There are many and varied products that can go on your roof. If your building requires planning permission then the planners may well want something that is in keeping with the immediate or surrounding area. All the tile and slate options will be available in new and second hand.
Tiles come in a choice of Clay or Concrete. Concrete tiles are usually cheaper but they tend to lose their colour over time while clay is a natural and sustainable roofing material which is strong and has a rich colour that never fades. If you would like to know more about clay tiles then you can visit the Clay Roof Tile Council here
Most plain tiles today are 265mm long x 165mm wide, a fixed size was introduced in the reign of Edward IV in 1477/8 to make sure manufacturers did not skimp on size so they could make more money.
Plain tiles can be split into machine made tiles and handmade tiles.
Machine Made tiles
Machine made clay tiles are the cheaper of the two options and give a very uniform finish to the roof. There are a lot of manufacturers and most machine made plain clay tiles will be suitable down to a roof pitch of 35° and up to a vertical 90°. Marley Eternit also have an Acme Single Camber Clay Plain Tile that will go down to 30°.
Handmade tiles provide slight random irregularities which give the roof as bit more character than machine made tiles. The minimum roof pitch this type of tile can go on varies by manufacturer. Some can go down to 35⁰ and others can only go down to 40⁰.
Interlocking tiles give the external look of plain tiles but are designed to be able to go down to a minimum roof pitch of 22.5⁰.
The peg tile gets its name from the method of fixing the tiles to the battens with small round wooden pegs driven through square holes which are punched into the tile at the moulding stage. Some peg tiles can also be smaller than a standard plain tile at 250mm x 150mm but there are differences between manufacturers and some secondhand peg tiles are even smaller.
Pantiles are large roof tiles, S-shaped in section. They are side lapping and the ends only overlap the course immediately below unlike plain tiles which lap two courses. There are many different pantiles and the minimum roof pitch of them ranges from 22.5⁰ to 30⁰ so you need to check you are getting the right ones if you are on a shallow pitch. Also note that the headlap for the tiles is greater the lower the pitch which means you will need more tiles per m² for the lowest roof pitches.
Slate is a good roofing material because it has an extremely low water absorption index of less than 0.4%. this low tendency to absorb water also makes it very resistant to frost damage an breakage due to freezing. If properly installed a slate roof will provide a long-lasting weathertight roof with a typical lifespan of around 80-100 years.
Slates come in a number of standard sizes when traditionally produced. These names include Countesses, Duchesses, Princesses, Narrow Countesses, Wide Ladies, Broad Ladies, 14×10’s and Drains. There are many different kinds of slate in different thicknesses and textures.
The minimum roof pitch and the size of tile you will need for your roof depends on how exposed your site is. On moderately exposed sites then you could get to a minimum roof pitch of 20⁰ by using a 600mm x 350mm slate with a 115mm head lap. if you are on a site of severe exposure then the minimum roof pitch would be 22.5⁰ with the same size slate and a head lap of 130mm.
There are fibre cement slates on the market and these are considerably cheaper than natural slate but lack the long lifespan and character of natural slate.
Natural stone has been used on roofs in the north of England and Scotland for hundreds of years due partly to the harsh weather conditions and also the availability of suitable local stone.
Natural stone slates are usually laid in diminishing courses with the bigger slates at the bottom and the courses reduce in size as you go up. The sizes can range from 1100mm high down to 350mm high. If you give the supplier a copy of your roof plan they will work out how many of each size you need and then give you a batten layout to suit.
SHINGLES / SHAKES
Wood shakes and shingles are manufactured from western red cedar, cypress, pine and redwood trees. Shakes are split from logs and then reshaped and are usually thicker at the butt end as compared with shingles. Shingles are sawn both sides and have an even taper and uniform thickness. Both shakes and shingles are available pressure treated but only Western Red Cedar products are available with a fire-proof pressurised treatment.
The minimum roof pitch for shingles is 14⁰ and for shakes is 20⁰. The lower the pitch the greater the lap needs to be and the more shingles/shakes you need per m². The lifespan for treated shingles and shakes is about 40 years.
A thatched roof is where reed or straw is laid on the roof in quite a thick layer and the idea is that the water runs off the material. The life span of a thatched roof depends on the material used, the exposure of the roof to the elements and the roof pitch. The higher the roof pitch the longer the life span as the water runs off better and does not penetrate into the thatch so much.
On average Water Reed should last 40-60 years, Wheat Reed 25-40 years, Long Straw 20-35 years and you will be looking at a new ridge every 10-15 years.
There are many different types of profiled sheet including corrugated, box profile, GRP, Fibre Cement and tile effect sheets. Some of these sheets can go down to a minimum roof pitch of 5⁰.
Lead is the metal most commonly associated with roofing being used both as a roof covering and a flashing material.
Lots of useful information about Lead can be found here at The Lead Sheet Association website.
Copper has been used as a roofing material since ancient times and is recognised by the greenish roofs and domes you see today. The colour comes from the reaction of air with copper which creates an additional protection against corrosion which is called verdigris or patina. Since the copper comes in sheets up to a thickness of 1mm you will need a boarded surface for it to go on. Copper roofs have been known to last over 700 years and it is usually the boarding that fails first.
More information about Copper can be found at the Copper Development Association website.
Zinc is being used more now in the UK and has an excellent visual appearance and long life. It requires minimal maintenance and is cost-effective and versatile. Zinc roofs should last up to 40 years but some have lasted well over 100 years.
A green roof is designed to allow vegetative growth and can also be called a living roof, biodiverse roof, Sedum roof to name but a few. There are 3 broad classifications which are Extensive, Biodiverse and Intensive.
This is where the roof provides an ecological protection layer to extend the membranes life and create a wildlife habitat. You can have a colourful carpet of planting including hardy succulents, herbs and grasses. The build-up height is up to 120mm and requires minimal maintenance and usually no watering.
Diverse plant strategies that can be tailor made to attract specific wildlife. Can be non-vegetated or planted with native hardy succulents, grasses, herbs and wildflowers. The build-up height is up to 200mm and requires minimal maintenance and no watering.
This is where the roof can be used as domestic garden and planted with lawn, bushes, shrubs and small trees. You can also combine with hard landscaping and water features. The build-up height can be up to 1500mm and it will require regular maintenance and watering.
Each project is different and a specific solution should be designed for your building by a specialist contractor.