You stand on your back terrace and press your boot onto a piece of sandstone. The stone rocks with a loud clack against the hard material under it. Weed stems poke out from wide gaps in the joints.
The mortar crumbled away over the winter. The surface looks uneven. It feels unsafe to step across.
At Village Precision Pros we see this exact scene at houses across Garland County.
A homeowner usually assumes they just need a bucket of cement to patch the empty spots.
Patching over a moving surface only masks a deeper failure. The stones shift because the foundation under them gave way. Water finds an opening and flows under the patio to wash out the bedding material.
The ground beneath the structure expands and contracts with the seasons. We must pull up the problem area to rebuild the foundation. We prepare a solid base before we reset the stones.
The ground beneath your stone patio
Every patio relies entirely on the dirt beneath it. The USDA Natural Resources Conservation Service describes the Carnasaw series as the most extensive soil in Garland County. This soil is well drained with slow permeability.
It carries 50 percent or more clay in the subsoil about a foot down. The clay subsoil sits just beneath the topsoil. Water moves slowly through this dense layer.
The slow permeability means water sits under your patio after heavy rain. Clay holds water for long periods. The soil swells heavily when wet and shrinks deeply when dry. This constant volume change places immense stress on any surface built above it. We must account for this soil movement when we evaluate a failing surface.
The movement below ground eventually cracks the joints above ground. A flagstone patio is built one of two ways. A dry laid patio features stones set on a compacted crushed stone base.
We use a bedding layer of sand or stone screenings directly under the flagstone. The joints receive stone screenings or polymeric sand. This flexible system moves slightly as the clay expands.
A mortared patio requires a completely rigid structure. The mason sets the stones in mortar on a slab. We finish the surface with mortared joints.
A mortared patio is only as sound as the slab under it. The slab must resist the shifting clay beneath it. If you weigh a stone patio or concrete patio in Central Arkansas, understanding these layers helps explain why surfaces fail.
Fixing stones that sink and collect water
Rain constantly tests the boundaries of your outdoor spaces. NOAA’s National Centers for Environmental Information publishes 1991 to 2020 climate normals. These normals put average annual precipitation at the Hot Springs 1 NNE station at 57.18 inches.
That equals nearly five feet of water falling on your property each year. That massive volume of water needs a clear path away from your house. Water always takes the path of least resistance.
A section that sank along one edge points to a washed out base. This specific damage almost always happens where a downspout or roof runoff lands. The roof concentrates gallons of water into one spot.
The falling water carves a deep channel under the stone. It carries the sand bedding away into the yard. We fix the water problem first.
Our crew will move the downspout or regrade the yard. We can also add a drain to redirect the flow. Proper patio drainage design protects the restored surface.
We rebuild the base in compacted lifts. We compact the gravel in thin layers to achieve maximum density.
We then reset the stones over the reinforced foundation. A single stone that rocks underfoot means the bedding beneath it washed out. The crushed stone base might have settled unevenly over time.
A homeowner might try to wedge a shim under the loose piece. A shim quickly fails under regular foot traffic. We lift the loose piece entirely.
We clean out the old material and rebuild the bedding layer. We tamp the new bedding firm. We reset the stone to match the height of the surrounding surface.
Repairing cracked mortar joints
Cracked or missing mortar joints indicate water damage. Mortar joints crack when water enters tiny fissures. The material shrinks over time.
The National Weather Service office publishes freeze normals for the Hot Springs 1 NNE station. The average first 32 degree freeze falls on November 13 based on 1991 to 2020 normals. Water inside an open joint freezes solid during these winter months.
The expanding ice lifts the stone beside it. This frost heave pops the mortar completely out of the joint.
A published repointing method from a stone mason at Devine Escapes provides an excellent fix. We cut the failed mortar out with a grinder and a diamond blade. The diamond blade slices cleanly through the hardest mortar.
We chisel the rest out at an angle to create a clean bonding surface. The angle gives the new mortar a wider area to grip. We clean the joint completely with a blower and a hose.
All dust must leave the gap. A homeowner using a wire brush leaves too much dust behind. The new mortar fails to stick to a dusty surface.
We pack a dry mortar mix into the gap with a tuck pointing trowel. We push the mix deep into the joint to eliminate air pockets. We sponge the joint once when fresh.
We sponge it again at thumbprint dry. A wet mix and over working the surface weaken the joint. We rely on the quality checks that separate long-lived stone work from short-lived stone work to ensure your joints survive the winter.
