The weight of stone

The baths at Sassalda are not built on the rock. They are cut into it. The valley floor at 1,250 metres is a single bed of hard stone, and the four pools were made by removing it rather than by pouring anything in its place.

Why cut stone

Stone this dense holds heat. After the Spring Pool is drained each evening for cleaning, the walls around it stay at 31°C for another four hours. Guests who arrive for the first session at 07:00 step into a room that has never gone cold.

It also carries almost no sound. A wall of solid rock 60 centimetres thick stops traffic, wind and voices from the terrace above. That is most of the reason the pool halls measure NC-15 without any acoustic panels at all.

What it costs

Cutting is slow. The main hall took eleven months, and every wall shows the marks of the saw. We left them. Polished stone is slippery when wet, and the marks give your feet something to hold.