Design & Interiors

Easy-to-build city houses

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Carol Wanjau, homeowner, poses outside her 2 40 foot container prefabricated house in Karen on March 5, 2021. PHOTO | DIANA NGILA | NMG

Summary

  • Many Kenyans are looking for homes that are much easier to build, and far cheaper too.
  • This has pushed up demand for prefabricated structures that are easy to erect.

When Carol Wanjau’s house was being constructed, the workers started with fixing two 24-feet containers on her land, supported by steel stilts. It did not look like a normal house. But in three months, it turned out to be a beautiful, relatively cheaper four-bedroom house.

Many Kenyans are looking for homes that are much easier to build, and far cheaper too. This has pushed up demand for prefabricated structures that are easy to erect.

In Nairobi’s Karen, Mrs Wanjau’s two-storey home stands elegant. The mustard yellow walls, brilliant white ceiling, timber-like vinyl floor, make it warm and inviting.

From the outside, one can assume that it has been constructed using traditional brick and mortar. Except it was not. Her house was built using steel and cement materials, and grounded on two 24-feet containers, an innovative way of building homes referred to as steel panel technology.

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Carol Wanjau's 2 40 foot container prefabricated house in Karen on March 5, 2021. PHOTO | DIANA NGILA | NMG

Together with her husband, they had always wanted to build their own home but Covid-19 fast-tracked the process.

“We found ourselves vulnerable, without the security of having our own home,” she says. They chose the steel technology because it was affordable, fast and environmentally-friendly.

Having interacted with the technology five years earlier in a classroom construction project at her church, the decision was a “no-brainer as the classrooms were stable, with no structural issues having withstood the test of time, weather and human scrutiny.”

“We broke ground in November 2020 and by the end of January 2021, we had already moved in,” Mrs Wanjau who is also a counsellor says.

The house cost about Sh6 million.

Edward Mugo, an architect and the director of Modular Group, a firm that specialises in steel panel homes says this technology cuts construction time by 70 percent.

He says a standard three-bedroom bungalow, which normally takes eight to 14 months to complete, is done in three months.

Mr Mugo who founded the company in 2019, says the technology is gaining traction and he has built steel panel homes not only in Nairobi’s Karen, Kangemi, and Tassia estates, but as far as Oloitoktok.

“Materials used are steel (columns, beams, and panels), concrete, and plaster. The result is a building that can last for years,” says the architect who has been in the industry for 27 years.

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Carol Wanjau's 2 40 foot container prefabricated house in Karen. PHOTO | DIANA NGILA | NMG

Born into a family of a steel fabricator father, Mr Mugo has been welding since childhood and believes in the strength and longevity of steel.

The steel columns and beams make the shell which provides support. The steel panels, concrete, and plaster are then used to make the walls. The steel-framed structure is constructed offsite and then welded together on site.

This technology, he says, lowers construction costs by 25 percent. One gets to save at excavating the foundation, materials used, and labour. For instance, Mr Mugo says, building a 160 square metre by 200 square metre home using traditional building materials costs Sh52,000 per square meter, while using steel costs Sh40,000 per square metre and Sh32,000 per square metre for high-end and standard finishes respectively.

“The steel columns are sunk at least one meter into the ground, therefore, removing the need of a deep foundation which is costly. Replacing stone with concrete and plaster is also a money saver. Stone is becoming scarce. A good quality building stone costs between Sh80 and Sh100. And the price will only go up in coming years,” he says.

Once the house is complete, a homeowner can use ceramic tiles for floors and kitchen counters; gypsum boards for ceilings; MDF boards for cupboards and wardrobes, and roofing, one can use box-profile pre-painted corrugated iron sheets.

For high-end finishes, timber-look vinyl strips are used on the floors, gypsum boards on the ceiling, granite for kitchen counters; MDF boards with laminate finishes for cupboards and wardrobes, and for roofing, Decra or concrete or clay tiles.

Although Kenyans would see the steel-frame designs as too radical a departure from traditional concrete homes, Modular Group says the offices, shops, schools and lease rentals they have built is proof that the technology works.

What to consider

To build using this technology, a homeowner must know the size of the house beforehand as this is important in costing. Mr Mugo advises clients to build a two-storey since, beyond this, it stops becoming economical as the cost of steel increases significantly.

“Other factors to consider are the availability of electricity. It must be regular electricity since we use it to weld the structure together,” he explains, adding that the location of the home is also considered for logistical planning which adds on to the cost and the time required for completion.

But how sturdy are the steel-panel home and is the insulation adequate?

“Steel buildings can last as long as stone ones and they are even of higher quality. They can also be put up on any type of soil—black cotton or red. As for insulation, we put about five inches of concrete and plaster on the wall, making it function just like stone,” says Mr Mugo.

Having lived in stone-built houses as well, Mrs Wanjau says that the experience is the same function-wise.

“Our house came out just as we had designed and envisioned. The bathroom, toilet and kitchen function perfectly,” she says, adding that “It’s also not hot as people assume and neither does it creak when we walk up and down the stairs.”

Mr Mugo’s goal? “To put up a four-bedroom house in just two weeks,” he says.