Sunken or freestanding hot tub: looks, access, cost and pitfalls

A sunken hot tub looks wonderful in photographs. Water level with the terrace, a line of stone or decking running straight to the edge, nothing to climb. It is also the installation we get asked to fix most often when someone else did it badly. This guide sets out what you gain, what you give up, what it costs on top of the tub, and the middle option that suits most Mallorcan terraces.

How the two look

A freestanding tub sits on its base with the cabinet showing. Modern cabinets are decent, but a 90 cm high box of grey panels is still a box, and on a small terrace it dominates. Most owners soften it with planting, a pergola or a built surround.

A fully sunken tub disappears. You see the acrylic rim and the water, framed by whatever surface you chose. It suits a flat terrace with a long view, a roof terrace in Palma, or a courtyard where the tub needs to feel like part of the architecture rather than an appliance. It is also the quietest option, with the pumps below ground level.

Step-in height

This is the most practical argument for sinking. A Serra 5 is 90 cm tall, a Mar 7 is 95 cm. Getting into one from ground level means a step or two and a swing of the leg over the rim. Fine when you are forty. Less fine when you are seventy, or carrying a drink, or when it is dark and the stone is wet.

A sunken tub lets you sit on the rim and swivel in. A partially sunken tub, which we come to below, gets you most of that benefit with a single 40 cm step.

Safety for children

Here the argument reverses. A freestanding tub with the cover locked is hard for a small child to reach. A sunken tub at floor level is a 90 cm deep pool with a soft lid on it. Cover locks matter more, so does a lifter that leaves the cover standing upright, and so does a lockable gate if the terrace opens onto a garden where children play. None of this rules out sinking the tub, but budget for it and take the cover discipline seriously.

Cover handling

A standard cover lifter clamps to the cabinet sides and pivots the cover up and back. With a fully sunken tub there is no cabinet above ground to clamp to. The options are a deck-mounted lifter, which needs 60–80 cm of clear space behind the tub, or an under-mount bracket fitted before the decking goes down. Either way, it must be planned before the surround is built, not after. A cover lifter is €345 in our price builder, and on a sunken install it is not optional.

Service access

Every hot tub has an equipment bay behind one cabinet panel: pumps, heater, control box. A technician needs to get a panel off and reach inside. On a freestanding tub that means walking round it. On a sunken tub it means a hatch.

The minimum that works is a removable section of decking or a stone-finished hatch at least 60×90 cm, directly in front of the equipment bay, with enough space inside the pit to kneel. Better still is a pit that is 50 cm wider than the tub on the service side, so someone can get down into it. Also plan for the other three sides: a jet or a union can leak anywhere, and if the pit is tight to the shell on three sides, a leak there means lifting the tub out with a crane.

The drainage pit

Water gets into the pit. Rain blows under the cover, bathers splash, the tub is drained twice a year. If that water has nowhere to go, the pit fills, the pumps sit in it and the cabinet rots. A pit needs either a gravity drain to a lower point, which is rare on a flat terrace, or a sump with a float-switch pump. Our drainage pump kit is €175. Fit it, and test it before the decking goes on.

What it costs

A sunken installation adds €2,900–4,500 to the price of the tub, plus the surround. The spread depends on what the ground is. Cutting a pit into a marès terrace in Santanyí is quick. Breaking through a reinforced concrete slab on a Son Vida roof terrace is not, and it may be structurally impossible, which is a question for an engineer before anyone picks up a tool.

On top of that, the surround:

• Composite decking €210–260 per m²
• Timber decking €180–230 per m²
• Natural stone €240–320 per m²

A typical surround of 15–20 m² around a Serra 5 lands at €3,200–5,200 in composite, or €3,600–6,400 in stone. So the realistic all-in premium for sinking a tub is €6,000–10,000 above the same tub standing on a slab.

What goes wrong

• No access. The commonest fault. Tiled right up to the rim, no hatch, and the first pump failure means breaking the terrace.
• Water pooling. No drain, no sump, and a pit full of green water by the second winter.
• Not level. A tub that is 2 cm out across its width overflows at one corner every time two people get in. Hard to correct once the surround is built.
• No ventilation. Pumps and heaters need air. A sealed pit cooks the electronics.
• The cover. No lifter planned, so the cover ends up dragged across the stone, and lasts two years instead of five.

The partially sunken compromise

Most of the tubs we sink go down 40–50 cm, not the full 90. The rim ends up at bench height, which is where you want it. You sit, swing round, and you are in. The cabinet still shows for 40–50 cm above the deck, so a standard cover lifter clamps on as usual, there is a panel to remove for service without a hatch, and the pit is shallow enough to drain easily or even to leave open on one side.

It also looks right. A rim at seat height reads as a built feature, not a hole in the floor, and it gives you somewhere to put a towel.

Decking heights

If you are building a raised deck anyway, think about it the other way round. Instead of digging the tub down, bring the floor up. A deck raised 40 cm around a freestanding tub produces exactly the same sitting-height rim as a partial sink, with no excavation, no sump, and service access from underneath the deck through a removable section. On a sloping finca plot this is often the cheapest route to the sunken look.

Whichever direction you go, keep the finished surface 20–30 mm below the acrylic rim. Flush looks tidy but means water runs onto the deck and under it.

Stone or composite around a sunken spa

Local stone, marès or a honed limestone, is the natural choice on an older property and it handles the sun well. The drawbacks are weight, which matters on a roof terrace, and slipperiness when wet unless the finish is textured. Hatches in stone are heavy and need a frame.

Composite decking is lighter, cooler underfoot than dark stone in July, and far easier to make into a removable hatch. It fades slightly in the first year and then settles. Timber is cheaper still and looks best on a finca, but it needs oiling every year here and it moves.

On a fully sunken tub, composite is the practical answer. On a partial sink or a raised deck, use whichever suits the house.

Resale

Buyers like a tub that looks built in, and a well-integrated spa terrace photographs well in a listing. But a sunken tub that has failed, or one with no access, is a liability a surveyor will flag. If you plan to sell within five years, the partial sink or raised deck gives you the look with the lowest risk of a problem you cannot get at.

Permits and the community

A freestanding tub on a private terrace normally needs no building licence in Mallorca. A sunken installation involves works, and may need a comunicación previa from your council. On a community terrace, or anywhere a slab is cut, speak to the community first. Check with your council and community before the pit is dug.

Where to go from here

Our terraces page shows the three approaches side by side with example costs, and the price builder lets you add a sunken installation, decking and a cover lifter to any model. Send us a photo of the terrace and tell us what it is built on, and we will say which option makes sense before anyone quotes.