Since man first left the caves, roofs were one of the first structures installed, as even in primitive times humans knew they needed to be protected from the harsh elements – whether that be sun, rain, wind, or snow. Believe it or not, archaeologists on some of the earliest roofs found materials including animal parts, wood, and clay; generally, items that they found in their immediate environment were used to complete roofs. For example, animal hides as well as being used for clothing would be stretched across basic timber structures or tied to tress to prevent the elements getting to them. Another common option would have been stick structures to prevent the worst of the weather getting through.
Thatching and clay tiled roof became the norm after several hundred years, clay tiles (mainly plain and pan tiles) are still in common use today. Lots of heritage buildings have these materials on their roofs due to their longevity and resilience if installed correctly. It’s often the case that on a 100 or 200 year old roof, around 50% of the tiles can be reused. There are still companies in the UK today that manufacturer hand-made clay plain tiles, which we often use to complete listed building works.
Slate roofs have a long history in the UK, with Welsh slate being installed on many heritage roofs and terraced houses across the UK. Slate, as with plain tiles, is also a very long-lasting roof if installed professionally – many churches have slate roofs on them. Welsh slate remains the top slate in the roofing market, however it is very costly, and so Spanish slate is becoming more commonly used. Spanish slates come in a wide variety to offer choice in today’s market. In early times, roofs, verges and abutments were completed with cement to stop birds and the element getting in. Wealthier clients would also have lead installed, which is another extremely long lasting product, but also quite expensive.
It’s still the case today, and that has been proven over centuries, that slate, thatch and clay plain tile roofs are still some of the best quality roofs when installed by a professional. However in modern times, roofs have begun to change.
The introduction of concrete tiles to the market reduced cost. Mass produced, so a lot cheaper than clay tiles, but also labour times are greatly reduced. While these concrete tile roofs are a lot cheaper with a wide variety of shapes colours and sizes to choose from, the life expectancy is reduced from its slate and clay plain tile counterpart. That being said, cement valleys ridge lines and verges in recent years have been replaced with UPVC or GRP system, which are a lot more long lasting than a cement mix which greatly increases the length of time before maintenance is needed in these weak spots. They also look very aesthetically pleasing and most new builds now have very little cement works on the roof and a very modern roof look.
In recent times, slate cost has decreased – not only through Spanish import, but also with a new man-made fibre cement slate on the market – which further reduces cost, but still gives a long lasting roof. These were originally made with asbestos fibres in them but have since been removed. Slate roofs also have the option for UPVC verges, valleys, and dry ridge systems to require less maintenance work over the years.
All roofs must now have a breathable membrane installed prior to the slates or tiles going on. As we are making our homes more energy efficient, this lining plays an important part in preventing the roof from any condensation issues. The very first non-breathable felt membrane introduced caused a lot of issues. As people upgraded their insulation, roofs began to sweat and cause damp issues. In most cases it is a simple fix by installing some vent tiles to create an airflow in the roof space.
The roofing industry is constantly looking for new ways to develop more energy efficient roofs. Tesla is currently installing solar slates that look stunning, unlike the bulky solar panel people have on their roofs now. These solar panels also make repairs difficult and costly. The tesla slates are hoping to complete testing in 2021.
As you can see, the roofing industry has changed dramatically over the years to help make new roofs more affordable and energy-efficient, but it’s still the case some of the early methods are still the best and long-lasting, If you mix these long-lasting methods (slate and plain tile) with the advancement of cement-less roofs. You have a maintenance-free long-lasting roof.
In the case of heritage and listed buildings, 99% of the time it’s a like for like roof – in some cases we even have to carry out works without using a power tool for cutting etc, and have to use traditional cutting methods like tile nibblers. I really enjoy these projects – whilst they present their own challenges, it very rewarding knowing you completed a roof the same way it was completed 200-300 years ago.
When looking at any project on a listed building always use a skilled contract and liaise with heritage or planning officer.