What you need to know:
- Due to its many advantages, steel trussing is more expensive than that done with timber. However, Mr Mugo says this price difference is justified.
- Heavy-gauge steel is recommended for churches due to their large span while light-gauge steel is more suitable for residential buildings, which have a smaller span.
To mitigate the effects of fires on buildings, stakeholders in the property industry are seeking alternatives to wood, which has been the most commonly used material for trussing.
Mr Francis Gichuhi Kamau, an architect at A4 Architects, says that when a building catches fire, it normally spreads through the roof, which means the roofing material used is important.
“Apart from other precautionary measures such as using calcium-silicate ceilings for commercial kitchens, using steel trusses is a splendid move,” says Mr Kamau. “One can use either light- or heavy-gauge steel trusses, depending on the building’s span.”
For instance, heavy-gauge steel is recommended for churches due to their large span while light-gauge steel is more suitable for residential buildings, which have a smaller span.
“We are trying to conserve our environment by discouraging the use of timber for trussing; it means no cutting down of trees. Then, in terms of durability, steel trusses reign supreme. We recommend the use of steel for trussing, but we advocate more for the light-gauge because the heavy-gauge is normally painted, and the paint catalyses the spread of fire in case of an outbreak,” says Mr Charles Mugo, a project sales engineer with Safal Building Systems Ltd, which specialises in the design, manufacture and supply of pre-engineered steel trusses.
“Apart from being fire-resistant, steel trusses have other notable advantages: they offer design flexibility, are easy to assemble and erect on site, are termite resistant and also environment-friendly since they are recyclable, meaning there is no wastage.
Besides, using galvanized steel, (which is coated with other metals like zinc) ensures durability since it is rust-proof,” adds Mr Mugo.
Due to its many advantages, steel trussing is more expensive than that done with timber. However, Mr Mugo says this price difference is justified: “The advantages of steel trusses far outweigh those of timber, which is susceptible to termites and fire, and can even rot after some time, especially in areas with heavy rainfall.”
For steel trussing to be effective, its installation greatly matters, he says. First, if the spacing is not properly done, problems might arise.
“But this can be avoided by using design softwares such as Mi-tech 2020, which ensures accuracy in the design,” he says. Second, the work should be done by qualified people.
Third is choosing the better option. Instead of using painted steel, go for the galvanized option, which is rust-proof. In addition, buy products under warranty to cushion yourself against defects. advises Mr Mugo.
Steel trussing can be used in all types of buildings, including residential houses, institutions such as schools as well as commercial and industrial buildings.