The Tile Guide
The plain tile is a small rectangular flat tile measuring 265mm x 165mm (or 10½" x 6½" x ½"). The size of plain tiles was set way back in 1477 by King Edward IV and it does not vary much from that today.
Plain tiles are laid with a broken bond and keep out the water by over lapping each other 3 tiles deep. This results in only the bottom third of each tile being visible once laid. Tiles that are laid this way are known as double lapped, and take their looks from this method of installation.
In addition to the standard tile, plain tiles require a ‘tile and a half’ or gable tile to be used down the verges (each side of the roof slope). They also require special ‘eaves’ tiles, used on the bottom course (row) of tiles. Further specially moulded tiles are required for use at the valleys and hips.
The fine detail offered by plain tiles makes them one of the most attractive roof coverings available. The look they create is often considered traditional, however they can also work well with modern house design, especially when made of clay. Plain tiles are also perfect for cladding and are often used for vertical tiling on exterior walls, particularly in the South East.
As a result of their small size and the fact that they do not interlock, plain tiles require around 60 tiles per m² so can be labour intensive to install. Also there are up to three times more battens per m² compared to interlocking tiles and the weight on the roof is significantly greater.
There are a number of different tile types that vary in price and aesthetics:
Handmade Clay Plain Tiles - at the upper end of the price range are handmade clay plain tiles, where every tile has its own character, adding a rich texture to the roof, both in terms of colour and shape. Handmade plain tiles are normally lightly sanded which further adds to their charm. As they are made of clay, the beauty of the roof will never fade but mature slowly with age.
Handcrafted Clay Plain Tiles - the handcrafted term refers to machine made plain tiles that have been carefully designed to have a handmade appearance, but at a more affordable price. Like the handmade variety, these tiles usually have a sanded texture and are available in similar colours. Over the years the appearance of such tiles has improved, thanks to more sophisticated manufacturing techniques which can achieve levels of character and texture that more closely resemble handmade plain tiles.
Clay Plain Tiles - machine made clay plain tiles are available in a wide range of colours in the red/brown spectrum and all the way through to black. They usually have a smooth finish and are either double or single cambered. They generally cost 20% more than the concrete plain tiles.
Concrete Plain Tiles - concrete plain tiles are the same size and shape as clay plain tiles and are available in colours that seek to mimic the clay plain tile appearance. The price of a concrete plain tile is generally slightly less than standard clay equivalents. Having said that, it is worth noting that the pigmented colour of concrete will fade over time.
Interlocking Plain Tiles - in an effort to reduce labour costs and use less material and energy, manufacturers now offer a number of interlocking hybrid plain tiles which require fewer tiles per m². Clay interlocking plain tiles such as Sandtoft's 20/20, have proved particularly popular as they create a plain tile appearance for less than the price of a concrete plain tile. Such are the savings in material and labour, that these tiles reduce roof costs by around 40%. Interlocking plain tiles can also be laid at lower pitches than traditional plain tiles, which makes them perfect for extensions and additions.
Original Traditional Pantiles are usually made from clay and in cross section are rather like a flattened “S” shape. This shape creates a distinctive flowing appearance that over the years has given pantiles the reputation for being one of the UK's great vernacular roofing materials.
Pantiles were originally made from clay until the 1950s when more cost effective concrete pantiles appeared. The design of the concrete pantile is very similar to traditional clay pantiles however there are some aesthetic differences, which is why planners will not always permit the use of the concrete version. The concrete pantile has a thicker and rougher front edge of 30mm. (compared to 15mm for a traditional clay pantile and around 20mm for an interlocking pantile). The other key difference is colour, clay pantile colours have a more natural appearance and as they are fired in a kiln, will not fade over time like concrete products will.
Pantiles are generally found down the east coast of England and Scotland and in pockets around the South West. This geographic spread began around the 16th century when trading ships exported textiles to Holland and Belgium and returned to ports like Ipswich and Hull with clay pantiles.
As a result of the geographical nature of pantiles not all roofers will know how to install them. If you are outside or on fringes of a pantile area it is worth ensuring that you talk to a contractor who has experience laying such products.
Handmade Clay Pantiles - today handmade clay pantiles are only manufactured in small volumes, as planners are usually satisfied with the traditional machine made variety.
Traditional Clay Pantiles - one of the country's classic roof tile designs. The way traditional pantiles overlap means that they have a thin and continuous leading edge that adds to their charm.
Interlocking Clay Pantiles - an evolution of the traditional pantile, the interlocking pantile, has interlocks and weather bars which enable it to perform down to lower pitches. These products have a thicker leading edge and are slightly cheaper than the traditional alternative.
Concrete Pantiles - pantiles became available in concrete the 1950s and are the most cost effective single pantile. The concrete pantile is very similar in design and size to the clay original, but usually can be identified by a thicker front edge and a less natural colour.
