Basalt Restorationin Big Island, HI

Basalt is the island's own stone, and it is everywhere a house meets the ground: entry steps and treads, pool and spa coping, pillars, garden and retaining walls. New, it is almost black. A few years of Hawaiian weather later it is grey, patchy and chalky, and the whole property looks tired.

There is a reason for that, and it is chemistry rather than dirt. Basalt weathers faster than most stone: rain and air break down its dark minerals into pale clays, a process geologists call clay mineral alteration. Moisture moving through the porous rock carries salts to the surface, where they dry into a white crust, which is efflorescence. Volcanic gases and acid rain strip the iron and magnesium out of the surface altogether and leave it looking bleached. None of that scrubs off, because the colour loss is in the stone.

Restoration puts the colour back. The surface is cleaned and the salt crust and soiling taken off, the stone is treated so its depth and true colour return, and the finish is sealed. Neighbouring surfaces, plants and pool tile are masked first, and the work is done in place, so nothing is lifted or replaced.

The difference is the whole character of an entry, a wall or a pool surround, for a fraction of the cost of new stone.