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"My front porch was falling to pieces and wouldn't have lasted another winter. I contacted Dave at Highbury Stone and his guys came in and repaired all the loose stone and made my porch look like new again."

by Barbara, Burlington

Things to know about interlock installation

  • What is the correct depth to excavate for a interlock project?
    This is a tricky question to answer because there are a few key factors that contribute to what the correct depth of excavation should be.

  • Soil Type: For example, if the project is to be installed onto a sandy soil area then we wouldn't have to excavate to the same depth as we would a similar project installed onto a clay foundation (Clay requires a deeper excavation because it retains water which contributes to the base heaving up during winter cycles; whereas sand filters the moisture away more efficiently).

    Type of traffic: Is the area to be used for vehicles or just pedestrian traffic? A driveway for example, would require a deeper excavation than a walkway or patio. The reason for this is because a driveway used by vehicles would require more base material to ensure stability and avoid sinkage.

    Note: At Highbury Stone we excavate approximately 11 inches for all pedestrian projects and 16 inches for all vehicle traffic projects regardless of the soil type, just to ensure stability for every job.

  • Are all interlock stone equal?

  • Some interlock stone is basic without any added features or the latest technology which is just fine if thats all you require or are working within a budget.

    Other types of stone can have some added features. One example is Endura color® which has non-fading colour pigments added whilst in the manufacturing process in order to prevent fading under extreme conditions.

    Some interlock stone have added minerals such as granite and quartz to create an incredibly durable stone.

    These are just two features that, although may be more expensive, can add a higher quality to the look of your project and preserve the life of your stonework.

Correct procedure for interlock installation

    For example, if we were to install an interlock project for pedestrian traffic only onto a clay foundation, the steps are as follows:

  1. The area is first marked out and then excavated approximately 11 inches.
  2. Approximately 7 inches of ¾ inch crushed limestone base material is installed into the excavated area, compacting every 2 inches to ensure stability.
  3. Then approximately 1 - 1½ inches of fine crushed limestone (screening) or sand is installed as a levelling base.
  4. The interlock stone is installed onto the levelling base once the grade has been set (always ensuring to slope away from the house approximately 1/8 inch slope to every 1 linear foot).
  5. After all the stone is installed and all the cuts are made, an edging system is installed around the perimeter of the project to prevent the stone from pushing outwards.
  6. The new interlock area is compacted to level and stabilize the stone.
  7. Finally, polymeric sand is swept into the stone joints to prevent weeds and insects. The area is lightly hosed to harden the sand.

  8. Note: It is very important to excavate to the correct depth and compact the base every 2 inches in order to ensure no sinkage.

Winner Homestars Best of 2017


"I was extremely impressed with Highbury Stone's professionalism. Both Dave and his crew, were easy to work with, polite and did a great job in a timely fashion from start to the final clean up."

by Candice

"Excellent work done on our walkway! We are thrilled with the results and found Highbury Stone to be very professional, organised and affordable. Would highly recommend!"

by Stephanie