Concrete Pool Crack Repair in Dacula — Structural vs. Cosmetic

A homeowner off Hamilton Mill Pkwy called us last April with a phone photo and one question: “Is this crack something to worry about, or can I just ignore it?” The honest answer — one you rarely get from a pool company — is that the crack itself tells you almost nothing. The width tells you something. The behavior over time tells you more. And what’s happening behind the plaster tells you everything.

Her pool was a 1998 gunite build in one of the original Hamilton Mill sections, sitting on a lot that steps down roughly 8 feet from the back of the house toward a tributary of the Alcovy River. The crack ran vertically from the tile band down to waterline minus 14 inches, on the shallow-end wall closest to the house. She had seen it first in March. By April it looked — to her — a little longer.

We drove out the next morning with a feeler gauge set, a flashlight, and a dye pellet. Forty-five minutes later we had a diagnosis: a moderate crack, 1/16″ wide at its widest point and 1/32″ at its narrowest, active but slow. It did not need a full structural rebuild. It needed epoxy injection at five ports, local plaster patching across an 18-inch section, and a follow-up measurement in 90 days to confirm it had stopped moving. Total bill: roughly $1,800.

That “right-sized” repair is only possible if you classify the crack correctly. Over-treat it and the homeowner writes a check for $6,000 of work they didn’t need. Under-treat it and the same crack shows up 18 months later at twice the width, with saturated soil behind the shell and a resurfacing bill attached. This post is the exact diagnostic sequence Primetime uses on every crack call we take in Dacula — and why it matters that we log, measure, and photograph every one.

Crack Classification — The Four Categories That Change the Repair

The word “crack” is almost useless on its own. A hairline fissure in plaster and a wall crack leaking 400 gallons a day are both “cracks,” and a homeowner has no reason to know the difference until someone with a gauge set shows up. Here is the four-category system we apply on every inspection.

HAIRLINE — less than 1/32″ wide

Cosmetic cracks, almost always confined to the plaster layer itself. Plaster is a 3/8″ to 1/2″ cementitious coating bonded to the gunite shell underneath. As the pool fills and empties with temperature swings and calcium migrates through the matrix, a hairline check craze is nearly inevitable over a 10–15 year surface lifespan. Hairlines running in irregular networks on the floor are called “check cracks” — not a structural issue.

The diagnostic tell: a standard 0.002″ feeler blade will not seat into a hairline. Dye released next to it stays put — there’s no active water movement pulling it in. The plaster may be weathered or stained along the line, but the shell is intact.

MODERATE — 1/32″ to 1/8″ wide

This is the category misclassified more often than any other. A moderate crack accepts a feeler gauge and, depending on orientation and length, may or may not have penetrated past the plaster into the shell. The question is not “does it look concerning” — the question is “is it moving, and is it leaking.” Some moderate cracks stop growing after the first season. Others widen 1/32″ per year for three years and end up structural.

Our rule: document now, re-measure in 90 days, and make the repair decision on the second visit. The pool stays in service during that window unless a dye test shows active leakage.

STRUCTURAL — greater than 1/8″ wide

Anything over 1/8″ — the width of a nickel’s edge — has almost certainly penetrated the shell. Water is moving through it into the soil behind the pool, or soil water is moving through it into the pool, and the rebar network inside the gunite is at risk of corrosion. Schedule the repair within 30 days, before the next significant rain event saturates the soil and widens the crack further.

ACTIVE vs. STATIC

Width tells you severity; behavior tells you urgency. A static crack has stopped moving — measure it today, return in 6 months, the width is identical. A static 1/16″ crack is less worrying than an active 1/32″ crack, because the active one means something behind the shell is still shifting. The only way to tell them apart is documented re-measurement — the single thing most pool companies skip.

Crack Mapping — Why We Document Every Crack With Photos, Sketch, and Dates

Walk up to a crack with your eye and you see a line. Walk up with a feeler gauge set and you see a varying-width defect that might be 1/64″ at the top, 3/32″ at the middle, and 1/16″ at the bottom. Six months later without a written record of those numbers, you have no idea whether the crack has grown. Guessing on cracks is how small repairs turn into structural ones.

Primetime’s crack mapping protocol is four steps, applied to every crack — even the ones we suspect are purely cosmetic. Cheap documentation today is what makes a confident diagnosis possible in 90 days.

