No-dig footings inside a protected root zone
Set to plan without altering soils inside a tree's critical root zone — the situation Decatur's ordinance is written around, and the one a poured footing struggles with.
American Ground Screw distributor · Intown & metro Atlanta · Serving all Georgia
Denied over a tree's root zone? Set it without digging.
Georgia Ground Screw's Decatur crew drives galvanized ground screws in place of a dug-and-poured footing — built for lots with mature trees, protected root zones, and the Tree Conservation Plan requirements that apply across intown and metro Atlanta.
0 yd³
Concrete poured on site
~1 day
Footings set & load-ready
ESR-4226
ICC-ES code listed
Metro ATL
Based in Decatur, supplying statewide
Told no because of a tree?
Tree & critical-root-zone rules across metro Atlanta, city by city.
Digging a conventional footing means altering the soil inside a tree's critical root zone (CRZ), which is exactly what a city's tree ordinance is written to stop. A driven ground screw doesn't require that excavation, so it's often the more direct path back to a permitted project. The rule is different in every city. Here is what we have confirmed against the ordinance text itself, starting with Decatur.
City of Decatur — Unified Development Ordinance, Article 9, §9.1
- A Tree Conservation Plan is required with any Land Disturbance or Building Permit application for work that could disturb, remove, or alter soils within a protected tree's critical root zone (CRZ).
- Encroachment beyond 20% of the CRZ is prohibited without an approved arborist prescription.
- No land disturbance is permitted within 10 feet of a protected tree's trunk.
- A pre-application conference with the City Arborist is required before submitting a Tree Conservation Plan or a permit application affecting a CRZ (treepermits@decaturga.com).
This is a summary for orientation, not legal or arborist advice — the City Arborist's determination on your specific site and tree governs.
Why a driven screw is often a shorter path
A conventional footing means digging and pouring inside the soil the ordinance is built to protect — which is exactly what triggers the Tree Conservation Plan review, the 20% cap, and the 10-foot no-disturbance zone. A galvanized ground screw is driven, not dug: it displaces a fraction of the soil a footing hole does, and doesn't require the excavation the ordinance is written around.
That doesn't bypass the City Arborist's review — it changes what the review is looking at. Bring us the tree, the plan, and the arborist's notes; we'll tell you plainly whether a driven footing is the fit.
Decatur is where we are based, not the limit of where the rule matters. Four more metro cities have their own tree-protection ordinance, each read against its own text, below. Tell us where the site is and we will work from the rule that governs it.
The rest of metro Atlanta
Where a city's formula differs from Decatur's, the difference is stated.
| City | What the ordinance says |
|---|---|
| City of Atlanta | Code of Ordinances, Ch. 158, Art. II (rewritten by legislation 24-O-1691, effective 2026-01-01): CRZ formula confirmed unchanged by the rewrite — 1 ft radius per inch DBH, adjustable by the City Arborist for documented site conditions; >20% CRZ grade-change counts as "destroy." |
| Sandy Springs | Development Code, Art. 9, §9.3 (Environmental Protection): CRZ = the tree's drip line or 1.25 ft per inch DBH, whichever is greater, to a depth of 3 ft. A Tree Removal Permit is required whenever a Protected (≥18" DBH), Setback, Boundary (≥10" DBH on an adjacent lot), or Landmark tree is removed, or 25% or more of its CRZ is disturbed — whichever comes first. |
| Brookhaven | Code of Ordinances, Ch. 14, Art. III, §14-50/14-52: CRZ = a circle with radius equal to 1.3 ft per inch DBH (the ordinance's own example: a 20-inch tree's CRZ radius is 26 ft). At least 80% of the CRZ must stay undisturbed on a protected tree; a Boundary Tree Agreement is required once proposed CRZ impact reaches 20%; excavating, compacting, or disturbing soil in the CRZ is barred outright, "regardless of the existence or lack of an approved site plan," and can trigger a stop-work order. |
| Avondale Estates | Code of Ordinances, Ch. 5, Art. X ("Residential and Commercial Tree Protection and Preservation"): CRZ = 1 ft radius per inch DBH, the same formula as Decatur and Atlanta (the ordinance's own example: a 20-inch tree's CRZ is 20 ft). A tree removal permit is required to remove a protected tree, or when land disturbance would encroach more than 20% of a protected tree's CRZ; a boundary tree is one with 20% or more of its CRZ crossing onto an adjacent lot. |
Outside metro Atlanta the same reasoning applies, with a local rule in place of these. We install and supply across Georgia; tell us where the site is and we will work from the rule that governs it.
Ground screws vs. poured concrete
Same load capacity. None of the dig, haul, and cure.
