This client in Oakville reached out to us because their paver patio and steps had completely settled on this raised patio. This project was less than 5 years old and was already showing signs of the major settling causing pooling of water on the patio and the steps completely leaning forward. We came into assess the situation and see what we could do for them. 

After lifting one paver we noticed the problem. The contractor had used stone dust for the entire base of this project. Stone dust should never be used on any paver project. It is also referred to as limestone screenings or chipped dust. This is a fine chip all the way down to fines which is a sandy mixture of limestone. It is also the leftover result of crushing stone to make various types of aggregate at quarries who then try to sell this byproduct. This means it is a very cheap product and also is installed to create a cheap and product for clients. It is not free draining so the water sits in the base which causes multiple problems for paver projects. This includes heaving and settling after Winters, the degrading of pavers, and presence of efflorescence which is a white powdery residue caused by moisture. Contractors should never use stone dust in their projects especially for the entire base as we see in this project. 

We began by lifting all of the pavers, cleaning them, and setting them off to the side. We then had to excavate all of the stone dust from this project and dispose of it. This is was a lot more than what we had anticipated as we had assumed that the stone dust was just used for the 1 inch bedding layer. Instead what we had to do was remove a full 8 inches on the lower landing of this raised patio and a full 24 inches on the upper landing. When we quote  a project for our clients, we stick to that quoted price and what is in the scope of work. For this project we had quoted the removal of 1 inches and because we did not look beyond that 1 inch layer, we stuck to our quote for our client and did not have them cover what we had missed. This is our duty as a professional and how we ensure that our client knows what they are going to pay for their entire project before they agree to it.

We then replaced that base material with a 3/4-inch clear stone (no fines). This is an appropriate base aggregate for pavers and allows the water to freely drain through it. It is also referred to as an open graded base. We also separate our base from our subsoil using a non-woven geotextile. This ensures that base will not mix with our subsoil over time. We compact our base material in lifts or height of base material that is appropriate to our compactor. We then lay a layer of biaxial geogrid which acts to stabilize our base material that we place on top of it. This is an inexpensive way to help stabilize that entire system and prevent future settling. We continue compacting our base up until the final portion which is the 1 inch bedding layer where we use a 1/4-inch chip clear stone (no fines) or HPB (High Performance Bedding). 

We set our screed bars 2 inches below the top of our wall around this raised patio and put a slight crown on the pavers to ensure any water works its way off of the patio towards the wall block and off of the entire raised patio so that there is no future pooling. We set our screed bars 2 inches lower than the top of the wall block of the raised patio because that final 2 inches is for the paver height (in this case these pavers are 2 inches high). We lay our existing pavers and sweep in polymeric sand. This is sand that remains flexible but solid in our system after we activate it with water. We also need to compact that sand down to the bottom of the joint using a vibratory plate compactor to ensure we have a full depth of polymeric sand through those joints. 

We also had to reset the steps in this raised patio. This includes removing the step blocks, cleaning off the adhesive that is on the step blocks, and re-leveling on our base. The final result is the same patio that the client should have received from their contractor if they had constructed it correctly. Unfortunately the wrong contractor was hired in the first place which is why clients should understand what they are paying for when they compare quotes from contractors. The cheaper price usually means cheaper material and installation methods in order to save money. You get what you pay for with the end result. 

When talking to potential clients about their options for a lift and relay, we let them know what it would cost to lift and relay the pavers by removing the 1 inch bedding layer and relaying the pavers, what it would cost if we were to lay new pavers on the existing base without our warranty as we did not prepare that base, and what it would cost to do a complete new project. In this scenario, the client had no choice but to replace the entire base otherwise they would have been back in the same situation in less than 5 years for their patio.

The end result is a paver patio that is prepared properly for our client to enjoy for the long term with our full warranty because we replaced the base in its entirety.