Is your home weather-resistant? Factors to bear in mind

The goal of every building is to ensure that the user’s productivity in that space is at optimum level. PHOTO | SHUTTERSTOCK

What you need to know:

  • Most Kenyans opt to bypass professional input, often citing cost, only for that decision to prove expensive later.
  • And the problem is not only entrenched in the residential sector, it is almost the norm in the commercial sector.

  • This, coupled with poor workmanship, has often been blamed for the collapse of buildings in Nairobi and across the country.

When Ms Mary Njeri, a civil servant in Nairobi, moved into her new house at Juja Farm estate on Thika Road in March last year, she was ecstatic.

“I couldn’t believe I was moving into my new three-bedroom house surrounded by a perimeter fence and my own compound with space for a kitchen garden. To say that I was happy would be a huge understatement,” the mother of two says.

BASIC DESIGN

Hers was the culmination of more than 10 years of sacrifice and meticulous saving. Her dream of one day owning a roof over her head and saying goodbye to landlords and their pesky agents had finally come true.

But no sooner had she started to enjoy the comfort of her new house than trouble began. To begin with, the large windows she had asked the contractor to instal so that she could get a view of Mt Kilimambogo in the distance would turn out to be the greatest source of discomfort.

She says, “The house would be too hot on a sunny day because the windows would let in a lot of direct sunlight into the house, turning it into a 'sauna'.”

To find out what she could do about this problem, Ms Njeri turned to the internet, and after some investigation, she found out that the builder had made a grave mistake at the onset of construction. When designing a house, one of the factors architects must take into account is the orientation of the building. For people living in the tropics, it is recommended that the house be built on the east-west axis, with windows facing the north-south direction, which keeps the house away from the sun’s path.

It turned out that the contractor Ms Njeri had employed did not adhere to this basic house design principle since the windows were facing the east-west direction, and the contractor had not installed any sun-shading devices.

THERMAL MASS

But that was not all. The walls’ ability to absorb heat, known as thermal mass, was also questionable. If constructed to the approved standards, walls with high thermal mass should absorb the excess heat during the day and release the “stored” heat at night, therefore naturally regulating the house’s temperature. This was not the case with Ms Njeri’s house.

Additionally, in the course of her research, she says, she found out that the builder should have gone for high interior ceilings as opposed to low hanging ceilings, going by the surrounding environment. High ceilings provide space for heat to rise and be wasted.

Ms Njeri lays the blame for her predicaments squarely on the developer, but her complaints have fallen on deaf ears. For now, what was meant to be a safe haven and a comfort zone has been the complete opposite.

“I have had to hire an architect to study the house and see how the mistakes can be rectified. That comes at an extra cost to me,” she says.

“In a span of one year, this house has taught me a lot about basic design techniques that I think every person who aspires to become a homeowner should be aware of before taking the first step.”

LARGELY IGNORED

Like Ms Njeri, when building their homes, most Kenyans opt to bypass professional input, often citing cost, only for that decision to prove expensive later. And the problem is not only entrenched in the residential sector, it is almost the norm in the commercial sector. This, coupled with poor workmanship, has often been blamed for the collapse of buildings in Nairobi and across the country.

Indeed, according to a recent survey by the Architectural Association of Kenya, only two in 10 (20 percent) buildings in Nairobi are developed by architects. Other professionals who are crucial in the construction process but are largely ignored include engineers (either structural, mechanical or electrical), quantity surveyors and interior designers.

While Ms Njeri’s case speaks volumes about the need to have a competent team on site, it is also a clear indication that homeowners need to be aware of what to expect at the end of the process, whether or not they will personally supervise the project.

So, what are some of these basic principles and how can you ensure your house withstands different weather conditions without causing you and your family discomfort?

NUMEROUS BENEFITS

DN2 spoke to Mr Kevin Oduor, principal architect and CEO of Do Design Consultants (DDC Architects), and Mr John Kabuye, an architect and vice-chairperson of the Kenya Green Building Society, in an effort to find answers to these questions.

At such a time when climate change is a hot topic across the world, understandably so because of the adverse effects being felt especially within the tropics, the two architects, who are great proponents of green building, did not mince their word underlining the importance of homeowners going green.

“Green homes, otherwise known as resilient or sustainable homes, are homes that can lessen the environmental effect, help to make the space comfortable and healthy for the occupants. A homeowner will enjoy numerous benefits such as good health, low utility cost, comfort and resilience because he will not be entirely dependent on external systems to live well,” said Mr Kabuye.

Says Mr Oduor, “Architecture is not about grand and iconic structures that are good to look at, it is about developing a usable, workable space with high human comfort levels that will allow you to be as productive as possible and provide you with an economically sound, socially acceptable and ecologically sustainable development.”

