In the debate on steel vs timber frames, there are many misconceptions and myths that confuse home builders. It is important to understand the options available and the implications that your choice can have on future costs and circumstances for your home, when deciding to use either steel or timber trusses.
It is fair to suggest that timber is fast becoming the old fashioned way to build. It allows construction errors to be rectified on-site with a hammer and nail – which is cheap and easy for the builder but not very reassuring for the homeowner. Timber also contains natural weaknesses and is susceptible to damage.
Timber is a natural cellulose material and is milled with all its natural imperfections and inherent weaknesses. Timber frames are susceptible to damage in both termite infestation and internal surface stress fractures, the costs of which can be substantial. In comparison, steel frames and trusses, are engineered to be stronger, more secure, and most importantly, termite proof.
Wooden trusses are generally cheaper than steel trusses, however they don’t last as long. Because timber is a natural material, it cannot stand up to the elements as well as steel. Timber trusses may warp and bow over time, which can cause structural damage to the rest of the building. Wood is also susceptible to rot and insect infestations, which may call for costly repairs. Timber trusses are also more likely than steel to be damaged in wild weather conditions. Despite these risks, many opt for timber frames because they seem more economical.
Steel roof trusses are usually more expensive than wooden trusses, but you can expect them to last a lot longer. Chemical treatments aren’t needed to maintain the frame and insect infestations aren’t a risk. They are also lightweight, making them easier and quicker to transport and install. What’s more, steel frames can be recycled easily, so steel is a good choice for the environmentally conscious home or business owner. Although steel frame roof trusses require more skill to install, an experienced team should be able to fit your steel trusses quickly and efficiently.
Steel trusses maintenance costs are lower compared to timber. Timber will required seasonal treatment against termites while steel trusses can last more than 20yrs without having to worry about the structure.
In Kenya, several companies including TechnoConstruct Kenya Ltd are providing light gauge steel trusses and roofing solutions. Because of this, the cost of timber vs steel trusses is within 10% on either scale. This means, depending on your roof, the cost of steel roofing compared to timber will either be lower or higher but cannot exceed 10% of the cost of timber roofing.
In many instances, the roof profile affects the design and materials used on a project. A complex roof profile or a steep roof (say 30 degrees and above) will result to a lot more materials than simple roof profiles or less pitched roof designs. It would be great to discuss with your architect on your choice of material during design.
While it might seem cheaper to get a timber roofing at the onset, in the long run, you will save a lot more going for steel trusses.