Thank you for taking the time to learn about what goes into your interlock project! Both owners Denis Cashman and Raymond Logie have proudly attended and passed the ICPI course, and continue to educate themselves by attending yearly industry seminars to learn the newest and best industry practices.
When we arrive to start a project, we always come prepared with dig locates to ensure there is no underground infrastructure damages. We then mark out the area and start digging!
On a typical driveway base, we dig to a depth of 18"-20".
Residential walkways will see an excavation depth of 12"-14"
We always over dig the excavation area to allow for "overbase" for the interlock edge restraint to anchor into.
Once excavation is complete, we lower our plate compactor into the excavated area and begin compacting the subsoil below the interlock base. This is done to solidify the sub-base for the entire interlock footprint.
Once the sub-base has been compacted, we install a layer of greenline woven geo-fabric. This fabric wraps up all edges of the excavation area and has a minimum overlap of 12". This fabric prevents soil migration into the compacted base and creates a "trampoline" effect for the compacted base.
After the geo-fabric has been installed, we can begin the compaction stages. This is the part of the compacted base which takes the longest. The compaction of the base is done in what we call "base lifts". Each lift is done in increments of 3"-4".
Once the 3"-4" of granular A is moved into the area, we add the pr ratio of water and start compacting. We compact the base until it has reached maximum compaction for that lift.
This step is repeated until the base is within 4" of interlock height.
This is what a compacted lift looks like.
Half way through the compacted base stage, we sandwich a layer of DriveGrid between the Granular A. DriveGrid is an engineered triangular mesh system which acts as a three dimensional load distributor.
We use DriveGrid to help mechanically stabilize the base, reducing potential settling and rutting, give you the client, and us the installer both peace of mind. In certain applications, two or three layers of DriveGrid can be installed.
Once our lifts have reached a few inches below interlock height, we set our grades and elevations using a system of heavy duty pipes.
Once set, compaction occurs between the pipes, they are then doubled check for accuracy upon compaction completion.
After final inspection of the grades/elevations, we install a min. 1" layer of washed concrete bedding sand. We strive on only using washed concrete sand as our bedding layer as it complies with the ICPI standards of installation, and manufacturer warranties. Limestone Screenings (commonly known as 'Stone Dust') is not a viable source or replacement for a bedding layer
Once the bedding layer has been set, pipes are removed, the area in which they were is filled, and interlock installation can begin. Using a system of string lines, we ensure that everything is nicely inline and square. The proper cuts are made (where applicable) and a plastic edge restraint is installed on the outer edges into the "overbase".
Upon final inspection of the cuts, we then move the installation of the polymeric sand. This is done over two steps. First we fill the interlock gaps to the top, then compact with a small plate compactor which has a polyurethane protective mat. Once the interlock has been compacted, we do a final sweep. After making sure there is no residual polymeric sand left on the interlock, we add water, activating the glue agent within the sand.
You can rest assured that you have received a professional interlock installation to enjoy for many years to come!