How Environmentally Friendly Is Your Roof Covering?
In the face of the new climate change report published by the Intergovernmental Panel on Climate Change (IPCC), and mindful of our mission to promote the environmental benefits of solar energy, we want to make sure that our roofing services are in line with our mission to reduce carbon emissions.
There are a number of factors that can determine the environmental impact of your roof. It is important to look at all stages of the product lifecycle from manufacture, transportation, coverage, replacement, recyclability, insulation.
Evaluating the Environmental Impact of Your Roof Covering
- Embodied energy - Embodied energy is the energy consumed by all of the processes from the mining and processing of natural resources to manufacturing, transport and product delivery. The main energy expenditure is from manufacturing and transportation. As with other materials, sourcing a product in the UK (and close to site if possible) can dramatically reduce its embodied energy.
- Durability - The lifespan of your roof tiles is an important factor to consider when looking at their environmental impact. One roof tile may use more energy to produce than another, however if it lasts twice as long the overall emissions may be less than the other. Generally, the longer your roof tiles last, the lower the overall environmental impact.
- Material efficiency - The energy efficiency and insulation of roofs can determine the amount of energy that you consume.
- Reusability - Can the tiles be reused, recycled? or do they get sent to landfill? Construction waste is a growing issue and more and more companies are aiming for totally recycled, zero-landfill waste.
The Environmental Impact of Your Roof Covering
We have been busy tracking down the most environmentally friendly roof tiles for your houses. So here's our analysis on the tile candidates:
Clay Roof Tiles
Clay roof tiles are the most traditional roofing material and have been used on roofs for centuries. They are a popular choice among homeowners due to their attractive and natural Mediterranean aesthetic. Whilst the most usual colouring is the natural clay colour, the tiles can come in a variety of colours. Until recently, clay was a significantly more expensive option than concrete however, advances in technology now provide more cost effective clay solutions.
How Clay Roof Tiles Are Made
- Raw materials - Clay is a natural resource taken from quarries.
- Preparation - The clay is then crushed to attain the required grain size. If necessary, water or sawdust can be added to make sure the clay is of the right consistency.
- Shaping - Once the clay has the right consistency, it is moulded into shape and cut to the desired size.
- Drying and firing - The shaped clay products are first dried to reduce their moisture content and then are loaded into kilns for firing. The high temperature in the firing process gives clay roof tiles their long life-span and durability
The Environmental Impact of Clay Roof Tiles
Clay is an abundant natural resource and is often considered one of the more environmentally friendly tiles. The tiles are durable and have a long life expectancy of around 50-70 years. Although many Mediterranean tiles have lasted for centuries.
While this is a natural and long-lasting resource, the firing process is an energy-intensive process which contributes to large CO2 emissions. Quarrying can also have major impact on landscapes and local ecosystems.
|✔️ Reusable||❌ Clay extraction can degrade landscapes|
|✔️ Durable||❌ High embodied energy|
|✔️ Large reserves||❌ CO2 emissions relating to the firing process|
Concrete Roof Tiles
Concrete is a popular roofing material due to its versatility. It comes in many different shapes, colours and designs and can mimic the aesthetic of clay and slate. This low cost option offers a range of roofing solutions for the homeowner.
How Concrete Roof Tiles Are Made
- Raw materials - Concrete roof tiles are made of a mixture of aggregate (rock, sand or gravel), cement and water. Cement is made through blasting rocks with explosives. These rocks are then ground to a powder.
- Preparation - These resources are carefully proportioned and mixed. Typically a mix is about 10-15% cement, 60-75% aggregate and 15-20% water.
- Moulding - mixture is pressed into a mould for the desired shape.
- Firing - The moulded tiles are then sent to a kiln to be fired. This hardens the tile and makes it stronger.
The Environmental Impact of Concrete Roof Tiles
Concrete tiles are one of the cheaper roofing options and offer versatility in appearance. The process of producing the tiles however, releases high levels of CO2 and other emissions. 4-5% of the total global CO2 emissions are caused by cement production. The process of extracting the aggregate can degrade landscapes and impact local ecosystems.
|✔️ Reusable||❌ Very high levels of CO2 and other emissions associated with cement production|
|✔️ Durable||❌ Aggregate extraction can degrade landscapes|
|✔️ Some products use recycled aggregate||❌ Concrete can contain a range of admixtures, the impacts of which have not yet been sufficiently assessed|
|✔️Some products use cement substitutes||❌ Issues concerning quality assurance|
Coming in at a slightly more premium price, slate tiles offer an elegant stone aesthetic. The tiles have a naturally cleft surface and offer a classy appearance to your rooftop. Most slates originate from mines in Wales, Canada, Brazil, Spain, and China. Welsh slate is the most expensive, however the environmental impact of transportation is significantly lower than importing the slate from the other regions.
How Slate Roof Tiles Are Made
- Raw materials - Slate is a natural stone extracted from mines. The extraction process can damage the slate so it needs to be done carefully.
- Slab cutting - After excavation, the slabs are cut into more manageable sized pieces
- Splitting - Slabs are split down to a specific thickness. Again this must be done carefully as if tiles are split in the wrong area, the tile can break
- Trimming - Here the slabs are cut into a tile shape.
