Autumn Brown Sandstone for UK Patios

[edit] Introduction

Autumn Brown sandstone is a natural sandstone commonly used for external paving and landscaping. The term generally refers to a commercially available range of Indian sandstone characterised by combinations of brown, buff, grey and other earthy tones. As with other natural stone, colour, texture and mineral characteristics can vary between individual slabs and batches.

The suitability of Autumn Brown sandstone for a particular application depends on its physical and technical properties, including strength, water absorption, frost resistance, abrasion resistance and slip resistance. These properties should be assessed against the requirements of the proposed use rather than assumed from the stone's name or appearance.

[edit] Characteristics and appearance

Autumn Brown sandstone has a varied appearance, with individual slabs potentially containing different proportions of light and dark brown, buff and grey tones. Natural variation is an inherent characteristic of sandstone and means that individual slabs will not normally be identical.

A representative range or control sample is preferable to a single sample when specifying natural stone for a project, as it gives a better indication of the variation that may occur in the completed installation. The finish also affects the appearance and performance of the stone. Riven, sawn, honed, sandblasted and other finishes can produce different textures and surface characteristics.

The term 'Autumn Blend' may also be used commercially for sandstone products with similar colour characteristics, but these trade descriptions should not be assumed to define an identical geological material. The precise characteristics of a product should be established from its technical documentation.

[edit] Applications

Autumn Brown sandstone can be used for patios, terraces, courtyards, paths and other external landscaping applications where its technical properties are appropriate. It may also be used for steps, walling, copings and other landscape features.

Sandstone can also be used for internal flooring and other applications, provided that the selected material and finish are suitable for the intended environment. Its porosity and susceptibility to staining should be considered when specifying it for internal or frequently wetted areas.

Use in driveways and other areas subject to vehicle loading requires particular care. The suitability of a particular sandstone depends on its tested mechanical properties, thickness, unit dimensions, bedding and the design of the supporting construction. A paving slab that is suitable for pedestrian use should not automatically be assumed to be suitable for vehicular traffic.

[edit] Selection and specification

The required dimensions and thickness should be selected according to the application and the characteristics of the particular stone. Common commercial formats include rectangular and square paving units, as well as mixed-size paving packs, but available dimensions vary between suppliers and products.

Technical documentation should be examined before specifying the material. Relevant test data may include water absorption, apparent density, flexural strength, compressive strength, resistance to abrasion and slip or skid resistance, depending on the intended application.

The finish should also be specified because surface texture can affect appearance, cleaning requirements and slip performance. Where slip resistance is important, the performance of the actual stone and finish should be established through appropriate testing rather than inferred solely from descriptions such as 'riven' or 'natural'.

[edit] Installation

Sandstone paving should be installed on a suitably designed and prepared supporting construction appropriate to the expected loads and ground conditions. This will generally include a properly compacted sub-base, suitable bedding and correctly formed falls and drainage.

The appropriate laying method depends on the paving units, substrate, loading and site conditions. Joints should be designed and formed in accordance with the paving system and the manufacturer's technical requirements. Excessive reliance on a particular joint width or bedding thickness should be avoided unless it has been established as suitable for the specified paving system.

Paving should generally be laid to falls so that water drains away from buildings and does not remain standing on the surface. Drainage design should take account of the surrounding ground, surface water management and the requirements applicable to the project.

Where slabs have significant natural colour variation, slabs from different packs should be mixed during installation to distribute the variation across the completed area rather than creating visibly different zones.

[edit] Maintenance

Sandstone is a porous material and can absorb water and contaminants. Regular sweeping and appropriate cleaning can help maintain its appearance and reduce the accumulation of organic matter such as moss and algae.

Cleaning products should be suitable for natural sandstone. Strongly acidic or otherwise aggressive cleaning agents can damage some stone surfaces and should not be used unless their suitability has been established. Pressure washing can also damage some finishes if excessive pressure or an inappropriate technique is used.

Sealing is not universally required. Where a sealer is specified, it should be selected for the particular stone, finish and intended application, and applied in accordance with the product manufacturer's instructions. The need for subsequent reapplication depends on the sealer, exposure and use rather than a fixed interval that applies to all sandstone.

[edit] Quality and natural variation

Natural stone is inherently variable, and colour, grain, mineral inclusions, texture and other characteristics can vary within a quarry and between different production batches. A sample should therefore be regarded as an indication of the expected material rather than a guarantee that every slab will be identical.

For significant projects, inspection of representative material and review of relevant technical test data can help establish whether the stone is appropriate for the intended application. Particular attention should be given to the stone's performance in relation to the environmental exposure and loading conditions of the project.

[edit] Related articles on Designing Buildings

• Natural stone
• Choosing stone
• Patio stone
• Natural stone paving
• Natural Stone Tiles
• Natural stone flooring
• Natural stone cladding
• Types of stone
• Patio
• Sourcing indigenous stone