1. Full-crack photography. Wide shot showing crack location relative to tile, steps, light niches. Close shots at 4–6 inch intervals. Every photo is tagged with date and pool address in the file name.
2. Width log at 10+ points. We use a tapered feeler gauge set (0.002″ through 0.015″) and probe the crack at every 6 inches of length, plus at any visible width change. The measurements go onto a wall sketch with width numbers at each probed point. A 3-foot crack gets 7–10 measurement points; a 6-foot crack gets 12–16.
3. Sketch + reference measurements. The sketch includes distance from the waterline, distance from the nearest corner or step, and orientation. If we re-find this crack in 2 years, those references put our finger on it inside 30 seconds.
4. Dye test for active leakage. Pump off, release a dye pellet 6 inches from the crack. If dye streams into the crack, there is active water movement. If dye hangs in place and slowly disperses, the crack is not actively leaking today.

Every record goes into the homeowner’s file. When they call 18 months later with “I think it’s gotten bigger,” we open the file, drive out, and re-measure at the same probe points. Now we have data: the crack that was 1/32″ at Point 4 is now 3/64″. Roughly 0.016″ of movement over 18 months — slow but measurable. That data drives the repair scope.

The Three Repair Methods — Epoxy, Polyurethane, Staples

Once the crack is classified and mapped, the repair method follows from two variables: is the crack actively leaking, and is it structural. Those two questions generate a decision tree with three primary repair paths. We’ll walk each one, including the specific materials, pressures, and spacings we use on Dacula pools.

Epoxy Injection — The Default for Structural, Non-Leaking Cracks

Low-viscosity epoxy injection is our default for any structural crack (greater than 1/8″) that is not actively passing water. The product is a two-part structural epoxy with viscosity in the 300–500 centipoise range — thin enough to migrate through the full depth of the crack under moderate pressure, thick enough to cure into a load-bearing adhesive once the parts meet. Cured tensile strength exceeds the tensile strength of the gunite itself: once the epoxy cures, the crack is no longer a weakness.

We surface-seal the crack with a fast-cure epoxy paste, leaving injection ports at 6-inch intervals. The ports are short plastic nipples bonded over the crack. After the seal cures — typically 2 hours — we pump low-viscosity epoxy into the lowest port first, at 30–60 psi. As epoxy emerges from the next port up, we cap the lower port and move up. Port by port, the epoxy fills the entire profile from back of shell to front face of plaster.

After 24 hours of cure time, we remove the ports, grind the paste flush, and patch the plaster locally. For a pool under 5 years old with matching plaster still available, this patch can blend nearly invisibly. On an older pool with weathered or stained plaster, the patch will show as a lighter stripe — which is why structural repair on older pools is almost always followed by a full interior refinish.

Polyurethane Foam Injection — For Active Leaks First, Structural Repair Second

When a crack is actively passing water, epoxy alone will not hold. Epoxy is hydrophobic during its cure phase; it displaces away from water rather than bonding through it. Inject epoxy into an actively leaking crack and the product migrates to the driest path, leaves the wet path unsealed, and you’re back in 90 days with a repair that never stopped the leak.

The answer is a two-stage process. Stage one: hydrophilic polyurethane foam, injected at 6-inch port spacing at lower pressure (15–30 psi). The foam reacts with water in the crack, expands rapidly, and fills the void while water is still flowing. This stops the leak within minutes. By itself it is not a structural bond — polyurethane has perhaps 10% of the tensile strength of cured epoxy, and over time it will compress slightly.

Stage two follows 24–48 hours later, once the foam is stable and the surrounding substrate has dried. We drill through the cured foam at the same port locations and follow up with a standard epoxy injection, this time through a dry void. The epoxy now bonds structurally across the crack. Polyurethane stopped the water; epoxy restored the strength.

Stainless Staples (Helical Ties) — For Wide or Moving Cracks

Some cracks are too wide, too long, or too clearly active for injection alone. When we see a structural crack greater than 3/16″ wide, or one that has measurably grown between two documented visits, we add mechanical reinforcement: stainless steel staples, sometimes called helical ties in the concrete repair trade.

The staple is a helix-formed piece of 304 or 316 stainless rod, typically 1/4″ diameter and 10–14″ long depending on shell thickness. We drill pairs of angled holes straddling the crack at roughly 12-inch intervals and drive the staple in until fully seated. The helical profile bites into the gunite as it rotates — the staple is mechanically locked, not glued. Each staple crosses the crack and transfers tension across it, like rebar added after the fact.

