We’ve all seen it, sometimes it’s obvious and looks horrible. Other times you can’t quite put your finger on it but something is off. In either case it could have been prevented by following the steps below. We’re talking about pavers that look bad. So if you are about to try a paver project yourself or are new to the trade – follow these steps below for surefire success.
- Dig deep because 4” of base just won’t cut it in cohesive soils. First how do you know if you have cohesive soil, easy bring it to get tested. For a small fee - around $200 - they will tell you the gradation and standard proctor density of the soil. Gradation is the makeup of the soil and standard proctor density is a measure of how “tight” they were able to compact the soil in the lab. If you have more than 1/3 clay it’s time to call a professional and have the soil amended by pounding huge chunks of stone into the soil to stiffen up the sub base. And my company never uses less than 8” of base material, 12” for driveways.
- Don’t use a demolition tool for an artist’s touch; pick them up to make them look right. From about 20 feet away they will both look the same but up close there is no competition. A demo saw is a quick and dirty way of cutting an edge or soldier course. I’ve seen it done time and time again by landscaping companies right here in Orange County NY. It sure is faster and that’s great but in the end I’d rather have quality - period.
- A wedge is for holding a door open not for curves. This is got to be the king of being lazy, you need to make a soldier course around a curvy patio or coping on a pool so what do you do. On a curve the only way to make it look good is to cut EVERY one. Anything else will look chunky and you will inevitably be left with a tiny wedge that you need.
- Go big or go home, if you can lift it – it won’t compact anything. Compactors come in roughly 3 flavors vibratory, ramming and kneading. I have yet to have a soil gradation test come back where I was able to use my vibratory plate compactor. Rammers or “jumping jacks” as we call them and trench rollers are the only approved ways of compacting cohesive soils. One thing all the good compactors have in common is heft. The trench roller below weighs over 3000 pounds!
- I think it’s done. O.K. we talked a lot about compaction, but how do we know when we are done. The only real way is to test it. A simple Dynamic Cone Penetrometer will do the trick and save you the headache of re-doing things down the line. Industry standard is 98% Standard Proctor Density or a CBR (California Bearing Ratio) of 150. Let’s face it if you don’t test you are just guessing and you’re bound to guess wrong at some point.
- Bond lines – don’t have them running or in a basket. They don’t call them interlocking for nothing. Pavers that have long continuous bond lines are prone to failure. That line is like creasing a piece of paper and is considered a weak point. In a running bond or basket weave pattern there are loads of long straight lines. However much you may like that pattern do yourself a favor and stay away unless you pour concrete underneath.
- You got to keep em separated. The base and sub-base that is. A geotextile such as Mirafi 500x will do just fine. This is basically a layer of tough fabric that keeps the sub-base from contaminating the base while allowing water to pass through. Check out the PDF on it here.
- Never lose your edge. Pavers need something at the edges to keep them from moving on the horizontal plane. You can use all sorts of things to do this. A house foundation will do just fine on a patio or walkway that meets the house. Belgium block set in concrete or just concrete by itself will also work great. If none of those appeal to you or are just not an option specialty products are available to do this. Paver edge is sold in either aluminum or some form of plastic. In either case use bright spikes not galvanized. You need the spikes to rust and “grab” onto the soil.
Here we used a retaining wall as one edge and aluminum edging where the pavers meet the gravel
There are countless other tips and tricks of the trade that I have learned over the years but these 8 should get you started.