Stone Cladding

Four stone families dominate Iranian facades. Travertine, with its natural porosity and cream to walnut tones, is the most widely used, quarried notably at Mahallat, Azarshahr and Takab. Marble is denser and takes a higher polish. Granite is the hardest option, absorbing under half a per cent of water, and is the best choice for entrance floors, stair treads and skirtings subject to wear. Chini stone is bright and economical but less durable in freeze-thaw conditions.

Facade slabs are normally 20 to 30 mm thick, rising to 40 mm for large panels or installation at height. A 25 mm slab weighs roughly 60 to 70 kg per square metre, and that weight is precisely why the fixing method matters. Wet fixing with mortar is acceptable only at low level and with stainless anchor pins. Higher up, dry fixing on a galvanised angle and tee subframe with stainless bolts is mandatory. Stone held to a wall by mortar alone eventually detaches under freeze-thaw cycling and becomes a life-safety hazard.

Common errors include using plain black, ungalvanised anchor pins, which rust, stain the facade brown and eventually fail. The second is ignoring the direction of the stone's bedding; wrongly oriented veining creates a path for water and cracking. The third is fully packing mortar behind dry-fixed stone, which traps water and destroys the ventilated cavity.

For porous stones such as travertine, a penetrating water-repellent treatment reduces staining and efflorescence, but it must not form a glossy sealed film, which would stop the stone breathing.