Timber Retaining Walls in Sandy Springs, GA

A timber wall is a practical way to hold back soil on a gentle slope, and it suits the wooded lots common around Sandy Springs. We build new timber walls, repair sound ones and tell you honestly when an old wall can't be saved. Every wall we build gets gravel backfill and a drain, because wet clay is what pushes most wood walls over.

When a timber wall is the right choice

A timber retaining wall is built from pressure-treated landscape timbers or larger square posts. They are stacked and tied back into the slope. On a modest grade it is usually the quickest and lowest-cost way to hold back soil, and on a wooded lot it can look more natural than stone or block.

Timber works best for shorter walls: a raised bed, a terrace across a sloped back yard, or a low wall along the edge of a driveway. If you need a tall wall against a steep bank, or a driveway or patio will sit above the wall, we usually recommend block or boulders instead. Wood wears out over time, and the bigger the wall, the more a failure costs.

If we think timber is the wrong material for your slope, we will say so plainly.

What to look for in an existing timber wall

Most timber walls show warning signs before they fail. Walk along yours and look for these:

One soft timber can be repaired. If the whole wall is leaning, the problem is structural, and a lean usually gets faster once it starts.

• Lean: the top of the wall tilting toward the yard, even slightly. Hold a level against the face if you are unsure.
• Soft wood: push a screwdriver into the timbers near the ground. If it sinks in easily, rot has started.
• Bowing: a bulge in the middle of a run, where the timbers push outward between the corners.
• Gaps and soil loss: dirt washing out between the timbers or from the base after rain.
• Loose spikes: steel spikes or rebar backing out of the timbers, or rusted through.
• Sagging ground behind the wall: a dip or crack in the soil on the high side, which often means the backfill is moving.

What usually causes a timber wall to fail

Water causes most failures. When rain soaks the soil behind a wall and can't drain away, the soil gets heavier and pushes harder. A wall built without gravel backfill and a drain pipe takes that extra pressure in every storm.

Rot comes second. Pressure-treated wood resists decay, but timbers that sit against wet clay still break down over the years. Rot starts at the bottom course and anywhere soil stays damp against the wood. Termites and carpenter ants then move into wood that is already going soft.

The third cause is poor construction. These are the shortcuts we see most often:

• No deadmen. A deadman is a timber set at a right angle to the wall and buried in the slope to anchor it. Without deadmen, the wall relies on its own weight, which is rarely enough once it is more than a couple of feet tall.
• No base. Timbers laid straight on topsoil settle unevenly.
• Timbers stacked straight up instead of each course stepping back slightly into the hill.
• Timbers rated only for above-ground use instead of ground contact.

Repair or replace

If the wall stands straight and only a timber or two has rotted, a repair is often sensible. We can cut out and replace the damaged sections, re-spike loose courses, and clear the drainage at the base or add it if there is none. On a wall that is otherwise sound, that keeps it working for longer.

Replacement makes more sense when the whole wall leans, when rot runs through several courses, or when there is no drainage behind it at all. Patching a wall like that usually means paying twice. If the wall has to come out anyway, ask whether timber is still the right material. Many homeowners replace an old timber wall with block, which lasts longer and needs less upkeep. We can price both options so you can compare.

If the wall leans toward a walkway, a driveway or a neighbor's property, don't wait for it to get worse. Keep people and cars away from it and give us a call.

How we build a timber wall

Most of what makes a timber wall last is hidden once the job is done. Here is how we usually build one:

Taller walls, and walls that hold up a driveway, a building or another wall, may need an engineered design and a permit. We check this before we quote, not after work has started.

• Dig a trench and lay a compacted gravel base, so the first course sits level and drains.
• Set the bottom course partly below ground so the wall can't slide forward.
• Use pressure-treated timbers rated for ground contact, with each course set back slightly into the slope.
• Pin the courses together with long spikes or rebar driven through pre-drilled holes.
• On walls tall enough to need them, install deadmen at regular intervals, anchored in undisturbed soil behind the wall.
• Lay perforated drain pipe at the base and backfill with clean gravel. Filter fabric goes between the gravel and the native soil so the clay can't clog it.
• Plan where the water goes, so the pipe drains somewhere sensible and not onto the lawn below.

What a visit involves

We come out, walk the slope with you and look at the existing wall if you have one. We check how tall and long the wall needs to be, how steep the slope is, where water runs in a storm, what sits above the wall (lawn, patio or driveway), and how a crew and materials will get to the spot. Access matters on a wooded lot, because timbers and gravel often have to be carried in by hand.

After the visit we send a written estimate. It says what we would build and why, including the drainage. If a repair will do the job, we tell you. If we think block or boulders would work better, we explain the difference and let you decide.

Timber walls in Sandy Springs

Much of Sandy Springs sits on rolling Piedmont hills, and many lots slope down toward a creek or the Chattahoochee. Back yards are often steep, and timber walls have long been a common way to make flat space for a patio, a play area or a garden.

The soil here is red clay. It holds water, drains slowly and swells when wet. That puts a lot of pressure on a wall during long rainy spells and the heavy summer thunderstorms we get here, so drainage goes into every wall we build. Humid summers keep wood damp for weeks at a time, so rot usually starts at the bottom course and in shady spots under mature hardwoods.

Many homes in the area were built decades ago, and the original timber walls on those lots are often near or past the end of their life. If you have just bought a house with an old wood wall, have it checked before it starts to lean.

We also work in Dunwoody, Roswell, Brookhaven and nearby towns, where the slopes and clay are much the same.