We leave the surface undisturbed to cure fully. We execute this exact repointing technique under our hardscape and stone masonry service.
Managing tree roots and hollow voids
A stone heaved near a tree means a root lifted it from below. Tree roots grow outward to seek moisture. They easily push through compacted gravel.
The thick roots exert incredible pressure on the stones above them. We lift the displaced stone and inspect the root. We trim the bedding material to fit the tighter space.
We reset the stone level with the adjacent pieces. If the root keeps growing, the patio edge must move back. Sometimes we replace that stone entirely with a planting pocket.
This gives the tree room to expand. The change protects your terrace from further heaving. Adding plants into the gaps gives you new flagstone patio ideas to soften the edge of the hardscape.
A stone cracked over a hollow indicates a void opened under it. The ground settled and left the heavy stone unsupported in the middle. The edges rest on the firm base.
Stepping on an unsupported piece snaps it in half. We lift the broken sections out of the way. We fill the void with fresh aggregate.
We compact the new base material until it stays firm. We check the level against the surrounding area. We then reset a new stone to restore the pattern.
Dealing with deep structural cracks
On a mortared patio you might spot one crack running through several stones. The stones split in a straight line across the surface. The slab underneath cracked due to ground movement.
The slab might have suffered from poor initial construction. The stone on top simply followed the break in the slab. Patching the mortar on top will not hold the pieces together.
The slab will keep shifting. The movement will break the new patch within a few weeks.
Homeowners often try applying a liquid crack sealer. The sealer tears as the slab sections shift on their own. We lift that section and rebuild it dry laid on a compacted base, or replace the slab section.
Both are our work. Rebuilding the damaged section dry laid allows the surface to flex. The flexible base absorbs ground movement without breaking the stones.
Removing weeds and ants from the joints
You will frequently find weeds and ants appearing in the joints. The joint material washes away and leaves open dirt. Ants excavate the loose sand to build their colonies.
Weeds drop seeds into the damp gaps. Both pests quickly take over a neglected surface in Hot Springs Village. We clean the joints out down to the bedding layer.
We remove all organic matter and dirt. We refill the gaps with stone screenings or polymeric sand on a dry laid patio. We completely repoint a mortared patio.
New sand poured over existing weeds fails quickly. The roots remain active below the new filler. The weeds push right back through the fresh sand.
Our crew removes the vegetation mechanically to give the new joint material a clean environment. When you look at how hardscape materials compare over the years, consistent joint maintenance extends the life of the entire structure.
Questions owners ask about flagstone patio repair
What is the best filler between flagstones?
The proper filler depends on the base beneath the stones. We use polymeric sand or stone screenings for a dry laid patio built on crushed gravel. We pack a dry mortar mix into the joints for a mortared patio built on a concrete slab. Applying mortar to a dry laid patio causes the joints to crack immediately.
What do I fill the gaps with?
Gaps require a filler material that matches the existing construction type. We clean out the loose debris to expose the firm layer below. We pack fresh stone screenings into dry laid joints for a flexible hold. We pack stiff mortar into rigid joints to lock the stones to the slab.
How do I repair a patio that has grout on it?
We start by cutting the failed mortar out with a grinder and a diamond blade. We chisel the remaining pieces out at an angle. We clean the empty space with a blower and a hose to remove all dust. We pack fresh dry mortar mix in with a tuck pointing trowel to finish the job.
Why does my patio crack every winter?
Water enters open spaces in the surface during rainstorms. The trapped water freezes solid when temperatures drop below freezing. The expanding ice lifts the material and cracks the stone. We keep water out by maintaining tight joints and ensuring the surface drains correctly.
Schedule your flagstone patio repair
Loose stones and cracking mortar will only worsen with the next rainstorm. Our crew at Village Precision Pros handles these exact repairs across Hot Springs and Central Arkansas. We identify the source of the water damage before we begin any work.
Every project runs in three phases. We start with a consultation on site.
We move to the design and the work. We hand over the finished project with someone to call. We ensure your outdoor living space handles the heavy rain and shifting soil of Garland County.
Call our office at (501) 340-0711 to schedule an inspection. You can also reach us through our contact page to discuss your stonework needs. Our crew works Monday to Friday.
We start at 7:30 and finish at 4:30. We provide a free on site consultation and estimate for all projects.