Irene Wanjiku Talks About Roof Evolution

The author of this article is a roofing specialist most commonly known as ‘The Roofing Queen’ and Managing Director of Rexe Roofing Products Ltd. Learn more about her here.

Most architects I have interacted with, and discussed some aspects of roofing for their projects, would not shy off from expressing their frustrations dealing with clients whose preoccupation is the roof. Not just a roof, but a complex one with a series of pitches and ridges combined with dormers and roof windows with surfaces pitched at absurd angles and finished with all manner of materials with varying colours, all as the clients fight to beat their neighbours by having the most ‘unique’ house. For them, to achieve this uniqueness and beauty, the roof is critical.

For the 15 years that I have been in the roofing industry, helping architects and developers put good roofs over the houses they design and build, I have come to learn that how a roof looks is important. More important however is the understanding that a roof equals protection and survival. A roof protects the things we love and care about and it offers us safety and strength if properly built and installed.

Man has utilized various natural resources, technological methods and ways of application throughout history to create the roofing we have today. From wood, mud and straw, to tiling, shingles and beyond, one thing we have always taken for granted is the necessity of a properly functioning roof for survival since the dawn of time. Roofs help protect us every day of our lives but we rarely think about them unless they stop working properly.

The earliest known roofing was the wooly skin of a giant mammoth noted in Siberia 40,000 BC.

In 100 BC the Romans introduced slating and tiling and in 735 AD thatched roofs made their debut. 300 years would pass before wood shingles bowed and it wasn’t until the 12^th Century when things really got moving. Right about that time, King John of England decided that thatched and reed roofs of London were to be replaced with clay tiles. This was in an attempt to reduce spreading of fires. This declaration became some sort of a ‘law’.

We have come a long way since putting wooly mammoth over our heads and the roofing industry has changed a lot in the last 200 years. The idea remains the same today as it was then; a quality roof is safety and protection from the elements, it keeps us warm during cold weather and cool when it is hot outside.

How a roof is built is dependent upon a number of factors, key among them is the architectural concepts implemented in the building design. The building design concepts, especially with regards to the roofs, would be influenced by the purpose of the building, available roof building materials and technologies, and the local traditions of construction.

The basic shapes of a roof include flat, mono pitched, gabled, hipped, butterfly, arched and domed. There are many variations of the same types and the factors which influence the shapes of the roofs are climate of the area and materials available for the roof structure and finishes for the outer layer.

Currently in Kenya, roof typologies are stagnant. Most residential buildings have pitched roofs, some which could even be of organic shapes mostly due to the use of flexible materials like thatch or shingles. A few variants have made use of flat roofs, ostensibly to create usable terrace spaces at the roof level. The dominant roof typology for the commercial buildings is the flat roof.

Pitched roofs are usually two sided sloped, mostly with a gable on both ends. If the gables are replaced with pitched surfaces, creating a pyramidal shaped roof, this variation transforms into a heaped roof. In most cases, the pitch of both sides is the same although it is not unusual to see roofs pitched at different angles primarily for aesthetics.

Majority of the roofing projects we have worked on in Kenya have a traditional joinery support structure. Construction of the structure is carried out on site with the help of sawn timber. The joints of the timber are nailed together and at times reinforced with the use of hoop iron around some of the joints. Fabrication on site is preferable as it allows for flexibility especially in cases where accuracy and consistency in measurements maybe a problem.

In the recent past, light gauge steel made a debut into the industry as a possible replacement to timber. The uptake has been on the rise with developers using it mostly as a truss structure in place of the traditional timber trusses. Its popularity is rising due to the light weight of the steel allowing for quick construction without heavy tools and equipment.

Pitched roof is also aesthetically appealing effective in shedding water hence reducing water leakage during heavy rains. Most home owners have come to refer to a pitched roof as the crown of their home, as if done correctly it not only depicts order but beauty of the home and elegance as well.

In reality, there is no flat roof. This term is generally used to describe roofs with low pitches, below 10 degrees. Mostly used for commercial buildings where the form of the building is not dependent on a visible roof. Climates with low levels of rainfall and high temperatures are also dominated with flat roofs that provide a living space on the roof in the form of a terrace. Flat roofs tend fail in places with high levels of rainfall.

As you ink down the sketches for your next project, or as you reconsider what you are currently building, we shall be at hand to share ideas and insights on several aspects of roofing for projects. The roof is a broad area whose surface we have just touched. In the coming issues of BUILDesign Magazine, we shall delve deeper into the various aspects of roofing and engage with you as we discuss some of these aspects in detail.