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A Comprehensive Guide to Slate Roofing


30th January 2018

There are a variety of options within slate roofing and sometimes the difference between these options can seem confusing. From cost and durability to how many tiles will be required and how easy they are to install. Read on for more information on the various types of slate roofing available and the things you should consider when deciding on the type of slate you are going to use.

What are the Different Types of Slate Roofing?

As with roofing tiles, there are plenty of options available for those who prefer the more natural finish offered by slates. The use of slate roofing is very popular across the UK both for its cost-effectiveness and appealing aesthetic.

An Example of Slate Roofing - Roof Stores
An Example of Slate Roofing

When looking at choosing slate for your next roofing project it's worth knowing what's available. This involved getting to know the three main types of slate available to buy:

  • Natural Slate: Sourced and taken from natural environments to produce a stunning finish.
  • Fibre Cement Slate: Made primarily from cement and other elements and is a versatile, cost-effective option.
  • Man-made Slate: which is largely made up of reconstituted slate and is a cheaper alternative to the natural version.

What are the Benefits of the Different Types of Slate?

To make it easier to understand the differences between the three types of slate – natural, fibre cement and man-made – we’ve separated each one into its own section.

Natural Slate

What are the Benefits of Natural Slate?

Similar to clay, natural slate offers a truly authentic look that cannot be replicated by manufacturers. For period projects, or properties that need to reflect the natural environment around them, natural slate is usually the preferred choice. Its lifespan goes beyond both clay and concrete by some distance and has even been known to outlast the structure of the very buildings they have been placed upon.

SIGA Natural Slate - Roof Stores
SIGA Natural Slate

In terms of performance, natural slate does not fade or deteriorate over time, which is reflected in how long it will protect the roof structure. Another great advantage this type of slate offers is its low maintenance, which means very little ongoing effort will be needed to keep them in good working order.

How Long Do They Last?

The properties of natural slate mean that it is extremely durable against even the harshest of weather conditions, which guarantees an extremely long lifespan. It can last anywhere up to 150 years, although there have been many occasions where it has lasted far longer.

How Much Do They Cost?

This section is intended to provide you with an idea of the level of pricing for natural slate which can range from approx: £1.03 to upwards of £2.00 per slate. To see the most up to date prices on individual products, follow the links below or visit our natural slates page.

Much will depend on the type of slate purchased and, of course, the quantity required, as bulk purchases can help bring down the overall unit cost. Some types of slate are higher quality than others and so will cost more, such as imported Spanish slate compared to man-made cement slate mimics.

To see example pricing for imported Spanish slate take a look at the SIGA 35 Natural slate and SIGA 114 Natural slate.

What is BS EN 12326?

This is the European Standard that states the performance levels and quality of slate tiles. There are two parts to these regulations which came in during 2004. First is BS EN 12326-1, which details product specification, and second is BS EN 12326-2, which illustrates the methods of testing used to demonstrate the materials quality.

Why Does Carbonate Content Matter?

When purchasing natural slate, the manufacturer will detail how much carbonate content is found in the material itself. This is important because it reflects the quality of the slate you are purchasing. Slate with a high carbonate content, usually over 20%, can affect the colour in the short term, turning lighter slate tiles darker once exposed to the elements.

Spanish Slate

The import of Spanish slate has grown exponentially over the past few decades due to its combination of cost-effectiveness and aesthetic appeal. SIGA is one of the leading suppliers of Spanish slate in the UK and offers warranties up to 75 years on some of their ranges.

SIGA 32 Spanish Slate - Roof Stores
SIGA 32 Spanish Slate

They supply four different brands in total: Excellence, Specification, Commercial and Classic, with each recommended for use with specific types of build and project. The cost is higher for the more superior end of the range but this is balanced by less wastage being produced and shorter installation times.

How Many Natural Slates Do You Need Per Square Metre?

As with any tile or slate, this will be determined by the item purchased. The table below gives you a few examples to help give you an idea.

Type Size Tiles Per Square Metre
SIGA 35 Natural slate 400 x 250mm
400 x 375mm
25 tiles per m²
SIGA 56V Natural Slate 500 x 250mm 20 tiles per m²
SIGA 114 Natural Slate 500 x 250mm
500 x 375mm
20 tiles per m²

What is the Minimum Pitch for Natural Slate?

The minimum recommended pitch for natural slate is 25°, although this can be lowered down to 20° with products like the SIGA 56M Natural slate and is also dependent on slate size.

How Easy is Natural Slate to Install?

Installing natural slate is a more specialist job than most other kinds of roof covering. Companies who are well versed in both British Standard 5534 and BS 8000 Part 6 will ensure they have the right level of experience to install a natural slate roof. Slate can only be installed onto a pitched roof (at the minimal level recommended above) and depending on the complexity of the structure, can take anywhere from one week up to a few weeks or even longer.

Fibre Cement Slate

What are the Benefits of Fibre Cement Slate?

Although fibre cement slate cannot match the distinct beauty that natural slate provides, it still adds real value. They are made from a mixture of cement, fibres and mineral additives and provide further options across a greater range and type of roof structure.