Staples go in first, epoxy injection follows, and the section is then patched and re-plastered. On a pool wall that has shown real movement, this three-part sequence — staple, inject, re-plaster — is what keeps the crack from re-opening in a future freeze-thaw cycle. Dacula’s USDA Zone 8a climate brings roughly 20 freeze events per year, and each one applies small but repeated expansion-contraction stress to the shell. Without the staple, the repaired line can act as a stress concentrator and re-fail.

Interior Refinish — Why Structural Repair Almost Always Means Resurfacing

Here’s the part of the crack-repair conversation that surprises homeowners, and the part where we’re direct on the first call: if your pool is older than about 10 years and you need a structural crack repair, you will almost certainly want the interior refinished at the same time — not just the crack patched.

The reason is visual, not structural. Plaster weathers. It stains from iron, copper, and calcium. It etches from low-pH chemistry. After a decade, even a well-maintained plaster surface has a tonal signature — a specific gray-blue-white the eye reads as uniform from 20 feet. New plaster troweled onto a repair patch will not match. It will be brighter, whiter, flatter. From 20 feet the patch reads as a light stripe across the wall.

Three options, and we walk homeowners through all of them:

• Patch only. Cheapest, fastest, and the patch is obvious. Acceptable if the pool is already scheduled for resurfacing in 2–3 years, or the homeowner doesn’t care about cosmetic uniformity.
• Patch + single-wall refinish. Patch, then skim-coat and re-apply a single full wall. Softens the tonal transition at roughly 30% of a full refinish cost. Works on some pools, looks mismatched on others depending on how stained the rest of the interior is.
• Full interior refinish. Drain, chip out existing plaster, install bond coat, trowel new plaster across the full interior, acid wash, refill. The structural repair becomes invisible because there is no old plaster to contrast against.

For a standard 14,000-gallon Dacula backyard pool, a full interior refinish using mid-tier quartz-aggregate plaster runs $4,200 to $8,600 depending on surface prep and any tile or coping work bundled in. A premium pebble finish pushes toward the top of that range or slightly above. When the crack repair is already $1,500 to $4,000, the marginal cost of rolling into a full refinish is often less than it looks on paper — and it resets the surface life of the pool for another 10–15 years.

Bundling saves labor days. Drain and chip-out for a patch-only repair takes 1 day. Drain and chip-out for a full refinish takes 1 day — same day. If the pool is already empty and the walls are exposed for staple and injection work, adding the refinish extends the timeline by about 4 days, not doubles it.

When to Call Us and What to Send in the First Message

Dacula homeowners discover a pool crack one of three ways: they see it directly while skimming or cleaning; they notice their water level is dropping faster than evaporation alone would explain; or a leak detection company they called for an unrelated reason finds it. In all three cases, the fastest way to get a useful answer is to send the right information in the first text.

What we want in the first contact:

• Photos of the crack from three distances — wide shot of the pool showing the crack location relative to tile and steps, mid-range showing about 3 feet of wall on each side of the crack, and a close-up with a coin or ruler next to the crack for scale.
• Age of the pool and when you first noticed the crack. “1998 build, first saw the crack in March 2025” gives us more than “it’s old and I just noticed.”
• Water-loss rate if you have it. Inches per week is fine — a bucket test result is better. Anything above 1/4″ per day beyond normal evaporation is diagnostic.
• Neighborhood. Hamilton Mill, Sycamore Ridge, Ivey Chase, Providence Club, Chandler Ridge, Auburn Park, or an address off Winder Hwy, Hog Mountain Rd, or Dacula Rd — all of this helps us route scheduling and anticipate soil and slope conditions.

With that information we can give a directional answer before we drive out. “Likely hairline, cosmetic, let’s schedule an inspection in the next 2 weeks.” Or: “That width in that location is structural — we need eyes on it in the next 7 days.” The answer dictates whether we treat it as a scheduling inquiry or an active-repair priority.

One note we give every Dacula homeowner: do not DIY-patch a crack you haven’t measured. Pool-store epoxy kits cover almost any crack cosmetically, which means they also cover the evidence that lets us classify it later. We’ve been called to pools where a homeowner’s summer patch hid an active 1/8″ crack for 18 months, during which water migrated into the surrounding soil, eroded the bedding, and made the eventual repair both bigger and more expensive. If you suspect a crack: photograph it, measure it if you have a feeler gauge, and leave it alone until it’s documented.