Base Prep- Starting Strong
The true measure of an excellent Hardscape install isn’t in the overall appearance of a completed project, but rather how it holds up to weather, traffic, and time. Excavation depth, subsoil type, base material, moisture, and compaction are all contributing factors to base preparation. A strong grasp of what it takes to make a project last comes from experience combined with the business mindset that each project should last for many, many years.
Time tells all. Did you use a hand tamper in the corners that the plate compactor couldn’t reach? Did the pavers settle out in spots where the base prep is thinner? Is there stand- ing water causing a minor depression in the surface to get worse and worse?
Taking the time to increase the depth of our excavation if the sub soil isn’t ideal, or even adding a layer of geotech cloth to stabilize the base, are the first key steps to success.
If your project has you digging in dark soil with visible organic matter i.e. root, leaf, or plant material, then you need to dig deeper until you see a visible colour change to more of a clay-like or load bearing soil type. These decisions can be difficult when worried about the cost of extra excavation and additional road-base, so pricing your base prep accordingly to cover the cost of doing it exceptional- ly well is key.
What amount of compaction is ideal? What do we need to do to achieve our target % of Proctor Density? It’s literally hard to tell with- out renting the special equipment required to measure the density of the base layer. More often we use standard rules to achieve an acceptable level of compaction. These rules include using an appropriately sized plate compactor (bigger is better if space allows for it) only adding and compacting layers of 4” or less at a time, and using patterns of compaction to be sure that every square foot receives the same amount of compaction force. The harder and more consistent the base layer is from the bottom all the way to the final layer, the longer your finished surface will stand the test of time.
Take your base prep to the next level by do- ing an accurate screed of the final layer. Use your string-line setup with a 2”x4” notched out to the appropriate height (taking compaction into account), or set your screed bars for the final layer of road-base. This extra step will improve the accuracy of any project and make sure that as the project settles slightly over time, it settles uniformly and looks perfect for as long as it should.