All About: Stone Flooring

Why Choose Stone?

Natural stone, with its flaws and unique character, has something not found in man-made materials

Natural stone floor tiles have a beauty and sense of warmth that is not often seen in man-made materials. This is in part due to the individual nature of each tile, and the character and texture that comes with the fossils, pitting and mineral striations – something ceramic tiles lack – that are present in many stones.

As a floor covering, stone works well in pretty much every area of the home, and those concerned about it feeling cold underfoot should bear in mind that it works extremely well with underfloor heating. Some stones are also inherently warmer than others, with limestone, for example, feeling warmer than slate.

The range of stone variations on offer is huge, with every colour and finish being covered by one stone or another. So, whether your home is contemporary or traditional, you will find a stone to suit — be it a white, honed limestone for your hi-tech kitchen or an opulent polished marble for your luxury bathroom.

Stone is not always as expensive as you might think, either: depending on the variety and finish, prices start at £12/m².

Choosing Size, Stone & Weight

Large-format tiles can be very heavy, so check your floor structure

The size and shape of the stone floor tile you opt for is entirely up to you — the choice is indeed huge. Stone is available in sizes from the tiniest of mosaics, measuring as little as 25 x 25mm, to large-format slabs of more than 600 x 600mm. Shapes vary from the standard square tile, to rectangular tiles in a number of widths and lengths. If you have a particular shape in mind, it is also possible to have stone tiles cut to order, at an extra cost.

Some suppliers offer packs made up of tiles of various lengths and shapes designed to be laid in a particular pattern. Rectangular tiles, particularly those that are very long and narrow, can be useful in smaller rooms, where laying them horizontally can create the illusion of a wider room. Bear in mind, too, that the smaller the tile, the more grouting there will be to carry out. If you plan to lay your tiles on a DIY basis, take into account the weight of some of the large-format tiles. It is not unusual for them to weigh up to 14 pounds each, so do check your joists will take the added load — not to mention your back.

ABOVE: Lapicida’s White Limestone, £97.46/m² (01423 400100)

Laying -  DIY or Pro Job?

Laying stone flooring is far trickier a job than laying ceramic tiles

Laying a natural stone floor is not a DIY job for the faint-hearted. Unlike most ceramic tiles, stone tiles often come with flat edges, as opposed to slightly rounded ‘cushion-edge’ ones. This means that the quality of the laying must be of a really high standard, particularly if you want narrow joints (this usually looks best with large-format tiles), if the final result is to look neat. Check with your supplier, as it is possible to buy stone tiles with a bevelled edge, too.

Add to this the often quite hefty weight of some stone tiles or the intricate nature of mosaics, the care that must be taken in finishing the tiles properly and the fact that you will usually have paid considerably more for your stone tiles than you would have done for ceramic, and you can see why many people choose to call in the professionals for this particular job. It is not always easy to find a tradesperson with experience of stone flooring, as many are more familiar with ceramic — so check yours has the correct knowledge.

If you do choose to take on the job yourself, be aware that you will need to buy or hire specialist tools for the task, as a regular tile cutter is unlikely to be suitable for cutting stone. An electric wet circular tile saw is one of the best options, with a water bath in which the lower half of the blade runs, providing lubrication and stopping the blade from overheating.

ABOVE: Noisette Riven Slate, from Mandarin Stone, from £22.22/m² (01600 715444)

Need to Know...

Adhesive & Grout

• You should always check what kind of adhesive will be suitable with your supplier, but it is usually recommended that a flexible polymer-modified cement-based adhesive be used for stone floor tiles to account for movement.

• For large-format tiles, large format flexible floor adhesives are available. Light stones should be fixed with white adhesive to prevent discolouration.

• Cement-based grouts are usually recommended for stone tiles. The colour you choose will obviously depend on the type of stone you have opted for, but light-coloured or matching grouts tend to look best with lightcoloured limestones, marbles and travertine. Slate can look great when combined with contrasting light-coloured grouts. Mandarin Stone’s website (mandarinstone.com

Finishing & Maintenance

• Although the degree of porosity varies depending on the stone, all natural stones are porous and should be sealed to increase stain resistance.

• Limestone, travertine and marble should be clean and dry before applying a coat of appropriate sealant with a brush or sponge — this should be carried out before grouting. After grouting, a further one or two coats should be applied. Residue should be removed immediately.

• A further two coats of liquid wax surface sealant are also recommended.

• Slate is less porous and so requires only a liquid wax surface sealant: one application before grouting and one after. Some stones, including sandstone and limestone, are very porous and so will need several coats of sealant.

The Different Stones

Limestone

A hugely popular stone for flooring at present – particularly in its palest forms – limestone varies in colour from white and pale grey through to grey/blacks. It tends to feature prominent fossils, mineral striations and sometimes pitting. Ensure you seal it well to avoid stains.

Travertine

Travertine varies in colour but usually comes with lots of surface pitting and voids. It is available from some suppliers ‘filled’ or ‘unfilled’. ‘Filled’ versions have any surface voids filled with colour-matched resins, whilst ‘unfilled’ are filled with grout during the fitting process. Travertine is in fact a very hard and compact type of limestone.

Marble

Marble comes with characteristic mineral veining, usually being of a contrasting colour to the base colour. Marble lends itself well to a highly polished finish, but beware of this in the bathroom, where it can become slippery when wet. In heavily veined tiles, a meshed backing may be applied to in order to strengthen it.

Slate and Schist

Slate comes in two forms, ‘riven’ and ‘honed’. Riven slate has a naturally cleft surface and is well suited to more rustic, traditional interiors. Honed slate is machine finished to provide a smooth, even appearance, well suited to modern schemes. The uneven nature of riven tiles means that they may need to be bedded up when laid in order to achieve an even finish.

Sandstone

Sandstone has a granular surface and is usually a warm, honey colour. Sandstone is very porous and requires thorough sealing.

Granite and Basalt

Granite is one of the hardest stones available for flooring. It is usually given a polished finish which shows up the crystals within the stone. Basalt is formed from volcanic lava flows and is comprised of tiny crystals. Granite is one of the most expensive stones.

ABOVE: Mandarin Stone’s Beauvillon Brushed Limestone, from £89/m² (01600 715444)

Buying Stone Flooring

Where to Buy

There are many sources of stone tiles. Specialists stone retailers are the obvious option, but many DIY warehouses now also stock stone. Some local stone quarries supply stone for flooring, although many specialise in just external products.

Prices

Prices vary and what you pay will very much depend on the quality and appearance of the stone, sizes, its source and where you buy it from. Based on a tile size of around 300 x 300mm, the prices below are an approximate guide. Most prices for the products in this article will not include VAT:

• Limestone – £30/m²
• Travertine – £25-30/m²
• Marble – £30/m²
• Slate – from £15/m²
• Schist – £25/m²
• Granite – £40/m²

All prices correct as of May 2010.

Further Reading:

• How to Lay Floor Tiles 
• Wooden Flooring
• Choosing Your Floor Structure