A ground screw is a galvanized steel shaft driven into undisturbed soil to a rated depth. Here is how that changes a footing job.
| Criteria | Ground screw | Poured concrete |
|---|---|---|
| Site work | No excavation | Dig, spoil, haul-off |
| Tree critical root zone | Driven, not dug — often proceeds without altering the CRZ | Digging inside the CRZ can trigger a Tree Conservation Plan, or be barred outright |
| Schedule to load | Same-day, load-ready | Days of cure time |
| Sloped, wet, or rocky sites | Works | Difficult |
| Tight or limited access | Handheld or compact drive | Needs truck access |
| Code capacity | ICC-ES ESR-4226 rated | Prescriptive / engineered |
| Removable & reusable | Yes — unthread and relocate | No — demolition |
Where they win
Ten jobs where a driven footing beats a poured one.
The advantage compounds on Decatur's older, tighter, tree-covered lots — a hard site, many footings, or a clock. Those are the projects we take on.
No-dig decks & additions
Footings set to plan without tearing up the yard, then framed the same day. Ideal for Decatur's tighter, tree-covered intown lots.
ADUs, cabins & sheds
A level, load-rated platform on grade for accessory dwellings and outbuildings — including sloped and wooded lots where a slab is impractical.
Solar ground-mounts
Dozens of footings driven fast and to spec, with embedment verified on every screw. Consistent reveal and racking geometry across the whole array.
Buy code-rated screws locally
Contractors source American Ground Screw screws, brackets, and drive accessories from us — code-rated stock held in Decatur, on hand for pickup across metro Atlanta and shipped anywhere in Georgia, with sizing help.
Pergola & patio cover posts, set through a slab
Want a pergola or patio cover where an old concrete patio already sits? We bore through the slab at a diameter that clears the shaft, then drive into the soil beneath it. The patio stays where it is, the demolition bill disappears, and there is nothing to re-pour.
Level bases for prefab sheds, carports & playhouses
A delivered building needs a level, load-rated base before the truck arrives. Screws give one on a sloped or wooded lot in a morning, with no pad to pour and no waiting on a cure. We work with dealers as well as owners.
Fence, sign, light pole & flagpole posts
No bags, no mixing, no water, no cure. A driven post foundation is set and loaded the same hour, which matters most when there are dozens of them and a schedule.
Lots a concrete truck cannot reach
Narrow intown lots, no side access, a finished lawn nobody wants rutted. The equipment is handheld, so the footing arrives where a mixer never could — and there is no spoil pile to haul out afterwards.
Speed-critical projects
When the schedule cannot absorb a concrete cure, driven footings keep trades moving. Signage, canopies, modular units, and phased site work stay on the critical path.
Photo Deck footing beside a protected tree — screw set inside the drip line, no root disturbance.
Common questions
What people ask before they call.
Most of these arrive from someone mid-permit, mid-quote, or mid-argument with a site that will not cooperate.
Can you build a deck without concrete footings in Georgia?
Yes. A galvanized ground screw is a code-listed footing carrying the same design loads as a poured pier. Every screw is driven to a rated depth in undisturbed soil, and because nothing has to cure, the deck can be framed the same day the footings go in.
My permit was flagged over a tree's root zone. Now what?
This is the situation we see most. A dug footing removes soil from inside the critical root zone; a driven screw displaces it instead, without trenching or auguring through the root plate. Whether that satisfies your reviewer depends on the ordinance and the arborist, and those differ across metro Atlanta — the table above sets out what each jurisdiction actually requires.
Can footings go through an existing concrete patio?
Yes. We bore through the slab at a diameter that clears the shaft and drive into the soil beneath. The patio stays, which is usually the point: a pergola or cover can go up over a slab nobody wants to demolish and re-pour.
What if a concrete truck cannot reach the site?
Then this is a straightforward job rather than a difficult one. The drive equipment is handheld, so it goes down a side yard, through a gate, or across a finished lawn. Nothing is excavated, so there is no spoil pile to barrow out afterwards.
How long does an installation take?
A typical ten-screw residential job is a single morning. There is no cure period, so your framing crew is not waiting on us and does not lose a day to the calendar.
What does it cost?
Pricing is per screw and turns on size, count, and how hard the site is to reach. Send us the site and the load and we will tell you whether screws are the right call — including when they are not, which happens on open, easily dug lots where a poured footing is simply cheaper.
Why it holds
Driven to a rated depth in undisturbed soil, and listed to code.
Each screw is driven to an embedment depth that corresponds to a rated bearing capacity for the soil it sits in. There is no forming, no rebar, no waiting on a pour — and no excavation to account for on a Tree Conservation Plan. The listing under ICC-ES ESR-4226 gives your plan reviewer and engineer a documented capacity to design against.
- Hot-dip galvanized shaft and flights for corrosion protection below grade.
- Embedment logged per screw — the verification ESR-4226 calls for.
- Removable and reusable — unthread and relocate without demolition.
Photo A driven screw at final grade, ready for the beam.
Send us the site — including the tree. We'll tell you if screws win.
Plans, a sketch, or a few site photos are enough for a first-pass quote. Straight answer either way — including when concrete is the better call.