Granite v marble flooring

[edit] Introduction

Granite and marble are natural stones commonly used for internal flooring. Both can provide durable and visually distinctive floor surfaces, but their geological composition, hardness, porosity, appearance and maintenance requirements differ.

Granite is an igneous rock formed from the slow cooling and solidification of magma. It commonly contains quartz, feldspar and mica and tends to have a granular appearance. Marble is a metamorphic rock formed when limestone or other carbonate-rich rock is altered by heat and pressure. It is predominantly composed of calcite or dolomite and is often characterised by crystalline texture and veining.

The suitability of either material depends on the intended application, expected foot traffic, moisture exposure, surface finish, installation system and maintenance requirements.

[edit] Characteristics of granite and marble flooring

[edit] Granite flooring

Granite is generally a hard and durable natural stone and is widely used for floor tiles and other high-wear applications. Its mineral composition and relatively high resistance to abrasion can make it suitable for areas subject to frequent foot traffic.

Granite is available in a wide range of colours and patterns, including grey, black, pink, white, green and other shades depending on its mineral composition. The pattern is generally granular or speckled, although individual stones can vary considerably.

Granite flooring can be used in:

• Entrance areas and hallways.
• Living areas.
• Kitchens.
• Circulation spaces.
• Commercial interiors.
• Other areas subject to substantial foot traffic.

The performance of a particular granite depends on its mineral composition, porosity, thickness, surface finish and installation. Natural stone should therefore be assessed for the intended application rather than assuming that all granite has identical properties.

[edit] Marble flooring

Marble is commonly selected for flooring because of its colour, crystalline texture and natural veining. The appearance can vary substantially between different varieties and individual tiles, making sample selection and control of acceptable variation important.

Marble can be used for:

• Entrance areas.
• Hallways.
• Living areas.
• Bathrooms.
• Kitchens.
• Feature flooring.
• Other internal applications where its appearance and performance are appropriate.

Marble is generally softer than granite, particularly where it is predominantly composed of calcite. It can therefore be more susceptible to scratching, abrasion and surface wear. Calcite-rich marble is also sensitive to acids, which can cause etching and loss of surface polish.

Marble can be supplied with polished, honed and other finishes. The selected finish affects both its appearance and performance, including the way wear and surface marking become visible.

[edit] Comparing performance and maintenance

There is no universal choice between granite and marble because the appropriate material depends on the requirements of the particular floor.

Granite is generally preferable where resistance to abrasion and frequent foot traffic are significant considerations. Marble can also provide durable flooring when appropriately selected and maintained, but its greater susceptibility to scratching and acid etching needs to be considered.

[edit] Cleaning and sealing

Both granite and marble flooring should be regularly cleaned to remove dirt and abrasive particles that can contribute to surface wear. Cleaning products should be compatible with the particular stone and its finish.

Acidic cleaning products should generally be avoided on marble, particularly calcite-rich marble, because acids can react with the calcium carbonate in the stone and produce etching. Care should also be taken with substances such as vinegar and other acidic household products.

Granite is generally less chemically sensitive than calcitic marble, but some granite varieties can still be affected by unsuitable cleaning products or staining substances.

The need for sealing depends on the characteristics of the stone and the intended application. More absorbent stones may benefit from an appropriate impregnating sealer to reduce staining and moisture penetration. Sealing does not make natural stone completely stain-proof or eliminate the need for routine maintenance.

[edit] Surface finish and slip resistance

The finish applied to natural stone affects its appearance, maintenance and slip characteristics. Polished stone has a smooth, reflective surface and is commonly selected where a formal appearance is required. Honed stone has a less reflective, matte surface.

The suitability of a finish should be assessed in relation to the intended location. Areas that may become wet require particular consideration because surface texture and contamination can affect slip resistance. A highly polished finish may not be appropriate for every flooring application.

Technical information for the specific stone and finish should be checked before selection, particularly where slip resistance, moisture exposure or heavy foot traffic are important considerations.

[edit] Appearance and natural variation

Natural stone is subject to variation in colour, veining, grain and texture. Granite generally has a granular appearance resulting from its constituent minerals, whereas marble can have pronounced veins and crystalline patterns.

Individual tiles may therefore differ from samples or from one another. Where appearance is important, a representative range of samples should be examined before specifying the material. The intended laying pattern should also take account of natural variation.

[edit] Selecting between granite and marble

Granite may be appropriate where the principal requirements include:

• High resistance to abrasion and regular foot traffic.
• A granular or relatively consistent natural appearance.
• A wide range of colours and mineral patterns.
• A flooring material that generally requires less protection from acidic substances than calcitic marble.

Marble may be appropriate where the principal requirements include:

• Distinctive natural veining and crystalline texture.
• A decorative or formal appearance.
• A wide range of colours and patterns.
• A material whose natural variation forms an important part of the design.

In either case, the specific stone should be assessed rather than relying solely on its generic classification. Relevant considerations include hardness, porosity, staining susceptibility, surface finish, expected traffic, moisture exposure, cleaning requirements and compatibility with the proposed installation system.

Natural stone flooring can provide a durable and long-lasting surface when the material is correctly selected, installed and maintained. The differences between granite and marble mean that the choice should be based on the technical requirements of the floor as well as its intended appearance.

[edit] Related articles on Designing Buildings

• Natural stone flooring
• Natural Stone Tiles
• Natural stone
• Choosing stone
• Choosing floor tiles
• Floor tiles
• Types of tile
• Types of stone
• Natural Stone for Interiors
• Defects in stonework