Your burning questions, answered. Over the past three decades, we have found our clients share a number of the same stone-related wonderings. So, here, we have gathered them all and detailed our expert advice. And if there is something we have missed, or if you would rather discuss your question in more detail, our stone and tile specialists are always at the other end of the phone.

What colour grout should I use for my stone and/or tile?

Grout colour is very important as it can make such a difference to the overall look of the floor or wall. Although very much a personal choice, we would always recommend choosing a colour that blends with the stone or tile, so that you are focusing on the tiles not the grout joints. However dependent on the tile you use, there are grout colours available to make the area more of a feature.

What does the slip rating of a stone/tile mean?

Most tiles are assigned a slip rating and based on this rating you can assume which tiles are suitable for your project, for example, a high-slip resistant tile is suitable for a wet environment or external environment where the risk of slipping is greater. There are two different ways slip testing is done with some materials having a PTV rating and some a R rating.

What are PTV / R ratings?

PTV stands for pendulum test value, which essentially measures how slippery a floor surface is when a foot comes in contact with it. PTV also calculates slip-resistance. It is measured with a pendulum that mimics a shoe on a surface. The results will determine the PTV or R rating and thus the suitability of the tile, for example:

PTV 11 - 18 (R9) - low friction. Suitable for dry internal domestic floors such as kitchens, dining areas and hallways.

PTV 18 - 34 (R10) - medium friction. Suitable for internal domestic floors subject to occasional wetting, such as bathrooms.

PTV 34 - 51 (R11) - high friction. Suitable for external areas such as patios, walkways, dressing rooms and pool surrounds.

How does a pendulum test work? (PTV rating)

Two types of rubber are used to measure the resistance of barefoot and footwear. The slides make contact with the tile in the same manner as a human heel would at the point that slips occur. After striking the test surface, the foot swings and a measurement is taken to see how the friction of the surface reduces the energy of the foot. The test is conducted in both dry and wet conditions. A tile with a high slip resistance has a lower probability of a slip.

How does a ramp test work? (R rating)

First of all a ramp is covered with the flooring material that is to be tested. The ramp angle then increases in degrees until the tester, who is either barefoot or wearing a predetermined shoe type, slips. The test is then repeated on dry floors, wet flooring and contaminated floor surfaces. The results of the tests performed are averaged and the floor material is given an R rating.

When will my special-order product arrive?

We work with many factories all over the world, and when a bespoke i.e. specially made product is ordered, lead times can vary due to manufacture time with the factory workers carefully manufacturing your order (sometimes by hand) and of course shipping time. The journey of a material from source to delivery has many processes. We always recommend that if a project is time critical, to have a look at our many wonderful stock products that are generally readily available, to avoid delays as these do happen and are outside of our control.

How should I cut my tiles?

Tiles should always be installed by a dedicated professional who is used to dealing with these products due to different materials needing different care, tools to cut, and installation. Natural stone and tiles can be cut using a diamond blade – ideally a water-cooled machine. Some porcelain, glass and ceramic tiles can be cut with a scribe and break type cutter. Tiles which are extremely thin, require various specialist tools due to having less surface tension, such as glass cutters and manual tile cutters, along with a tile cutter ruler. A specialist frame used alongside a hand-held angle grinder may also be required.

Can the driver take my goods into the property and help unpack?

No unfortunately not. The delivery service we offer is kerbside delivery via a tail lift courier, once unloaded the goods are the responsibility of the site team. The delivery driver is not insured to help handle the goods, move the goods into the property or remove packing, therefore it is essential someone is present to receive the order.

What tiles require sealing?  

Natural stone and terracotta tiles do require sealing with the appropriate sealant (water based only for external use and water based or solvent based if internal). For natural stone a minimum of two coats is required, once prior to grouting (to protect the tiles throughout the grouting process) and once after grouting (include sealing the grout joints). Terracotta being more porous will require triple, sometimes quadruple the amount of sealant, as well as finishing with a wax topper. Porcelain and ceramic tiles do not require sealant unless they are crackle glaze, but you can choose to seal the grout lines to help protect these from staining.

What does rectified and non-rectified materials mean?

Rectified applies to porcelain or ceramic tiles that are cut to size after the firing process. Rectified tiles are ‘dimensionally stable’ and will exhibit little variation in size of tiles from one production run. Non-rectified applies to porcelain or ceramic tiles that are not cut to size after the firing process. The firing process then causes expected shrinkage and warpage. Because of this greater variation in size between tiles should be expected than with a rectified tile.

What is the difference between a crack and a fissure with natural stone?


A crack is a broken piece of material, which is most of the time, chipped, uneven or separated and is usually the result of man-made stresses. A fissure is a thin line of mineral veining which normally contrasts with the base colour of the stone and so can be mistaken for a crack in the tile. One way to help distinguish between the two is by running your fingernail across the surface, when doing this across a fissure your nail should glide over smoothly as a fissure doesn’t change the surface of your stone top, when running your fingernail over a crack, your nail will not glide smoothly as there will be a noticeable unevenness.