Timber or steel: which is better roofing option?

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Building a house is one of life’s most monumental achievements. While the roof is typically one of the final phases in construction, experts stress that its importance goes beyond merely proving shelter.

According to Fred Lukoda, a construction expert, the design of the roof significantly impacts the overall appearance and durability of a house.

“The structural design of the roof plays a crucial role in how your home looks,” Lukoda explains.

“Beyond appearance, the quality of the roofing materials and their final touch, including colour and style, determine the long-term aesthetic and durability of your home.”

Choosing the right roofing structure

David Kireli, a civil engineer, emphasises that your choice of roofing material should be in line with the architectural design of your house. He notes that heavier roof structures, for instance, cannot be supported by weak foundations.

“Many people overlook the importance of matching the strength of the house’s lower structure with the roof. Heavy roofs need strong foundations; otherwise, the entire structure could be at risk of collapse,” Kireli says.

Timber roof structures

Peter Wasswa, another construction expert, notes that roof structures are the backbone of a roof’s appearance and function. Typically, roof structures are made from long, rigid materials like timber or steel. However, the choice between these two depends on availability, durability, and cost.

For timber roofing, hard woods such as eucalyptus, mvule, mahogany, cyprus, or pine are often used due to their strength and durability. But, as Wasswa points out, the price of hardwood timber has soared in recent years due to deforestation and scarcity.

“Timber comes in various sizes, such as 6x2 inches, 4x2 inches, and 3x2 inches, each serving a different purpose in the roofing structure,” Wasswa says.

Denis Kimuli, a timber dealer, adds that the cost of timber depends on its type and size. For example, a 14-foot, 6x2-inch piece of mahogany wood can cost between sh45,000 and sh50,000. More affordable options include eucalyptus, Cyprus, and pine, with prices ranging from sh19,500 to sh42,000 depending on the wood. Timber offers several advantages: it's lighter than steel, requires less labour, and does not need electricity on-site for installation.

However, timber must be treated with preservatives to prevent pest infestations, which adds to the cost.

Steel roof structures

A house being roofed with steel. (Courtesy)

As hardwood timber becomes scarcer, many homeowners are turning to steel for roofing structures. Steel girders, which serve as the horizontal support beams for smaller steel beams, provide a durable alternative.

Fred Mpalanyi, a carpenter, explains that steel roof structures are more resistant to pests like beetles and do not require the preservative treatments timber needs. This makes steel a long-lasting, low-maintenance option.

“Steel does not need maintenance, unless there is a leak,” Mpalanyi says.

However, steel roofing requires more labour, and electricity is needed on-site for welding the girders in place.

Additionally, the weight of steel structures may be a disadvantage in certain cases, requiring a stronger foundation than timber roofs. Despite these drawbacks, Mpalanyi concludes that, steel is often a more cost-effective choice over the long term due to its durability and minimal maintenance requirements.

To learn more about these and many other construction insights, please visit the Homes and Construction Expo, 2024 set to take place at Lugogo Show Grounds on November 30 and December 1.

The event will feature educational workshops, seminars, and panel discussions focused on emerging trends, industry challenges, regulatory changes, and topics of interest to real estate developers and construction professionals.