where the final grade is established to allow for a minimum interlock bedding layer!

Bedding Sand Installation for Final Interlock Grade

For the interlock bedding layer we use concrete sand and not stone dust or limestone screenings.  The ICPI recommends that concrete sand specifically be used as some limestone screenings will break down over time.  The screenings also contain finer dust which will retain water leaving the bedding layer saturated and when freezing occurs the water expands.  This expansion is what will cause a patio to distort and shift over time.

The bedding layer is the final grade for interlock installation, after this layer is grading perfectly the pavers can then be installed.

If all the steps above were done correctly your interlock patio should last a long time without have to lift and relay.

Interlock Installation

Ottawa Interlock Driveway

Laying this Ottawa interlock driveway

Now that the hard work is complete we can now begin to install the pavers or interlock.  There are numerous interlock designs, patterns and styles to choose from but the process generally remains the same.  We start by setting up lines to make sure we’re starting straight and square, at this point we will also determine where the best place to have cut stones will be.

A retaining edge is required at all unsupported outside edges of the interlock using 10″ spikes to ensure no lateral movement is possible.



Polymeric Sand & Final Compaction

While it is acceptable to use concrete sand to fill the joints we use polymeric sand.  When using pavers (not slabs) it is required to do a final compaction over the pavers while the polymeric sand is in the joints.  This not only stabilizes the pavers but also removes trapped air from the polymeric sand.

After the final compaction is complete we sweep and blow the excess sand from the stones, a light mist of water is used to retain the sand in the joints.  Once the sand is stable it will form together creating an impenetrable bond with the pavers which reduces weed growth.

Finishing & Clean-Up

An Interlock walkway in Barrhaven

This interlock walkway adds a nice finishing touch to this beautiful composite deck

Once the job is complete we install the necessary sod and finishes to complete the job.  We can also seal the stone at this point if you choose to do so, the sealing product we use does not seal in efflorescence and there for can be applied immediately after the polymeric sand has dried.