Marley Birkdale Fibre Cement Roof Slates - Roof Stores
Marley Birkdale Fibre Cement Roof Slates

Fibre cement slate is lighter in comparison to natural slate which is good news for the supporting underlay. They can be used on both steeper and lower pitches and roofs that require a more complex design such as valleys or intersections.

How Long Do They Last?

The longevity of fibre cement slates will be similar to tiles that are made of cement. You can expect a guarantee of 30 years from the manufacturer but in many cases, they will last at least twice as long, up to 60 years. Annual maintenance and favourable local weather will also allow fibre cement slates to live on for a much longer period.

How Much Do They Cost?

This section is intended to provide you with an idea of the level of pricing for fibre-cement slate which can range from approx: £1.00 to upwards of £3.00 per slate. To see the most up to date prices on individual products, follow the links below or visit our fibre cement slates page.

Due to the material used in the manufacturing process, fibre cement slates are a more cost-effective option than natural slates. This is good news for people working on a tight budget and for building companies who also have to carefully watch their margins.

The Cembrit Jutland fibre cement slate has an attractive starting price for the 600 x 300mm variant and also comes with pre-drilled holes for great adaptability. Although slightly more expensive, the Marley Birkdale slate can be used on pitches as low as 15° if required.

How Many Fibre Cement Slates Do You Need Per Square Metre?

Fibre cement slates come in a range of different dimensions and the table below lists some to give you an idea of how many you may need for your roof.

Type Size Tiles Per Square Metre
Cembrit Jutland 600 x 300mm 13.3 tiles per m²
Marley Birkdale slate 600 x 300mm 13.3 tiles per m²
>Cembrit Zeeland 600 x 300mm 13.3 tiles per m²
Marley Thrutone 600 x 300mm 13.3 tiles per m²

What is the Minimum Pitch for Fibre Cement Slate?

The cement base of the slate allows for greater flexibility with regards to minimum pitch levels. The Marley Birkdale slate mentioned above can be used on pitches down to 15°, and another example is the Marley Thrutone which also can be laid as low as 15°.

How Easy is Fibre Cement Slate to Install?

Another great benefit fibre cement slates provide is they are designed to reduce installation time. They are purchased with pre-drilled holes which will mean less time spent laying the slates, reducing the overall labour costs that come with it. The time and money saved help the company to be more efficient and allows the property to enjoy the benefits of their new roof much faster.

Man-made Slates

What are the Benefits of Man-made Slate?

Made from a combination of ground down slate and synthetic resin, man-made slate offers another alternative to both natural slate and fibre cement slate. The low cost of these tiles is the main advantage they offer, set at very affordable prices in comparison to the other types available.

Cembrit Westerland Man-made Slates - Roof Stores
Cembrit Westerland Man-made Slates

The larger size of man-made slate is another cost saving benefit that means purchasing costs are smaller and the installation required is a lot faster and cheaper. They are very lightweight which will reduce the need for extra reinforcement in the underlay and the recyclable nature of the materials makes them a very eco-friendly choice.

How Long Do They Last?

Similar to clay or concrete tiles, man-made slates are designed to last for up to 30 years in normal weather conditions. When the cost-effectiveness of this type of slate is added into the equation, man-made slate becomes a very attractive option for many buyers.

How Much Do They Cost?

This section is intended to provide you with an idea of the level of pricing for man-made slate which can range from approx: £1.24 to upwards of £40 per slate. To see the most up to date prices on individual products, follow the links below or visit our man-made slates page.

The price is often a key deciding factor for many buyers when it comes to committing to this particular type of slate. Their durability, use on low pitched roofs and natural-like appearance also makes them strong value for money.

The Redland Cambrian Grey slate is a good example of man-made slate, as it is composed of 60% of natural slate, the slate also comes with interlocking ability. While it's a more costly option due to the processes and materials that go into its manufacturing, this versatile slate can be used on pitched roofs at 15°.

Sandtoft's Britslate Countess slate is made up of 80% natural slate and its natural appearance continues to make it a popular customer choice, as does its reasonable price.

How Many Man-made Slates Do You Need Per Square Metre?

Man-made slate is generally produced at a larger size than natural slate making it easier to install and an all-around cheaper alternative. You can use the table below as quick size guide to help.

Type Size Tiles per square metre
Redland Cambrian Slate Grey 300 x 336mm 13.3 tiles per m²
Sandtoft's Britslate Countess slate 510 x 255mm 20 tiles per m²
Sandtoft Rivius Slate 418 x 335mm 9.5 tiles per m²

What is the Minimum Pitch for Man-made Slate?

Man-made slate provides great versatility for installers. The Redland Cambrian Grey slate mentioned above can be pitched at 15° due to its interlocking technology. While the material can only match the appearance of natural slate up to a certain point, the ability to use it at lower pitches allows for use on a wider range of property types.

How Easy is Man-made Slate to Install?

As is the case with fibre cement slate, this variant can be installed quickly and with relative ease. Many are now manufactured with interlocking technology and because the tiles are of a larger size, the installation and labour time is significantly reduced.


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