Natural vs Calibrated Indian Sandstone: Which Is Better?

October 28, 2026|Aarti Jain

A few millimetres of thickness can make the difference between a sharp sandstone patio and an uneven one. Buyers often overlook this detail, and it is the main difference between natural Indian sandstone paving and calibrated stone. Thickness affects how quickly slabs go down, how much skill the job needs, and how flat the finished surface feels underfoot. This guide covers both types with real thickness figures, laying steps and a simple buying checklist, so you can choose the right slabs before you spend.

Calibrated stone suits most homeowners and DIY projects. Every slab has the same thickness, so laying is faster and the surface comes out flatter. Natural, uncalibrated stone suits rustic gardens and experienced installers who are happy to adjust the mortar bed slab by slab. Both are real sandstone, and both last for years when laid on a full mortar bed.

What Is the Difference Between Natural and Calibrated Indian Sandstone?

The only real difference is thickness control. Both types come from the same quarries and are the same kind of stone. Natural slabs are split and left as-is, so thickness varies from slab to slab. Calibrated slabs are machined to a set thickness with a small tolerance. Stonewise lists a tolerance of ±2 mm on its calibrated products.

When you browse the full range of Indian sandstone paving, you will see thickness named in the product details and collections. Here is how the two types compare in practice:

Natural (uncalibrated): Thickness varies, the surface is riven, and laying needs more skill.
Calibrated: Thickness stays consistent, which means faster laying and more even joints. This is why calibrated sandstone paving is the usual choice for modern layouts.

What Is Natural Indian Sandstone Paving?

Natural Indian sandstone paving is sandstone split along its natural layers and sawn to size but not machined to a single exact thickness. The riven surface has a textured, hand-split feel. It gives good grip underfoot and a rustic character that suits cottage gardens and period homes.

Why people choose it:

It has an authentic look, with natural ripples and colour variation.
It suits informal or random layouts, where small height differences blend in.
It often costs less per square metre.

The trade-off is installation. Because slabs vary in thickness, a fitter must adjust the mortar depth under each one. Thicker slabs sit deeper, and thinner ones need more mortar. Done carefully, the result is excellent. If you rush, you get lipped edges and trip hazards.

What Is Calibrated Indian Sandstone?

Calibrated Indian sandstone is natural stone that has been cut or ground so every slab sits within a narrow thickness range. It is still real stone, with the same colour variation and texture. Only the thickness is controlled.

The Kandla grey-riven sandstone mixed patio paving slabs are a good example. The 30mm calibrated pack combines 600x900, 600x600, 600x290 and 290x290 slabs, so you get a varied pattern without uneven levels.

The main benefits are:

Faster laying, because each slab needs a similar mortar depth.
Tighter and cleaner joints.
Better results with large formats such as 600x900.
An easier job for first-time DIY builders.

Calibrated Indian sandstone paving comes in several thicknesses. Stonewise offers an 18mm calibrated budget range, 20mm smooth slabs, 22mm calibrated paving and the 30mm mixed patio pack.

How to Tell If a Sandstone Slab Is Calibrated

Many buyers are unsure what they are actually ordering. Use this short checklist before you pay:

Read the specification: A calibrated product states its thickness and tolerance, such as "22mm Calibrated" or "30mm Calibrated, plus or minus 2mm".
Look for a fixed thickness: Listings for uncalibrated stone often give only a rough range or no firm figure.
Measure your sample: Use a tape measure to check several edges of a sample slab. Calibrated slabs should read almost the same everywhere.
Ask before you order: If the thickness is not clear, ask the supplier to confirm it in writing.

Natural vs Calibrated Sandstone: Quick Comparison Table

Feature	Natural Indian sandstone paving	Calibrated sandstone paving
Thickness	Varies from slab to slab	Consistent, within a set tolerance
Surface	Riven or sawn	Riven, sawn or smooth honed
Laying speed	Slower	Faster
Skill needed	Higher	Lower
Best for	Rustic and informal gardens	Modern patios and DIY projects

Which Is Better for a Patio?