EAST-WEST AXIS

To avoid finding themselves in the situation Ms Njeri finds herself in currently, Mr Oduor says the way forward for current and prospective homeowners is to look at development through the prisms of design principles of building within the tropics.

Issues such as house orientation, walls’ thermal mass, waste management, use of local materials and water harvesting should take centre stage, Mr Kabuye points out.

“Is the orientation on the east-west axis? Are the windows facing north-south away from the sun’s path? Is the plan narrow to allow for cross ventilation? Do the walls have a high thermal mass for absorption and dissipation of heat at the required time? Do the windows have sun-shading devices to prevent direct sunlight into the space? Are you harvesting rain water? Are there proper waste management practises? Is the building bright-coloured to reflect heat? (Silver and white are good reflectors) Are the building materials of low-embodied energy? (This has to do with the amount of energy used to produce and transport materials to the site). Are you using locally available materials?” These are just some the issues the design principles addresses.

Here are some of the issues that one needs to bear in mind to ensure their homes can withstand every climatic condition. Understand the surrounding environmental conditions.

ENVIRONMENT

The first step towards climate-proofing a home, Mr Oduor advises, is to find out as much background information about the surrounding environment as possible.

“For any given development, two things influence the outcome: environmental conditions of the site and the client’s brief. Whenever architects set out to do some work, one of the most important things they do is to weigh the site forces vis-à-vis the brief.”

He adds that when it comes to making a decision concerning the two sets of considerations, a prudent architect will tend to favour the site’s environmental conditions over the brief given by the client. Set within the tropics, Kenya has a temperature disparity of between 14°C and 32°C for the harshest areas. Other than that, the country has about five main climatic conditions. Some of them include modified equatorial coastal climate (Coast region), modified equatorial lake region climate (Kisumu and its environs and Lake Turkana region), modified tropical highland climate (central region, Nairobi partly), and desert and semi-desert climate.

ACOUSTICS

“That in itself provides an architect or somebody who wants to build an idea of where to start. With each condition, you will find that the temperatures are different. For example, in Nairobi, the annual range is between 24°C and 28°C with rainfall of about 800mm per year. This varies with other regions, say the Coastal region, where temperature is a bit high and the amount of rainfall and humidity are also higher,” Mr Oduor says, adding that what you would want to have as a solution in Nairobi might not necessarily be a good housing solution in Mombasa.

“When you look at all these climatic conditions, they tell you that buildings are supposed to be built differently, depending on where construction will take place,” chips in Mr Kabuye.

“When we are building with climate in mind, you therefore have to make sure that you employ the right initiatives or interventions,” he adds.

Having worked on developments in Nairobi, Mombasa and the lake region, the architect observes that the biggest factor one has to grapple with is how to cater for comfort. The three things that come into play when designing for comfort are thermal dynamics, daylight range and acoustics.

ENERGY COST

Can you sit in your living room for 24 hours without necessarily having to wear a jacket or having to buy a fan or air conditioner to try and adjust the temperature in the house? If your answer to this question is yes, Mr Oduor says, then your house meets the fundamental thermal comfort required of a home or building.

The goal of every building is to ensure that the user’s productivity in that space is at optimum level. Here, there are a number of issues that can help you determine whether the house serves you right.

“Do I have to use a torch to move around? Do I have to move closer to the window to work conductively in the house? Is my peace disrupted by the passing vehicles on the road that is adjacent to my house? From a user’s point of view, the answers to these questions define a building that was built right, or one that failed to meet required standards.

It goes without saying that the cost of energy in Kenya is high. With this in mind, your goal should be to spend as little energy as possible to run your home.

If you have to switch on the lights in your home a couple of hours before dusk, or you have to use electricity to heat water, then your house is not energy-efficient, says the architect.

'SICK HOUSES'

While Ms Njeri counts herself lucky that the conditions in her house did not get to the point of undermining her health, Mr Kabuye, a consultant architect, points out that poorly designed buildings that do not meet certain standards can cause illness. Referred to as “sick building syndrome”, this is a situation in which occupants experience effects such as headaches and breathing problems, and which appear to be linked to the time spent in the building.

“The Kenya Green Building Society is working with healthcare providers to know the extent and magnitude of people suffering from sick building syndrome, information that can help professionals build better houses that don’t make people sick, using materials that don’t make people sick.”

Such materials don’t have volatile organic compounds (VOCs) and formaldehyde. To know whether the material one intends to buy contains VOCs, Mr Kabuye advises developers to request technical data sheets from the manufacturer before purchase and read through.