Black Limestone Cobble Setts 100x100 35-55mm

Please note that paving slabs are produced in batches and natural colour variations may occur. We strongly recommend ordering all required slabs in one order to ensure colour consistency. Mixing batches may result in visible shade differences.

Natural Sandstone & Limestone Paving Slabs – Ordering Guide

This guide applies to natural sandstone and limestone paving slabs supplied by Paving Central. It is designed to help homeowners order the correct quantity and understand the natural characteristics of stone before purchasing.

1. Understanding Natural Stone

Sandstone and limestone are natural products, and no two slabs are identical.

You should expect natural variation in:

Colour and tone

Texture and surface markings

Veining and fossils (especially limestone)

Size and thickness (within tolerance)

These characteristics are not defects — they are part of the appeal of genuine natural stone.

2. Calibrated Thickness – Important Information

All natural stone paving slabs are supplied as 22mm calibrated ( unless stated otherwise in product description 18mm or 20mm is also possible )

Calibration provides a thickness guide only. Due to the nature of natural stone, minor tolerances in thickness, size and edge finish should be expected.

This is normal and should be allowed for during installation.

3. How Much Should I Order?

Coverage figures shown on product pages are calculated allowing for joint widths of approximately 10–15mm.

However, additional material is always required.

Recommended Allowance

10–15% extra for most installations

Up to 20% extra for:

Smaller areas

Installations with lots of cuts

Mixed size or random laying patterns

Complex layouts or obstacles

This allowance covers:

Cutting

Wastage

Pattern adjustment

Natural stone tolerances

4. Breakage Allowance (Very Important)

Due to the nature of natural stone and palletised transport, a breakage allowance of up to 10% should be expected.

We strongly recommend factoring this into your order quantity.
Breakages within this tolerance cannot be accepted as a claim.

5. Mixed Size Paving Packs

Mixed size paving slabs are supplied to create a random laying pattern.

Please note:

Individual slab quantities may vary per pack

Coverage is based on the overall mixed layout, not exact slab counts

This variation is intentional and part of traditional stone paving design

6. Colour Variation & Blending (Very Important)

Natural stone varies in colour and tone.

To achieve the best finish:

Always mix slabs from multiple packs during installation

Do not lay from a single pack at a time

Dry lay and blend slabs before final fixing

This ensures an even distribution of natural colour variation and avoids patching.

7. Joint Widths & Coverage

Recommended joint width: approximately 10–15mm

Narrower joints may be difficult due to natural stone tolerances

Joint width will affect final coverage

Always allow additional material if tighter joint widths are planned.

8. Sealing Guidance

Natural stone is porous.

Sealing Recommendation:

Seal 3–6 months after installation

This allows the paving to settle, cure and naturally weather

Always seek professional advice on suitable sealers and timing

Sealing helps protect against:

Staining

Moisture ingress

Algae and organic growth

9. Checking Your Delivery

On delivery, we recommend:

Inspecting slabs before installation

Checking for transit damage

Ensuring quantities are correct

If there are any issues, notify us before installation begins.

⚠️ Installed stone is non-returnable.

10. Returns & Suitability

Natural stone is non-uniform

Colour variation, texture and calibration tolerances are not valid reasons for return

Once stone has been installed, it cannot be returned

If you are unsure about suitability, we strongly recommend contacting Paving Central for advice before ordering.

Need Help Ordering?

If you’re unsure how much stone you need or which product is right for your project, our team at Paving Central is happy to help before you place your order.

Natural Sandstone & Limestone Paving Slabs – Installation Guide

This installation guide applies to natural sandstone and limestone paving slabs supplied by Paving Central. It is written for homeowners while following best-practice installation methods to ensure long-term performance.

For best results, installation should be carried out by a competent installer.

1. Ground Preparation

Correct preparation is essential to prevent movement, cracking and long-term failure.

Excavate to allow for:

Sub-base

Bedding mortar

Paving slab thickness

Install a well-compacted MOT Type 1 sub-base

Compact in layers to achieve a solid foundation

Ensure the base is stable and level

Falls & Drainage

A minimum fall of 1:60 should be formed

The fall must slope away from buildings

This allows effective surface water drainage and prevents pooling

2. Bedding Method (Very Important)

All natural sandstone and limestone paving slabs must be laid on a full contact mortar bed.

✔ Correct Method

Lay slabs onto a full mortar bed

Apply a slurry primer to the back of each slab

Primer must be applied corner to corner, covering the entire underside

Ensure full contact between slab, primer and mortar bed

This method maximises adhesion, prevents voids and significantly reduces the risk of cracking or movement.

❌ Do Not Use

Spot bedding

Dot & dab methods

These methods are not suitable for natural stone paving.

3. Mortar Bed Guidance

Use a suitable full mortar bed designed for external paving

Mortar should be fresh and workable at the time of laying

Do not lay slabs onto dry, part-cured or uneven mortar

(Specific mix ratios are not specified to allow installer discretion and site conditions.)

4. Laying the Slabs

Lay slabs gently onto the prepared mortar bed

Tap down evenly using a rubber mallet

Check levels regularly with a spirit level

Maintain consistent joint widths

Clean excess mortar from the surface before it cures

Joint Widths

Recommended joint width: approximately 10–15mm

This allows for natural stone size and thickness variation

5. Coverage, Wastage & Breakages

Coverage figures are calculated allowing for approximately 10mm joints.

Always allow extra material for:

Cutting

Wastage

Pattern adjustment

Transit damage

Breakage Allowance

Due to the nature of natural stone and palletised transport, a breakage allowance of up to 10% should be expected.

We strongly recommend ordering additional material to cover breakage, cuts and wastage.
Breakages within this tolerance cannot be accepted as a claim.

6. Pointing & Jointing

Once the paving slabs are securely laid and the bedding mortar has cured:

You may use:

Traditional sand and cement pointing, or

A suitable external brush-in jointing compound designed for natural stone

Always follow the jointing product manufacturer’s instructions.

7. Sealing (Strongly Recommended)

Natural sandstone and limestone are porous materials.

We recommend:

Seal 3-6 months after the paving has been laid to allow time for the materials to settle . ( seek proffessional advise if you are unsure )

Sealing helps protect against:

Staining

Moisture ingress

Algae and organic growth

Colour fading

⚠️ Sealing is especially important for limestone, particularly darker colours.

8. Weather Conditions

Do not install paving:

During frost or freezing temperatures

In heavy rain

On saturated ground

Allow adequate curing time before:

Walking on the paving

Placing furniture

Allowing vehicle access

9. Vehicle Use

Natural stone paving slabs are suitable for light vehicle use only, when installed on a suitable sub-base and constructed correctly.

Incorrect installation may result in movement or damage.

10. Important Natural Stone Information

Natural stone will vary in colour, texture, veining and thickness

Supplied as calibrated thickness, which is a guide only

Minor tolerances are inherent and not considered defects