Instead of Paying for a Flagstone Patio, He Built This One Himself With Zero Experience
Building a flagstone patio was new territory for Reddit user u/PhrygianDominate. He had no prior experience laying stone, yet he took on the backyard project himself, starting with a patch of grass and soil beside the existing concrete patio.
Mariposa slate flagstones became the surface, with decomposed granite beneath and between them. The stone made the job harder than a patio built from uniform pavers because individual pieces ranged from 1.5 to 4 inches thick.
Part of the material had another advantage: about half of the flagstone was already buried beneath the grass in the backyard. He bought another three-quarters of a pallet from a local seller for $300, then used every stone he had to cover the new patio area.
He Cleared the Grass to Make Room for the Patio
Work started by removing the grass and clearing the soil between the existing concrete patio and the back fence. The excavated area created the footprint for the new stone surface while leaving the concrete slab in place.
Getting the ground down to the right depth mattered because the finished patio needed room for both the decomposed granite and thick slate. With stones that differed by several inches, the base could not sit at one fixed depth beneath every piece.
String Lines Marked the New Patio Area
Once the grass was gone, string lines defined the edge where the patio would meet the remaining lawn. The existing concrete and narrow planting beds formed the other boundaries.
The cleared soil also exposed the size of the project before any base material went down. Instead of extending the concrete, he was preparing the space for an irregular stone surface that could work around the existing yard.
Decomposed Granite Created the Base
Piles of decomposed granite were spread across the excavated ground before the flagstones went in. The material would form the base beneath the slate and fill the spaces between the finished stones.
This stage gave him material to add or remove beneath each flagstone, an important part of dealing with pieces that varied from 1.5 to 4 inches thick.
He Spread and Leveled the Granite Before Adding Stone
After the piles were distributed, the decomposed granite formed a broad, flat layer across most of the patio footprint. A board and string line helped maintain the planned edges while the material was worked into place.
The smooth base did not mean every stone could be dropped on top at the same level. Each irregular piece still needed adjustment once the slate installation began.
The Flagstones Went Down From the Existing Edges
Large pieces of Mariposa slate began filling the area beside the existing concrete and along the back edge. Rather than creating rows, the irregular stones were fitted together according to their natural shapes.
The wide range in thickness became one of the hardest parts of the project. Leveling was, in the creator’s words, “a pain,” since neighboring pieces could differ by inches.
Every Stone Needed Its Own Position
As more flagstone covered the base, the patio began to take shape. Large slabs filled broad sections while smaller pieces occupied spaces that remained between them.
He later said tighter joints would have been possible with more cutting and sizing, but he ran out of stone and used every piece he had.
Decomposed Granite Filled the Irregular Gaps
Once most of the slate was positioned, decomposed granite remained visible between the stones. The material filled gaps that varied in width because the flagstones were left close to their natural shapes rather than cut into matching edges.
He planned to see how the decomposed granite performed in his hot, dry California climate before changing the joint material.
The Dirt Patch Became a Full Flagstone Surface
By the end of the installation, slate covered the former patch of grass and bare soil. The mix of brown, rust, gray, and charcoal tones gave the patio variation that manufactured pavers would not produce.
The project was not finished with the stonework. Plans included replacing the back fence and adding plants and trees around the patio.
Water Brought Out the Slate’s Color
With the surface wet, the differences between the Mariposa slate pieces became much more visible. Rust-colored slabs sat beside deep gray, brown, and blue-toned stone, while the decomposed granite formed narrow lines around each piece.
What began as an excavated section of backyard now had a defined hardscape surface built around material the homeowner installed on his first attempt.
From Grass and Dirt to a Patio Built by Hand
The before-and-after view shows how much of the yard changed without replacing the surrounding concrete or rebuilding the entire space. Grass and soil gave way to a flagstone patio connected to the existing covered area.
The stonework is also only the start of the plan. A Corten steel fire pit with Adirondack chairs is intended for the patio, followed by the new fence and planting around it.
Would you take on a flagstone patio with no experience, or is this one backyard project you’d hire out?
Image credits to Reddit user u/PhrygianDominate.