Clay Double Pantiles - the clay double unit pantile was only introduced in 2008. This recent innovation represents a significant reduction in the cost of a natural clay roof, only costing 30% more than concrete double pantiles.
Concrete Double Pantiles - concrete pantiles have existed in double unit form since the 1960s and have been popular due to labour and time saving benefits. The concrete double pantile is one of the most cost effective roof coverings available and hence one of the most popular roof tile shapes in the UK.
The profile of the Roman tile design is a flat shape with a small roll running down the right hand side of the tile. Like pantiles, Roman style tiles are available in single and double form, however unlike pantiles, the use of clay single Roman tiles is relatively limited. It is more common to see double roman roof tiles, particularly in concrete, which historically is the most popular tile design in the UK.
The original design of a Roman style tile evolved in a similar way to the pantile, from a more labour intensive predecessor known as Tegula and Imbrex tiles. The flat tile and the curved tile were joined together to form a single unit. Early versions had a similar look to the Tegula and Imbrex with a large pronounced roll (such as Bambino tiles) however models exhibiting a smaller more delicate roll became the norm. This most popular of these was the Sterreberg or Flemish tile which was imported from Belgium in large numbers in the 1950s.
The clay double Roman has a long history and was popular, particularly in the South West until production ceased around 50 years ago. Since then the market consisted of mostly second hand product, until the recent addition of two clay double roman models from Sandtoft.
Clay Single Roman – imported in large numbers in urban areas in the 1950’s and recently re-introduced by Sandtoft under the Koramic brand, as the Tempest 44. A similar product is offered by Imery's.
Traditional Clay Double Roman – Sandtoft are the only manufacturer offering a traditional clay double roman, the Bridgwater, which is generally used for conservation projects.
Interlocking Clay Double Roman – another recent innovation, the clay double roman achieves the same benefits as the clay double pantile, in providing an affordable clay alternative to concrete. Currently the only such product is the Modula, from Sandtoft.
Concrete Double Roman – all major concrete manufacturers offer a concrete double roman which has held the position as the most popular roof tile for many years.
Slates and Slate Alternatives
The term slate can have two meanings, it can refer to the actual material, but it is also be used as a loose term to describe a type of roof material with a thin, flat appearance and (usually) a blueish/grey colour.
Natural slates - are essentially thin sheets or slabs of metamorphic quarried rock that are laid double lapped, with each slate nailed to the batten or secured using special slate hooks. Slate has been used as a roofing material since Roman times and comes in many sizes, thicknesses and levels of quality, which varies from region to region. The UK slate industry peaked in the 1980s, and today there are only two active quarries in Wales and small scale specialist production in Devon and the Lake district. Most slate now tends to be imported and comes from countries such as Spain, China, Canada and Brazil. Despite most of the imported slate moving abroad, slate from this country has maintained a reputation for being of the highest quality and durability. Welsh Slates from the Penrhyn, Ffestiniog, and Cwt-y-Bugail quarries remain popular and are known to be the finest roofing slates in the world, adorning many of our nation's finest buildings. Examples include Buckingham Palace, No.10 Downing Street and St Pancras station.
There are a number of alternatives to slate that have been developed to look similar and cost less. The most common alternatives are made from fibre-cement and concrete. Whilst both materials offer savings over the cost of slate they cannot compete with the aesthetics of a natural quarried slate. Some interesting and more aesthetically pleasing alternatives exist in recycled slate and natural clay.
Thin leading edge clay and concrete tiles – Thin leading edge tiles began in concrete and more recently became available in clay. The tiles come in slate colours and have been designed with a thin front edge, to look more like slate. This thin leading edge is nearly half the thickness of standard flat concrete tiles, which are often rejected by planners for appearing too heavy on the roof. This group of tiles come at a 30% premium over standard concrete, but despite this, are still half the cost of a slate roof due to the material and labour savings. Clay thin leading edge tiles are a recent innovation by manufacturers, such as Sandtoft, to take advantage of the versatility of clay in providing a high performance labour saving slate alternative that, like slate, will not lose its colour over time.
Fibre-cement – Fibre-cement was invented in the 1890s and uses layers of cellulose, reinforcing fibres and cement. These slates have the same form and thickness as natural slate, and offer value for money, but cannot match slate's durability, or longevity of colour.
Reconstituted / Recycled slates – these products are made of crushed slate and other aggregates and pressed in the format of an interlocking tile. Despite the fact that these products are tiles not slate, because they are so thin, they still achieve an appearance close to that of natural slate. A big benefit of recycled slates is that they make use of the large amounts of waste material that is generated when quarrying slate. These products are offered by most of the leading manufacturers, however be aware that the recycled slate content varies from as high as 80% down to much lower figures.