For most patios, calibrated stone is the better choice because it gives a flatter finish with less risk. Choose natural stone when a rustic look matters more than speed and you have an experienced installer.

The Raj Green smooth sandstone 600x600 sawn-edged paving slabs show how clean calibrated stone can look. They have a honed surface and a 20mm calibrated thickness, and they suit patios, walkways and garden areas.

Choose calibrated sandstone paving if:

You are laying the patio yourself.
You want a modern look with straight lines and tight joints.
You plan to use large sandstone paving slabs, such as 600x900.

Choose natural Indian sandstone paving if:

You want a hand-split, rustic look.
A professional will lay it.
Your design uses a random pattern.

How Much Does Indian Sandstone Paving Cost?

As of this writing, Stonewise prices Indian sandstone paving from £18.50 per m², including VAT. Natural Indian sandstone paving is often the cheapest per square metre, but allow for extra labour if your fitter needs more time to level each slab. Calibrated Indian sandstone paving in larger sizes and premium colours costs more, while budget calibrated ranges keep the price down.

Price per m² is only part of the cost. Add mortar, sub-base material, jointing compound and labour time before you compare options.

Plan your order carefully:

Order 10 to 15% extra for cuts, waste and breakages.
Check pack coverage. The Kandla Grey 30mm mixed pack covers 15.30 m².
Colour varies from slab to slab, so order a free sample before you buy a full pack.
Check delivery access. Delivery needs a hard, flat surface such as tarmac or concrete.

How to Lay Sandstone Paving Slabs

Lay slabs on a full mortar bed over a compacted sub-base. This works for both types. The steps below follow the guidance on the Stonewise product pages:

Excavate and plan for drainage: A 100 to 150mm layer of crushed hardcore is generally enough for foot traffic.
Compact the sub-base with a plate compactor.
Spread a wet mortar bed of 35 to 50mm, mixed at 4 parts washed sharp sand to 1 part cement.
Place each slab on a full bed. Never spot bed, because it causes instability. Tap it down with a rubber mallet.
Wait 48 hours, then fill the joints with a jointing compound.

With natural Indian sandstone paving, sort slabs by thickness before you start and lay similar ones together. With calibrated stone, keep one mortar depth across the whole area and check levels as you go. Clean cement stains straight away, and avoid acid-based cleaners. These are general guidelines, so follow your installer's advice and see Paving Expert for more detail.

Common Mistakes to Avoid

Most sandstone patio problems come from a few avoidable errors during ordering and laying. Watch out for these:

Mixing calibrated and uncalibrated slabs in one area, because the mortar depths will not match.
Spot bedding slabs instead of using a full bed.
Ordering the exact area with no allowance for cuts and damage.
Skipping samples and discovering colour variation after the pallet arrives.
Laying straight from one pack without mixing slabs for an even colour spread.

Avoiding these five mistakes costs nothing and protects both your budget and the finished look of your patio.

How to Clean and Protect Sandstone Paving

Indian sandstone paving needs very little upkeep, and both types need the same care. Sweep regularly, treat green algae and moss early, and use cleaners made for natural stone.

Pressure washing can bring back faded slabs, but technique matters. Use a fan nozzle and keep the lance moving to avoid damaging the surface. Our guide on pressure washing sandstone paving explains the method step by step.

A sealer adds protection after cleaning. EASYSeal Sandstone Sealer and Enhancer protects the surface and brings out the stone's colour.

Final Thoughts

Natural and calibrated stone are both real Indian sandstone, so the choice comes down to thickness, skill and style. Natural Indian sandstone paving gives a rustic, hand-split look and often costs less, but it needs a skilled fitter. Calibrated Indian sandstone paving lays faster, finishes flatter and suits DIY projects and modern designs.

Whichever you pick, check the thickness in the specification, order 10 to 15% extra, lay on a full mortar bed and never mix thicknesses in one area. Ask for samples first, so you can see the real colour and thickness before you commit.