Custom Pools in North County
Why Nearly Every Pool Is Gunite
If you search "types of inground pools," you get a tidy three-way comparison - gunite, fiberglass, vinyl liner - presented as equal options at different price points. Then you start collecting plans for a pool in Carlsbad, Encinitas, or Rancho Santa Fe, and almost everything put in front of you is gunite. Homeowners ask us about this frequently, usually some version of: am I being steered?You're not. That comparison is written for a national audience. Two of the three options are shaped by conditions that don't hold along this coast, including our soils, and our lot geometry.
Our Soil is Not the Soil in the Brochure
A fiberglass shell is a catalog product: molded to a fixed shape, trucked to your property, set in a hole. A vinyl liner pool is a kit - wall panels, a footing, a liner. Both are built to a standard, then asked to survive whatever is underneath them. A gunite shell is the opposite: a reinforced concrete structure engineered to a specific set of soil values from a specific site.From Del Mar through Solana Beach and into Encinitas, much of what sits under the topsoil is the Del Mar Formation - an Eocene claystone interbedded with sandstone, roughly 200 feet thick at its type section near Del Mar, grading into the Santiago Formation around Encinitas and Carlsbad. The USGS description includes two words that should get a pool designer's attention: expansive and landslide-prone.
Expansive clay swells when it takes on water and shrinks when it dries. In a climate that delivers most of its rain in a few winter months and then goes dry for the remaining 8 months, that soil is in motion every year - and not uniformly. The shaded side of a pool near a slope holds moisture differently than the sun-exposed side 20 feet away.
Push a rigid molded shell into that and it has one response available: go along with it. Engineer a gunite shell for it and the geotechnical report drives the steel schedule, the shell thickness, the bond beam, and whether the structure gets tied to something more stable than the clay it sits in. Two pools of identical shape a mile apart can carry completely different reinforcing because the soils reports came back different.
Go inland to Rancho Santa Fe or the Vista hills and the problem inverts: we routinely hit decomposed granite and hard rock. Rock is a fine thing to found a pool on and an unforgiving thing to trim a fixed-shape shell into.
Fiberglass Shell Limitations
Fiberglass pools ship as one piece, and that single fact sets a hard ceiling on what they can be. Manufacturers top out around 16 feet wide and 41 feet long - the width cap isn't a design choice, it's the oversize load limit on the highway.California makes that concrete. Any load over 8 feet 6 inches wide runs warning signs on state highways, and loads over 10 feet wide face curfew restrictions in the San Diego metropolitan area. A 16-foot shell is a permitted, route-restricted, time-restricted move before it reaches your street.
Then it has to get from the street into the yard. On older coastal lots in Encinitas and Solana Beach, and on long tree-lined driveways in Rancho Santa Fe, the constraint is rarely the pool - it's the crane's reach and the width of the corridor. A shell that can't be flown over the house can't be installed at all.
Gunite arrives through a hose - pumped from the street, around the corner, through a side yard, and shot into the excavation. That's why it dominates on tight coastal lots, and why it's the only one of the three that gives you a genuinely custom shape: a raised spa on a shared wall, a beach entry, a vanishing edge oriented to one specific ocean view. The shell follows the design instead of the design following the catalog.
"Gunite" and "Shotcrete" Processes
Most people use the words as synonyms, but they're two different processes. Gunite is dry-mix. Dry material moves through the hose and the water is added at the nozzle by the operator. Shotcrete is wet-mix: ready-mixed concrete is pumped down the line and air is introduced at the nozzle.The consequence is where control of the water-to-cement ratio lives. Dry-mix typically runs 0.35–0.40, wet-mix 0.40–0.45 - but wet-mix is vulnerable to water added on site to keep it pumpable, which can push the ratio past 0.50. That costs compressive strength and, for a structure that holds water for 40 years, raises permeability. Dry-mix sets the ratio at the nozzle, which is why it demands a more skilled operator; it also throws more rebound, which has to be collected and never buried in the shell.
Done correctly, both reach the same place. The American Shotcrete Association recommends a minimum of 4,000 psi for pool shells so the reinforcing is properly encased. The question worth asking isn't "gunite or shotcrete" - it's what strength is specified and whether the nozzleman is certified.
Where Gunite Isn't the Answer
The case isn't one-sided. Gunite is a longer build with more site disruption. On a small lot with genuinely no equipment access, a fiberglass shell craned over the roof can be the only workable option. If speed governs, fiberglass wins on schedule. And near the lagoons - Batiquitos, San Elijo, Buena Vista, Agua Hedionda - a high water table introduces hydrostatic pressure that has to be managed with relief detailing regardless of shell type.Gunite dominates North County not because the alternatives are bad products, but because a coastline of expansive claystone, narrow access, custom geometry, and salt air removes most of the conditions under which they'd be the better choice.
Planning a yard that will include a pool? The shell is one decision inside a much larger set - grading, drainage, retaining, deck elevations, where the equipment lives. Those are landscape decisions, and far cheaper to get right on paper than in the field. Afuera Landscape Designs designs and builds under one roof. Contact us today.
