Which Slate or Tile is best suited for your roofing project?
Which slate or tile is best suited for your roofing project?
Whilst on the surface slates and tiles seem very straightforward, they actually lead to a rabbit hole of misinformation and complexity. In this article we hope to give you a brief understanding of what the difference between a slate and a tile is and share some of our knowledge surrounding the subject.
We hope to give you a clearer idea of the different type of options available, the difference in weights, application and costs and enable you understand what slate or tile is most suited for your roofing project.
Slates and Tiles
There are two fundamental type of slates and tiles; double overlapping and single overlapping. Double overlapping means that for the system to be effective, each tile of slate has to overlap two others. This is the case with traditional slates and plain tiles.
Single overlapping means that the tiles or slates only overlap one other. This is the case with large profile interlocking concrete tiles and clay pan tiles. Double overlapping tiles and slates cannot be used on low pitches whereas single overlapping tiles and slates can.
So what is the difference between a slate and a tile?
Well if you want to be pedantic, a slate is made from Slate which is a fine grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism.
But we also know that people call some man made products slates, these are usually imitation products, often made from fibre cement materials. For the purpose of this article because these are fixed with a ‘double overlap’ we will include them under slates.
People also call some single overlap man made products slate these are often made from a mixture of reconstituted slate dust and resin and look almost identical to real slates once they’re fixed. This is a clever design, allowing the appearance of slate and the ability to be used at lower pitches.
Technically, they are not slates. And flat, grey, single interlocking concrete tiles, which sometimes vaguely look like slates, are definitely not slate. All these products are designed to meet the different needs of customers and all have their place. There really is something for almost every situation.
So slates are cut from naturally occurring rock, have double overlap and rely on mechanical fixing to stay on the roof. Usually two copper or aluminium nails. They come in a variety of sizes and colours but by far the most common, especially these days, are 250mm x 500mm or 20” x 10”.
Larger patterns such as 300mm x 600mm or 24” x 12” are less common because, it is harder to find veins of slate from which large numbers can be quarried. Although available in greens and browns, the most common colour we see is grey.
Tiles on the other hand, are usually made from concrete or clay and can be fixed in position by nib like projections which hook over timber battens. They can also be nailed and clipped. They can be single or double lap and have a huge variety of shapes, sizes and colours.
Clay tiles can even be glazed. And we come back to cost again. Well you get what you pay for as they say, and no matter how much you would like to use them, if the Client has a low budget you are not going to be specifying handmade clay tiles or Welsh slates.
At the lower end of the price range are concrete interlocking tiles, although these days the more stringent fixing requirements of BS 5534 has reduced this cost advantage somewhat. But if you consider that larger tiles in these ranges have a covering capacity of 10 per SQM, whereas plain tiles require 60 to cover the same area, you can see where some of the additional cost comes from. Natural slates are more expensive than man made slates but are much more durable.
Concrete or Clay?
This used to be a much easier choice. Early concrete tiles weathered badly, the colour washed out of the surface and they could look quite brutal. So aesthetics would often rule in favour of clay. But these days’ manufacturers have improved their quality enormously. ‘Through colour’ technology and much better finishes often make it difficult to differentiate between a clay tile roof and a concrete tile roof.
So it often comes down to other issues like budget, concrete is cheaper than clay, or planning and listed building consent where a traditional material may be required.
When it comes to deciding what slates or tiles to choose for your roofing project, you have to consider many different aspects of the project, from roof pitches, weight load, aesthetic design elements and many more. If you need help in considering these factors Maguire Brothers can provide you with an array of independent, unbiased roof reports and surveys.
If you have any questions in relations to the suitability of your desired roofing system, do not hesitate to get in touch with the team here.