Cave Dwellings And The Rock That Allows Them

Houses cut into rock appear in widely separated regions and almost nowhere in between. The distribution follows geology precisely, because only certain stone permits it.

The rock has to be in a narrow range

Excavated dwellings require material soft enough to cut with hand tools yet strong enough to hold a ceiling without support.

Volcanic ash deposits are the classic case, along with certain soft limestones and consolidated sands, all of which cut readily and harden on exposure to air.

Where the stone is harder, the labour becomes prohibitive, and where it is softer, the roof will not hold, which is why the practice is geographically patchy.

Why anyone would dig instead of build

Excavation removes the need for building material, which matters most in regions with little timber and no easy source of usable stone.

The spoil is often usable too, cut into blocks for the front wall and outbuildings, so the excavation supplies the construction that completes it.

Extension is straightforward. Adding a room means digging further in, which requires no new material and no structural connection to what exists.

The temperature argument

Rock a few metres in stays close to the local average temperature year-round, so the interior is cool in summer heat and mild in winter cold.

In regions with extreme seasonal swings that stability is a substantial advantage, and it is achieved without fuel, insulation or any moving part.

The same property made these spaces valuable for storage, and many are used for keeping food, wine and produce long after people stopped living in them.

The problems that come with it

Ventilation and light are the main difficulties, and traditional layouts address both by keeping rooms shallow and putting all openings in the excavated face.

Moisture is the other issue, since rock surfaces can be damp and there is no through draught, and traditions developed specific ways of handling it.

Structural risk is real where the rock weathers, and collapses of a facing or a ceiling are the reason many such settlements were evacuated in the last century.

Status and the recent reversal

These dwellings were widely regarded as housing of last resort, and clearance programmes moved residents into conventional buildings, sometimes against their wishes.

The judgement has partly reversed, with the thermal performance now regarded as an advantage and the dwellings restored and occupied deliberately.

That reversal is uneven. Where the rock is still deteriorating the original safety concern remains, and the value of the form does not remove the reason it was abandoned.