- Grading - The tiles are finally divided into different categories based on their colour and thickness.
The Environmental Impact of Slate Roof Tiles
Slate is a natural resource and the manufacturing process has very little CO2 emissions. The material is durable and reusable often lasting 75-100 years, however this can be reflected in the more premium price.
Due to the extraction process and natural properties of the stone, there is often a high level of waste in production.
|✔️ Reusable and recyclable||❌ High embodied energy if imported|
|✔️ Low embodied energy if sourced in the UK||❌ Accessible reserves are relatively low in the UK|
|✔️ Very durable||❌ Slate quarrying can degrade landscapes|
|❌ High level of waste generated during production|
Fibre Cement Slates
Fibre cement slates are a light weight roofing solution and work well on buildings where weight is a more important factor, such as conservatories. This material is versatile and can come in a range of colours.
How Fibre Cement Slates Are Made
- Raw materials - Fibre cement is formulated with a mix of cement, silica and fillers together with a blend of cellulose and synthetic fibres. Cement is ground up rocks, sand and gravel.
- Mixing - The cement powder is mixed with water and fibres. Wood pulp is added to give the material a bending strength.
- Shaping - After mixing, the material is rolled out and cut into slabs
- Steaming - Pressurised steam is used to cure the products. The slabs are steamed at 170°C for around 9 hours
- Trimming - The slabs are then cut into a tile shape
The Environmental Impact of Fibre Cement Slates
While this synthetic material offers a low cost and lightweight roofing solution, it is not great for the environment. The energy intensive process of creating concrete and the emissions released through creating the synthetic polymer fibre make the material one of the most polluting roofing materials.
|✔️ Reusable||❌ Very high levels of CO2 and other emissions associated with cement production|
|✔️ Durable||❌ High levels of material extraction for cement|
|✔️ Light weight reduces roof loading||❌ Synthetic polymer fibre is derived from oil, a non-renewable resource, the refining of which is responsible for sulphur dioxide and nitrous oxide emissions|
|❌ Manufacturing of plastic polymers is energy intensive|
|❌ Synthetic polymers will not biodegrade and are non-recyclable|
Reclaimed Roof Tiles
Why not find recycled tiles to put onto your roof? Whether you want clay, slate or concrete tiles, by recycling the tiles you will be able to reduce your environmental impact.
The Environmental Impact of Reclaimed Roof Tiles
If you use recycled roof tiles, the only environmental impact you may consider will be transportation of the tiles. This is the most environmental option however there are much more concerns around quality and appearance.
You can't always rely on there being enough tiles for your roof!
|✔️ Reusable||❌ Issues concerning quality assurance|
|✔️ Down-cyclable||❌ Can't always rely on right quantity|
|✔️ Negligible embodied energy if sourced locally|
|✔️ Diverts demolition waste from landfill|
|✔️ No toxic emissions from a manufacturing process|
Timber Shingles and Shakes
One of the most natural aesthetics for your roof can be achieved through timber roofing. While the life cycle of these roofs is much lower than others, it can be a popular choice among homeowners.
How Timber Shingles and Shakes Are Made
- Raw materials - Shingles and shakes are made from wood.
- Log handling - Trees are cut down and cut into appropriate length logs.
- Cutting - The wood must be cut precisely perpendicular to the grain to maintain product quality
- Manufacture - Shake blocks are split into thick slats using a hydraulic press with an attached blade. These make sure all the slats are the same size.
The Environmental Impact of Timber Shingles and Shakes
As seen above, this process involves cutting down trees which can be detrimental to the environment. Despite this, many companies re-plant trees to ensure that the method is sustainable.
The material has a life expectancy of around 30-50 years and is more flammable in the case of a fire, so doesn't last as long as some of the other roofing materials.
|✔️ Reusable and recyclable||❌ Cedar shingles are usually treated with preservative|
|✔️ Very low embodied energy if sourced in the UK||❌ High embodied energy associated with importation|
|✔️ Renewable resource but be sure to use FSC sources||❌ Maintenance issues|
|✔️ Can be re-used though there are no facilities for recycling||❌ Concerns over fire|
|✔️ Sequestered CO2|
|✔️ Production can make use of otherwise unusable logs or parts of logs|
|✔️ Light weight reduces roof loading|
Rubber Roof Tiles
Rubber roofing is perhaps one of the cheapest roofing materials and is made from recycled tyres, sawdust and slate dust.
How Rubber Roof Tiles Are Made
- Materials - Rubber roofing is made from recycled tyres, sawdust and slate dust.
- Preparing the rubber - The tyre gets cut into large pieces and coated in slate dust and sawdust
- Moulding - the pieces are heated and moulded under high pressure adding more slate dust and sawdust to create texture.
The Environmental Impact of Rubber Roof Tiles
This fairly modern roof tile can be up to 100% recycled content making it a great environmentally-friendly roofing option.
|✔️ Up to 100% recycled content||❌ Sometimes only sporadically available|
|✔️ Reusable and recyclable||❌ Manufacturers tend to go in and out of business|
|✔️ Light weight reduces roof loading||❌ Relatively untested|