The material
What is Shellcrete?
Shellcrete is a decorative concrete surface made from crushed seashells, fine sand and white Portland cement, mixed and finished in place. It is used on pool decks, patios, driveways and walkways along the Florida coast because it stays cooler underfoot than dark paving, holds grip when wet, and can be laid straight over a sound existing slab.
How it is built up
On a resurfacing job the existing slab is cleaned and prepared, then the mix is placed as a topping of roughly one and a half to two inches. Control joints are saw-cut at about five-foot intervals so the surface cracks where it is told to rather than wherever it likes. The surface is then worked to the chosen finish and sealed.
The shell is the material, not a coating. That distinction matters: a spray-on texture sits on top of your slab and wears through, whereas this is a placed topping with the aggregate running through it.
On the name
Several Florida contractors use the word “shellcrete,” and the same broad idea also goes by tabby, coquina concrete, or washed-shell concrete. We are not going to pretend we invented shell in concrete — people have been doing it on this coast for centuries. What we control is the mix, the finishes, and the crews who place it.
What it costs
Shellcrete sits at the premium end of decorative concrete, because it is a placed, hand-finished surface rather than a coating and the finishing is skilled labour that cannot be sped up. The number moves with the condition of the existing slab, site access, the finish, and how much prep the deck needs before anything is placed — which is why every job is quoted after a site visit. A per-foot number given over the phone is a guess. Book a site visit.
Florida code and coastal exposure
Pool decks in Florida have to be non-absorbent with a slip-resistant finish, and sloped away from the water so it drains off rather than back in. Within roughly three thousand feet of saltwater, unsealed concrete also spalls faster as salt reaches the reinforcement. Both facts shape which finish is right for a given deck, and how often it should be resealed.
On site
The pour
Crushed seashell aggregate, fine sand and white Portland cement, mixed and placed on site. The shell is what gives it both the colour and the texture — there is no dye doing the work.
If the existing slab is structurally sound, Shellcrete is applied as a topping of roughly one and a half to two inches. Ours is a modern mix placed and finished to a specification we control.
The finishes
Common questions
What is Shellcrete made of?
Crushed seashell aggregate, fine sand and white Portland cement, mixed and placed on site. The shell is what gives it both the colour and the texture — there is no dye doing the work.
Is Shellcrete the same as tabby or coquina concrete?
They belong to the same family. Tabby is a historic Southeastern coastal concrete made with shell and lime, and coquina refers to the shell-limestone itself. Contractors across Florida use all of these names, sometimes interchangeably. Ours is a modern mix placed and finished to a specification we control.
Can it go over my existing concrete?
Usually, yes. If the existing slab is structurally sound, Shellcrete is applied as a topping of roughly one and a half to two inches. If the slab is heaving, badly cracked, or moving, it needs to be addressed first — a topping does not fix a failing base.
Does it get hot in the Florida sun?
It stays cooler underfoot than dark pavers or dark stamped concrete because the shell aggregate is light and reflects more sun. No exterior surface is cool in direct August sun, but this is one of the more comfortable options for a deck people cross barefoot.
Is it slippery when wet?
The honed and exposed-shell finishes keep texture at the surface, which is what gives grip. Florida rules for pool decks call for a non-absorbent, slip-resistant finish sloped away from the water, and the finish is chosen with that in mind.
How long does it last, and what is the warranty?
The standard workmanship warranty is one year, with extended options available at the time of quote. Longevity depends on sealing and on how much salt and sun the surface takes, which is why the maintenance schedule matters.
On film
The pour, and the finished decks
0:17Pouring a Shellcrete roof terrace on the Gulf
A Gulf-front house under construction: the terrace from the air, a bag of white cement and a bucket of shell going into the mixer, the crew screeding the topping flat, and the finished terrace from above.
Pouring shellcrete on a beachfront deck
0:14 · With sound
A Shellcrete pool deck and summer kitchen
0:16 · With sound
Shellcrete pavers on turf, on the water
0:15 · With sound
