Hydraulic tiles: lift, clean or leave alone

The cement tiles in old Barcelona flats are called hydraulic because they are not fired. Each one was made in a steel mould: a layer of coloured cement for the pattern, a backing of grey cement, pressed hard and left to cure in water. Between 1880 and 1930 the city’s workshops made them by the million, and most Eixample flats still have some. The colours come from mineral pigments, which is why they have faded so little in a century.

Owners who renovate face the same decision in every room: lift the tiles, clean them where they lie, or leave them alone. There is no single right answer, but there is an order in which to think about it.

Leave alone

If the floor is flat, the tiles are sound and the pattern is complete, leave it. A wash with neutral soap and a coat of wax is enough. Most of the patina that owners want to remove is wear, and wear is what makes an old floor look like one.

Knock on a few tiles with your knuckle. A dull sound means the tile is bonded to the bed below; a hollow one means it has come loose. A few loose tiles in a room are normal and can be lifted and reset one at a time. Fine cracks across a tile are not a reason to lift it either. They are usually old, and they show that the floor has settled, not that it is moving.

Clean

Where the tiles are stained or dull, they can be cleaned and polished in place. A good restorer grinds the surface by a fraction of a millimetre, enough to bring back the colour, and then seals it. The work takes two or three days a room, and the floor can be walked on the next morning. Ask to see a floor the restorer finished at least a year ago, so you can judge how the seal has worn.

Never let anyone use acid on a hydraulic floor. It eats the cement and leaves the colours flat, and there is no way back.

Lift

Tiles have to come up when the floor below them needs work: new pipes, underfloor heating, a sagging beam. Lifting is slow and some tiles always break, usually around one in ten. Number every tile on the back before it comes up, store them flat, and order replacements from one of the workshops that still make tiles to the old patterns. We know two, one in Barcelona and one near Girona. New tiles will not match exactly, because fresh cement is brighter, so we put them where a bed or a sofa will stand.

In the top floor at Consell de Cent the floor was lifted to lay underfloor heating, then relaid in its original pattern. Where tiles had broken, the restorer used pieces from a corridor that was being turned into a wardrobe. Nobody notices the wardrobe. Everyone notices the living room.

One last point. The pattern on these floors was designed for the room: a border along the walls and a carpet in the middle. If you move a wall, the carpet no longer fits. Plan the walls around the floor, not the other way round.