Article: How to Lay Indian Sandstone Paving: A Complete Step-by-Step Guide
How to Lay Indian Sandstone Paving: A Complete Step-by-Step Guide
Laying Indian sandstone isn't complicated, but it's unforgiving if you skip steps or cut corners. A properly laid sandstone patio will last decades with almost no maintenance. A poorly laid one will start rocking within a year. This guide covers the full process from excavation to pointing — the same method professional landscapers use — so you can decide whether to tackle it yourself or hand it to a contractor knowing exactly what "done properly" looks like.
Before you start: what you'll need
Tools
Spade and shovel, wheelbarrow, spirit level (1200mm minimum), rubber mallet, string line and timber pegs, tape measure, wacker plate / hand tamper, cement mixer or mixing board, pointing trowel, soft brush, bucket and sponge, angle grinder with diamond blade (for cuts), knee pads
Materials
Indian sandstone paving slabs (area + 10% for cuts and wastage), MOT Type 1 sub-base aggregate, sharp sand, cement (OPC), paving primer / SBR bond bridge (recommended for sawn sandstone), jointing compound or kiln-dried sand, DPM membrane (optional, for clay soils)
How much stone do you need? Measure your area in square metres (length × width). Add 10% for cuts, wastage, and the odd slab you don't like the look of. Indian sandstone is a natural product — some variation between slabs is normal, and having spares means you can set aside any outliers without being short.
The step-by-step process
Plan your layout and set your levels
Mark out the patio area using string lines and timber pegs. Your finished paving surface must be at least 150mm below the damp-proof course (DPC) of your house — this is a building regulations requirement, not optional.
You also need a drainage fall away from the building. The standard is 1:60 — that's roughly 17mm of fall per metre. So a patio extending 3 metres from the house needs about 50mm of fall from the house wall to the far edge.
Run a taut string line at your finished paving level, including the fall, and use this as your reference throughout the build.
Excavate
Dig out the entire area to the required depth. You need room for: 100–150mm of compacted sub-base, 30–40mm of mortar bed, and the thickness of your paving (typically 22mm for calibrated Indian sandstone). That's a minimum dig depth of around 150–210mm below your finished level.
If you're working on clay soil, dig an extra 50mm deeper and lay a geotextile membrane before the sub-base to stop clay migrating up into the aggregate over time.
Lay and compact the sub-base
Spread MOT Type 1 crushed aggregate across the excavated area in layers of no more than 50mm at a time. Compact each layer with a wacker plate (or hand tamper for small areas). Build up to a total compacted depth of 100mm for a patio with foot traffic only — 150mm if the area might take occasional vehicle weight.
The sub-base should follow the same fall as your finished paving. Check with a spirit level and string line after compacting. This is the foundation of your entire patio — get it right and everything else is straightforward. Get it wrong and nothing will save it.
The #1 mistake that ruins DIY patios: spot bedding. Some guides suggest laying slabs on five spots of mortar — one in each corner and one in the middle. This is how patios fail. Within six months, individual slabs start rocking. Within a year, the pointing cracks. Within two years, the whole surface is unstable. Always lay on a full mortar bed. It takes more mortar and more time, but it's the only method that produces a patio that lasts.
Mix the mortar bed
Use a semi-dry mix of 5 parts sharp sand to 1 part cement. "Semi-dry" means the mix should hold together when you squeeze a handful, but shouldn't ooze water. If it's too wet, slabs can sink under their own weight and you risk mortar leaching through the stone (white staining on the surface that's very difficult to remove).
Spread the mortar across an area slightly larger than the slab you're about to lay, to a depth of roughly 30–40mm. You'll compress this when you bed the slab in.
Prime the slab (recommended)
For riven sandstone, priming is optional but beneficial. For sawn and honed sandstone, it's strongly recommended. A paving primer (SBR slurry or a proprietary product like Pro-Prime) is painted onto the back of each slab before laying. It creates a bond bridge between the stone and the mortar that massively improves adhesion.
To make SBR slurry: mix SBR bonding liquid with cement to a thick, paint-like consistency. Brush it generously across the entire back of the slab. Lay the slab while the slurry is still wet — it needs wet-to-wet contact with the mortar bed.
Lay the slabs
Lower each slab carefully onto the mortar bed — don't slide it, as this pushes mortar into the joint. Tap it into position with a rubber mallet, working from the centre outwards in a diagonal pattern. Check the level and fall with a spirit level after every slab.
Leave joints of 8–12mm between slabs. For riven sandstone with hand-dressed edges, joints will naturally be slightly wider and more irregular — this is part of the character. For sawn sandstone, you can achieve tighter, more uniform joints.
Keep a bucket of clean water and a sponge beside you at all times. If any mortar splashes onto the face of a slab, wipe it off immediately. Dried cement stains are extremely difficult to remove from natural stone and will leave permanent marks if left.
Open multiple packs. Indian sandstone has natural colour variation. If you work through one pack at a time, you can end up with one area noticeably lighter or darker than another. Instead, open three or four packs at once and draw slabs from all of them. This distributes the variation evenly and gives a much more natural-looking result.
Let it set
Don't walk on the paved area for at least 24–48 hours. The mortar bed needs time to harden and the slabs need to bond. If rain is forecast within 24 hours, cover the fresh paving with a tarpaulin to stop water disturbing the mortar before it cures.
