He Used 3,500 Pounds of Flagstone and Ended Up With a Backyard Fire Pit That Looks Professionally Built
Grass covered the entire space before work began. Four months later, a 15-foot flagstone patio, wood-burning fire pit, and curved retaining wall occupied the same part of the backyard. The build required about 3,500 pounds of flagstone for close to 200 square feet of stonework.
Reddit user u/Filler_of_needs built the project from the ground up, from excavation and base preparation to fitting the irregular flagstones around the center pit. Cutting and arranging the stone took the most time, since each slab had to be tested against the pieces around it before being trimmed to fit.
The finished space bears little resemblance to the open lawn shown at the start. Stone replaced the grass, the curved wall followed the patio perimeter, and a fire pit became the center of a new backyard gathering area.
He Started With a Circle Cut Into the Lawn
Work began by marking a large circle in the grass and removing the turf inside it. The planned flagstone section measured 15 feet across, with another foot around the perimeter for the retaining-wall area.
The circular footprint established the size before excavation began, rather than letting the amount of available stone determine the final dimensions.
Excavation Made Room for the Base and Wall
Soil came out across the full circle to make room for the patio foundation. The excavation also extended below the finished flagstone elevation to accommodate the lower courses of the retaining wall.
The builder later said he may have dug deeper than needed. His finished structure included about five inches of base, an inch of leveling rock beneath the flagstone, and two retaining-wall courses below the patio surface.
Crushed Rock Filled the Excavated Circle
Rock replaced the removed soil and created the foundation beneath the future patio. The base extended across the circle before the flagstone installation began.
Drainage was built into this lower layer as well. Beneath the fire pit, six to seven inches of rock allowed rainwater to drain through the structure. The creator reported no standing water after several stretches of multi-day rain.
Retaining Blocks Established the Outer Wall
Concrete retaining blocks began forming the curved perimeter while the center remained open for the flagstone. Lower courses sat below the future patio surface, tying the wall into the excavated base.
The blocks used here were a budget choice. After finishing the project, the builder said he would have preferred a more natural-looking retaining-wall block if he were doing it again.
The Flagstone Installation Started at the Edge
Irregular flagstones began covering the prepared base inside the wall. Unlike rectangular pavers, the slabs did not arrive in a pattern that could be repeated across the circle.
Each piece had to work with the shapes already in place. That meant setting a slab down, checking its curves and size, lifting it again when needed, and searching for a better match.
Each Flagstone Was Cut to Fit the Pieces Around It
Fitting the flagstone became the longest part of the four-month build. The creator used a grinder with a masonry blade and worked on one slab at a time.
That process turned 3,500 pounds of separate stone into a continuous surface without forcing the patio into a uniform paver pattern.
Stone Gradually Covered the 15-Foot Circle
As the installation moved inward, the original base disappeared beneath a mix of large and small slabs. Narrow joints separated the pieces while the curved retaining wall contained the patio around the perimeter.
The amount of flagstone was calculated from the planned 15-foot diameter. In total, the builder used about 200 square feet of stone measuring roughly 1 to 1½ inches thick.
A Wood-Burning Fire Pit Filled the Center
Retaining-style blocks formed a second circle at the center of the flagstone patio, creating the wood-burning fire pit. A metal insert sat inside the block ring to contain the fire.
The insert was purchased rather than fabricated, while the surrounding masonry became part of the larger DIY build.
Crushed Stone Filled the Flagstone Joints
Once the slabs were in place, No. 12 rock went into the spaces between them. Crushed-granite chicken grit followed to fill smaller voids left between the larger aggregate and stone edges.
The joint material preserved the irregular outlines instead of hiding them beneath mortar, leaving each flagstone visible within the finished surface.
The Curved Wall Framed the Patio
Additional block courses brought the perimeter wall to its finished height. Cap blocks created a broad top around the curve, separating the flagstone area from the surrounding lawn.
The result turned the outer structure into more than an edge for the patio. It gave the circular space a defined boundary while keeping the center open around the fire pit.
3,500 Pounds of Flagstone Replaced the Grass
Once the construction debris and tools were gone, the scale of the change became clear. The open patch of lawn had become a stone-covered gathering area with a central fire pit and curved wall.
The finished flagstone area spans 15 feet across and contains about 3,500 pounds of material, all fitted within the circular footprint planned before the first section of grass came out.
Four Months of Work Changed This Part of the Backyard
From the house, the finished patio reads as one complete feature rather than separate additions made in stages. The flagstone pattern draws toward the center fire pit, while the wall follows the same circular shape around the outside.
The project took four months from start to finish.
The Before and After Shows the Full Transformation
The starting photo shows uninterrupted grass where the patio now sits. The finished view shows how excavation, base preparation, stone cutting, wall construction, and the fire pit changed that same footprint without taking over the rest of the yard.
Would you take on 3,500 pounds of flagstone yourself, or is fitting that much irregular stone where you’d call in a contractor?
Image credits go to u/Filler_of_needs.