Does Raj Green Indian Sandstone need sealing?

Yes, sealing is essential — not optional — for Raj Green sandstone installed outdoors in the UK. As a porous natural material, unsealed sandstone absorbs moisture and organic staining over time, and UK freeze-thaw cycles cause progressive damage to unsealed stone as absorbed moisture expands on freezing. An impregnating breathable sealer applied after installation prevents both problems. Apply before grouting to avoid grout haze staining the stone surface. Reseal every two to three years to maintain effective protection.

Is Raj Green sandstone slippery when wet?

No. The naturally riven surface texture of Raj Green sandstone provides inherent structural slip resistance built into the stone itself rather than applied as a surface coating. The textured face channels water away from underfoot contact points and maintains safe traction in wet conditions. This slip resistance does not reduce with age or wear — it is one of the key practical advantages of naturally riven stone over smooth or polished finish alternatives.

What does 20mm calibrated mean?

Calibrated means each slab has been machine-ground on the reverse to a precise and consistent thickness of 20mm. Unlike uncalibrated stone where individual slab thickness varies and each piece requires separate bedding adjustment, calibrated slabs sit flat on a consistent mortar bed, producing a level, professional finished surface more quickly and reliably. 20mm calibrated is the correct specification for domestic pedestrian patio and pathway installations.

How many slabs do I need for a 18.9 square metre patio?

This pack contains 35 slabs covering exactly 18.9 square metres at standard 10mm joint spacing. For a finished patio footprint requiring around 16 to 17 square metres of space, ordering this single pallet factors in the recommended 10 percent cutting and edge layout wastage allowance.

How does Raj Green sandstone perform through UK winters?

Properly installed and sealed Raj Green sandstone performs reliably through UK winter conditions including persistent frost, heavy rainfall and wet-dry cycles. The sealer prevents moisture penetrating the stone's pores, eliminating the freeze-thaw damage mechanism. A correctly prepared MOT Type 1 sub-base at adequate depth — 150mm minimum on stable ground, 200mm on heavy clay — provides foundation stability that prevents surface displacement from seasonal ground movement.

Can these slabs be used for a driveway?

These 20mm calibrated slabs are specified for pedestrian patio and pathway applications. Driveway use requires a minimum 40mm slab thickness and a reinforced sub-base specification designed for vehicle loading. See our driveway paving collection for correctly rated products and specifications.

What is the difference between Raj Green and Kandla Grey Indian sandstone?

Raj Green carries a warmer, earthier palette of green, brown, buff and grey tones with organic warmth that suits traditional, rural and heritage garden settings. Kandla Grey offers a cooler, more composed mid-grey tone with less tonal complexity, suited to contemporary and minimalist schemes where a neutral ground plane is preferred. Both are premium natural stone materials — the choice comes down to the design character and architectural context of your specific project.

What laying pattern works best for 900x600mm slabs?

The most widely used laying pattern for 900x600mm slabs is stretcher bond — rows offset by half a slab length in a running brick pattern. This is simple to set out, minimises cuts and produces a clean, structured result that suits both modern and traditional gardens. Stack bond with fully aligned joints is used in formal or minimalist designs. Always use a full mortar bed rather than spot bedding for slabs of this size. See our installation guide for complete step-by-step instructions.