Shellstone pavers or poured shell concrete for a Florida pool deck

If you want a shell surface around a Florida pool, there are two ways to get one. Shellstone pavers are a natural shell limestone, quarried, cut into pieces and laid with joints between them. A poured shell surface is concrete with crushed shell in it, cast in place and divided by a handful of control joints. Both read as coastal. They differ in grip, in joints, in upkeep and in how each is repaired, and that is what this guide compares.

We pour the second kind, Shellcrete by SRQ Modern, so read this knowing which side we stand on. Shellstone is a good material, and there are decks where it is the better choice. Those are below too.

What are shellstone pavers?

Shellstone is a sedimentary limestone made largely of fossil shell fragments that nature cemented together long ago. It is quarried in blocks and sawn into pavers, tiles, bullnose coping and step treads, usually sold with a tumbled or brushed face that softens the edges and opens the texture.

Because it is a stone and not a mix, every piece is different. Shell content, colour and the size of the holes vary from piece to piece and from one quarry lot to the next. That variation is the appeal, and it is also the first thing to plan for, as the repair section explains. It is close kin to coquina, the shell rock in some of Florida's oldest buildings; tabby, coquina and shellcrete untangles the names.

How absorbent shellstone is depends on the quarry and the product. Some is open and porous, some is dense. Ask the supplier for the stone's absorption figure rather than taking "porous" or "non-porous" on trust, because that one number decides how much the stone will drink pool water, sunscreen and leaf stain.

How is a poured shell surface different?

A poured shell surface turns the idea inside out. Instead of shell that nature bound into rock, it is shell bound into concrete on site. Ours is a blend of crushed seashells, fine sand and white Portland cement, mixed on site by our own crews and poured over a sound existing slab or as a new deck. Decorative shell is seeded into the surface before finishing.

What happens next decides the look. The surface can be opened up so the shell stands proud, honed flat to a soft matte, or polished under a roof. Because it is custom every time, the base colour, the shell blend and how far it is exposed are chosen per job, not picked from a pallet.

Instead of a joint around every piece, a poured deck has control joints set out before the pour, so any movement happens on a line somebody chose. It is one continuous surface between those lines.

Which grips better when wet?

Both can grip well, and both can be finished badly. On shellstone the grip comes from the natural texture and from the face it is sold with. A tumbled or brushed paver keeps its tooth; a honed or polished one has less of it, and polished stone at the water's edge is a slip question.

On a poured shell surface the grip comes from how far the surface is opened up. The exposed-shell finish has the most texture of the three, which is why it goes on coping, steps and anywhere a wet foot lands first. A honed deck is flatter and still broken up by the shell; we do not put a high polish where people climb out of the pool.

On either one, the sealer can undo the texture. A glossy film sealer turns a textured surface slick. A penetrating, matte sealer protects without filling the texture, so ask which one is going down before it does.

Paver joints or control joints?

This is the biggest practical difference. Shellstone pavers are laid one of two ways. Sand-set pavers sit on a compacted base with sand swept into the joints, and they behave like any paver deck: sand washes out, a corner settles, roots lift a section, and weeds and ants move into the gaps. Mortar-set pavers are bedded on a concrete slab with grouted joints, which stops the movement but means a crack in the slab can crack the grout, or the stone, above it.

A poured deck has no paver joints at all, only control joints. A hairline along one of those is the joint doing its job. The trade-off is that the surface can crack, and when it does the fix is a repair to a panel rather than a swap of one piece. The pavers comparison makes the same argument for a standard paver deck, and it holds for shellstone too.

Coping and steps: where pieces make sense

Shellstone is often bought for its bullnose coping, and that is a fair reason. The edge of a pool is where a pieced material does well: the pieces can be shaped off site and set on the bond beam with a clean line over the waterline tile.

A poured shell deck does not have to give that up. On one of our pool decks, the coping was cast off site as precast pieces and set on the pool shell, so the corners could be mitred and the top face set dense with whole shells for grip. The deck behind it was poured and divided by control joints. Pieces at the edge and one surface behind it is a combination worth asking for, whatever material you choose.

Which one stays cooler underfoot?

How hot a surface gets in Florida sun is mostly a question of colour: pale surfaces reflect more light and store less heat. Shellstone is sold in pale creams and whites, and a poured shell surface is pale by nature. Between the two, heat is close to a wash. Decide on grip, joints and upkeep, and choose the palest version of whichever you pick.

What does each need to keep looking right?

Shellstone is a limestone, which means it is calcium carbonate, and acid dissolves it. Acidic pool chemicals splashed on the deck, an acid wash or a strong cleaner can etch the face, the same chemistry the travertine comparison goes through in detail. Clean with a pH-neutral cleaner and low pressure. Whether it needs sealing, and how often, depends on how absorbent the particular stone is, which is another reason to get that figure from the supplier.

A poured shell surface needs a penetrating, breathable sealer, and it needs to be resealed as the surface asks for it. Never acid-wash it either: acid attacks the shell faster than the cement holding it, and the texture changes for good. Neither surface looks after itself. Both reward a hose, a stiff broom and getting to leaf stains before a wet week sets them.

How is each one repaired?

Here shellstone has a real advantage. A cracked or stained paver can be lifted and replaced on its own. The catch is matching it: natural stone varies from lot to lot, so a new piece bought later may not sit quietly beside the old ones. If you choose shellstone, keep a few spare pieces from the original order in the garage.

A poured surface is repaired by the panel, not by the piece. A crack that stays on a control joint is expected. A crack that wanders across a panel, or one that keeps moving, is usually the slab underneath telling you something, and that has to be dealt with before the surface is.

Can either go over my existing pool deck?

Often, but not the same way. Shellstone set over an existing slab goes down on a mortar bed, so the deck rises by the thickness of the stone plus the bed. That added height can fight the door thresholds, the coping and the fall of the deck toward its drains. Sand-set shellstone usually means taking the old slab out first.

A poured shell topping bonds to the slab you already have, which is why resurfacing an older deck is often a smaller job than replacing it. The word that matters is sound. A slab that is cracking structurally, or moving because the ground under it is moving, has to be fixed first, because a topping follows whatever is beneath it.

Shellstone pavers or poured shell: how to choose

Choose shellstone pavers if you want a natural stone with real geological variation, pieces you can replace one at a time, or you are building on bare ground and the added height is not a problem.

Choose a poured shell surface if you are working over a sound existing deck, you would rather have a few control joints than a joint around every piece, or you want the finish to change by area, exposed shell on the coping and steps and honed where the loungers go, from one mix.

If the second sounds like your deck, the pool decks page shows how we build one. Then send us photos of your deck for a quote, or call (941) 253-0400. We will look at the slab before we talk about the surface, and if shellstone is the better fit for your pool, we will tell you.