Natural Stone Cladding — Granite, Sandstone, Marble

What it is

Dimension stone — granite, sandstone, limestone, marble or slate — cut into slabs and hung on a facade with stainless steel anchors in a drained, ventilated cavity.

Indian projects have exceptional access to domestic granite and sandstone, which is why stone remains commercially viable here at scales that would be prohibitive elsewhere.

Specification at a glance

Property	Typical specification
Stone	Identified to IS 1123, named quarry and batch
Thickness	25mm — 40mm typical, by calculation
Finish	Honed, flamed, bush-hammered, polished
Anchors	Stainless steel, grade by exposure
Fixing	Kerf, undercut or dowel, into a drained cavity
Testing	Flexural, compressive, absorption, pull-out

The anchor is the design, not the stone

A stone facade fails at the anchor, not through the slab. Everything that matters structurally is in the fixing:

• Anchor grade. 304 stainless pits in coastal and heavily polluted air; 316 is the grade for those environments.
• Edge distance and kerf depth control whether the anchor pulls through the slab edge.
• Pull-out testing on the supplied stone is the only evidence the anchor capacity is real.
• Each slab independently supported, so a single failure is not progressive.

What drives the cost

Stone type and rarity · slab thickness · finish · panel size and yield from the block · anchor type, with undercut costing more than kerf · wastage, which is high for stone · testing programme · handling, weight and crane time.

Where projects go wrong

• Thickness copied from another project. Wind pressure and stone strength are both project-specific.
• Test values taken from quarry literature rather than the supplied batch.
• 304 stainless near the coast. It stains and pits within a few seasons.
• Wet fixing above low rise. Mortar adhesion is not a facade support system.
• No breakage allowance. Stone chips and cracks in transit; the order must carry margin.

Standards referenced

Stone identification under IS 1123. Compressive strength testing to ASTM C170. Wind loading on cladding and anchors under IS 875 (Part 3).