how to extreme

Build Your Own Patio

Construction How-To, Outdoor Living, Patios January 1, 2007 Matt Weber

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A step-by-step look at building a brick paver patio. Winner of the 2007 Golden Hammer Award in the Internet category from the National Association of Home & Workshop Writers.

My mom wanted a patio. She wanted a nice, shady place beside her house to relax, read, sip lemonade and host the occasional barbecue. This meant Dad and I had a new project on our hands.

The ground next to the house—the proposed patio location—sloped toward the rear of the yard. A sloped patio meant spilt drinks, toppling chairs and potential lawsuits, so we opted to build it with a flat surface. This meant we would have to build up the rear end of the patio to match the higher ground elevation at the front of the house.

To support the patio, we used a segmental retaining wall system. To compensate for the slope, our design required two courses of wall blocks topped with a single course of cap blocks at the rear end of the patio. At the front, we only needed a single course of cap blocks, which were solid, flat and 4 inches thick. The single course of cap blocks in the front placed the patio surface just a couple of inches above the ground to prevent mud and rainwater from collecting on top. The number of block courses between the rear and front of the patio decreased as the wall progressed uphill.

Once complete, the retaining wall gave us a sturdy, flat perimeter for the patio. We then filled it with dirt and finished the surface with brick pavers. Sounds simple enough, right? Well, as we learned, there’s a bit more to it than that. Here’s what happened.


Laying it Out

The first step is to determine the location of your patio. Keep in mind the orientation of other buildings and landscape features in relation to the patio, as well as accessibility to shade, sunlight, etc. We made sure to keep our layout square with the side of the house, with the front of the patio aligned with the front of the house.

As you can see in the diagram of the retaining wall (above), you then figure out how many courses you need, based on the size of the blocks in relation to the height of the slope you need to overcome.

The wall blocks we used were 8 inches tall, plus an additional 4 inches for each cap unit. As you calculate the height, there are two additional factors to keep in mind: First, take into account the 6-inch foundation bed of crushed rock beneath the blocks. Also account for the first course of blocks to be buried 4 inches below grade. These measurements will figure into your digging depth and overall wall height.

When calculating your patio dimensions, first determine the finished top surface of the patio and plan in reverse. We wanted the front edge of the patio flush with the front wall of the house, which gave us our starting point. We also wanted the surface of the patio (i.e. the surface of the front cap block) to be just a couple of inches above the ground, which gave us our starting elevation. So, at a spot that was even with the house, we dug a trench, added enough crushed-rock base for a single cap unit to sit on—with the top just above ground—and used that cap unit as our reference point. We then used a Craftsman laser level positioned on that cap unit to shoot a level line to the opposite end of the proposed patio location (the rear of the yard with the deep slope). From the laser line, we measured downward to determine the height of the wall, and in turn, how many blocks we would need to achieve that height.

A cap block at the front of our patio served as our starting point for the layout.