Pointing (jointing)
This is the final and most visible step. There are two main methods:
Traditional sand and cement pointing: Mix 3 parts kiln-dried sand to 1 part cement into a semi-dry crumbly mix. Push the mix firmly into each joint with a pointing trowel, compacting it down. Smooth off flush with the slab surface. Brush away any excess with a soft brush. Do this in dry weather — rain on fresh pointing will wash the cement out and stain your slabs.
Brush-in jointing compound: Products like EASYJoint or ProJoint are swept into the joints and then activated with water. They're faster, less prone to staining, and more forgiving for DIYers. They also stay slightly flexible, which helps accommodate natural movement.
Whichever method you choose, this is where neatness matters. Bad pointing will ruin the look of even the best-laid patio.
Mortar mix ratios: a clear reference
You'll find different ratios quoted across different guides. Here's what to use and when:
| Purpose | Mix Ratio | Consistency |
|---|---|---|
| Sub-base concrete (if needed over clay) | 6:1 ballast to cement | Stiff, barely workable |
| Full mortar bed (laying) | 5:1 sharp sand to cement | Semi-dry — holds when squeezed, no water oozing |
| Bond bridge / primer | SBR + cement slurry | Thick paint consistency |
| Pointing (sand & cement) | 3:1 kiln-dried sand to cement | Crumbly, semi-dry — never sloppy |
Riven vs sawn: does the laying method change?
Riven sandstone
Riven slabs have a naturally textured surface and hand-dressed edges. They're more forgiving to lay because the uneven surface hides minor imperfections. However, riven slabs often have slight thickness variation (±2–3mm even when calibrated), so you'll need to adjust your mortar bed depth slab by slab. The semi-dry 5:1 mix accommodates this well — tap each slab to level with your rubber mallet.
A bond bridge is optional for riven sandstone but won't hurt. Joints can be 10–15mm wide to suit the hand-dressed edge character.
Browse Riven Indian Sandstone →
Sawn and honed sandstone
Sawn slabs have machine-cut, clean edges and a smooth surface. They look more contemporary but require more care during installation. The smooth back surface doesn't grip mortar as readily, so a bond bridge is strongly recommended. Handle them carefully — clean edges are more susceptible to chipping than riven edges. Use 8–10mm joints for a tight, uniform look.
Browse Sawn & Honed Indian Sandstone →
Common mistakes to avoid
1. Spot bedding
Already covered above, but it's worth repeating: always lay on a full mortar bed. Five spots of mortar is a shortcut that guarantees failure.
2. Wet mortar mix
Too-wet mortar causes two problems. First, slabs sink under their own weight, making levelling impossible. Second, moisture leaches through the stone and carries cement to the surface, leaving white staining (efflorescence) that's very hard to remove. Keep the mix semi-dry.
3. Not priming sawn sandstone
Sawn sandstone has a smooth back that doesn't bond to mortar as well as a riven surface. Without a primer, slabs can debond over time — especially in freeze-thaw cycles. It takes five minutes per slab and makes a real difference to long-term stability.
4. Pointing in the rain
Fresh sand-and-cement pointing dissolves in rain. The cement washes onto the slab face and leaves permanent staining. Check the weather forecast and only point when you have at least 24 hours of dry weather ahead.
5. Skipping the sub-base
Laying slabs directly onto soil or onto a thin layer of sand is not a proper installation. Without a compacted sub-base, the ground will settle unevenly, and your paving will move. There are no shortcuts here — MOT Type 1, compacted properly, is non-negotiable.
6. Forgetting the fall
A flat patio collects puddles. 1:60 fall away from the house (17mm per metre) gives you reliable drainage without being noticeable underfoot. Without it, you'll have standing water after every rain.
Should you seal Indian sandstone?
Sealing is optional, not essential. Indian sandstone is naturally durable and will perform well outdoors for decades without sealant.
However, sealing can be worth considering if your patio is near a barbecue area (oil and grease stains), under trees that drop berries or sap, or in a high-traffic area where you want easier cleaning. A breathable impregnating sealer won't change the appearance of the stone but will make stains sit on the surface rather than soaking in, giving you time to wipe them away.
If you do seal, wait at least 4–6 weeks after laying to allow all moisture to fully evaporate from the mortar and stone before applying. Sealing over trapped moisture can cause discolouration.
How long does it take?
A rough guide for a typical 20m² patio:
| Stage | Time (approx) |
|---|---|
| Planning, measuring, marking out | Half a day |
| Excavation (by hand) | 1–2 days |
| Sub-base laying and compaction | Half a day |
| Laying slabs on full mortar bed | 2–3 days |
| Curing time (don't walk on it) | 1–2 days |
| Pointing | Half to full day |
A professional landscaper with a labourer will typically complete a 20m² patio in 3–5 days. If you're doing it yourself for the first time, expect a full week including the learning curve.
When to hire a professional
Laying Indian sandstone is achievable as a DIY project if you're patient and methodical. But there are situations where hiring a landscaper is the smarter choice: complex levels or multi-level patios, areas with significant slope or drainage challenges, patios larger than 30m², if you need to work near drains or utilities, or if the area is directly against the house and DPC compliance is critical.
A properly laid sandstone patio should last 25–30 years or more. The cost of professional installation (typically £80–120/m² including labour and materials, depending on location and complexity) is worth it if it means the job is done right the first time.
Ready to start your project?
Browse our full range of Indian sandstone — all calibrated to 22mm, stocked year-round at our Nottingham yard, and delivered free to mainland UK.
Browse Indian Sandstone Order SamplesRelated guides
Indian Sandstone Colours: A Complete Guide →
Indian Sandstone Paving — Full Range →
