Substandard buildings still coming up since sector regulator’s hands are tied

In the densely populated Pipeline Estate in Embakasi, Nairobi, two multi-storey residential buildings just metres apart are coming up. Construction on  both has reached the first floor, and from a distance, everything seems just fine. 

But a closer look at the buildings reveals that they are on swampy ground, with no indication that any measures taken to avert the risks of building in such an area. Just a kilometre away are two other residential buildings, whose ground floors are almost immersed in water,  a likely pointer to is likely to happen to the buildings being hurriedly put up in the area.

Yet these are not isolated cases; there are many such buildings coming up all around the city’s middle- and low-income settlements.

The population explosion in the city has led to a sharp demand for housing, and it is in an attempt to solve this problem that unscrupulous developers are building these death traps.

But how are developers able to continue building these substandard structures, a number of which have collapsed?

According to the National Construction Authority (NCA), the industry regulator, high construction costs, statutory fees, supervision and tedious bureaucratic processes involving multiple agencies has resulted in developers circumventing the approval process, leading to substandard constructions.

NCA Executive Director Daniel Manduku cites the use of substandard materials and failure to engage professionals in the supervision as major contributory factors. He notes that after getting professionals to design a building — which is subsequently approved by the county government, the National Environment Management Authority (NEMA) and the NCA — some developers drop the consultants, who should supervise every stage of the construction, in order to cut costs.

He adds that after getting the necessary approvals, some developers disregard the professionals’ advice while others even go to the extent of building by themselves.

The NCA says  that most problems occur as a result of developers’ failure to incorporate competent professionals such as engineers, architects, quantity surveyors and contractors.

“So more often than not, that is the missing link. In fact, every construction failure is as a result of those links; you don’t use professionals, or you don’t use a registered contractor, or you disregard what was approved,” he says.

“For example you find someone has three floors approved for construction but he adds another two floors, so, obviously, you are stressing the foundation and the structure might not withstand the extra load,” he points out.

Other mistakes developers make are changing material specifications, using the wrong proportions for concrete, and using substandard or inadequate materials.

He explains that  standard concrete,calls for cement, sand and ballast in the ratio of  1:2:4. This means mixing one bag of cement, two cubic metres of sand, and four cubic metres of ballast. However, some developers use  a 1:4:8 ratio instead.

Similarly, an engineer might recommend the use of steel bars with high tensile strength, only for a developer to use weaker material.

While developers who do this save money, they seriously compromise the strength of the building.

Mr Manduku says that some developers do not allow the concrete enough time to cure. 

“Developers who are in a hurry think the recommended 28 days are too many so they reduce the time to, say 10 days. So you find that even if the concrete was properly mixed, it does not attain its required strength and within no time you find structural failure,” he says.

Mr Steven Oundo, the chairman of the NCA board concurs, adding that some developers engage unregistered contractors, who lack the necessary competence, while in some cases, corrupt contractors do not take the building materials for testing to make sure that they are appropriate.

“When a building collapses, it might be due to of a series of problems. For instance, if you get the foundation wrong, then the building will collapse. Use of untested and substandard materials and failure to follow specified timelines during each stage of the construction also contribute to this,” he explains.

Mr Maurice Akech, a structural engineer, says that a building can collapse as a result of the material used with regard to placement, size, lapping, concrete curing time and a poor foundation. Additional reasons include incorrect ratio or material constituent, non-compaction, and wrong steel strength. 

He asserts that getting the concrete mix right (not using low-quality cement or mixing sand with silt), as well as its compaction, are paramount, to ensure that it is of the desired strength.

“For lack of vibrators, some contractors do not remove air from the concrete, resulting in air pockets in the mix, compromising the quality of the concrete.”

Mr Akech explains that good quality steel might be used, but of the wrong strength or size, or might placed at wrong intervals or  badly lapped (overlapping of reinforcing bars), resulting in a substandard building.

“Make sure that steel is tested to ascertain its quality, placed at intervals of 10-20cms, has long laps and is of the required size,” he says.

He add that to ensure that the structure that is built is sound, a geotechnical investigation must be carried out to determine the type, size and the depth of foundation to be dug.

In addition, blinding (spreading a thin layer of concrete on the foundation), must be done to prevent the steel from getting into contact with the soil. The reinforcement (steel bars) should also be of the recommended quality and appropriately placed, depending on the  height and use of the building.

“After excavation, an engineer should verify whether the levels reached and the type of soil there can support the building. The columns (pillars) and reinforcements have to be tied at the same time, and correctly,” Mr Akech says.

He adds  that the concrete must  be allowed  the recommended 28 days to cure, and one should only erect columns on a foundation after at least three days, and  must have supports for them when placing  slabs on the  floor above.

“In a swampy area, a raft foundation (a continuous slab that covers the entire footprint of the building) is recommended as it regulates non-uniform weight that can cause cracks, and the concrete should also be properly hydrated to keep its surface wet all the time.”

His views are echoed by Mr Manduku, who explains that building in swampy areas requires special attention, adding that what ails buildings in such areas is purely a design issue. 

He says suggests that a pile foundation, where columns are pushed deep into the ground to provide a solid base for what is constructed on top, be used. 

“Design the foundation depending on the area. The mistake we make is that we use the traditional strip foundation in a swampy area. We have to get the appropriate foundation for a particular type of soil,” he points out.

Mr Manduku explains that one can even have a mix of the foundations, such that  some areas have  pile while the others are raft and  some even strip (a strip of concrete  under the load-bearing walls), depending on the results of the geotechnical test. To do this, you must get the right structural engineer to draw the appropriate  design and supervise to ensure that it is followed.

“We know of countries that are swampy but have safe buildings, for example Thailand. Most of the capital city, Bangkok, is in a swampy area but it was appropriately designed,” he says.

He also warns against speeding up the construction of a structure against the advice of professionals in order to cut down costs.

Mr Manduku advises that before starting  construction, you  should ensure that the land is ideal for the intended structure.

The developer should then confirm that the land matches  the zoning requirements, which are stipulated by every county government through the Physical Planning Act, and indicate  the types of structures that  may be put up in  particular areas.

RESPECT ZONING LAWS

“Construction starts with identifying the correct piece of land, by correct I mean legally, it should be  land you own, not disputed and not in the public interest zone, not  riparian or a oad reserve.

“Then get a brief of what you want to build; is it residential house for personal use or residential apartments. We have areas like Karen, where you are allowed to build only dwelling units, so make sure that what you want to build is in line with the zoning regulations,” he adds.

He says  tenants should  look out for problems  like visible cracks; doors that do not lock properly; windows that jam, meaning there is a shift in the structure; broken pavements, meaning the columns are puncturing the ground; and crooked beams, which are structural failures showing  that a building is not safe.

“Even a layman will see the above structural failures but to ascertain everything, we need to take an x-ray of the columns and beams and we will be able to tell if the building is going to fail,” says Manduku.

On the way forward, Mr Manduku cites lack of coordination in an industry with many players, fragmentation of the industry, with each player regulated by its own regulations and legislation, and lack of enforcement and prosecutorial powers vested in the NCA as some of the problemss that have hampered the fight against substandard buildings in Nairobi.

“The NCA Act does not give us powers to go beyond what is provided therein. We need enforcement powers because we leave the enforcement to other government agencies, which has not worked very well. It is sad that even the offenders that we identified have never been brought to justice. You need to set an example for people to adhere to the construction rules,” he notes.

But he is optimistic that all the hurdles will soon be overcome as the authority  has moved to Parliament seeking to amend the NCA Act to give it powers to enforce the rules and also prosecute offenders.

“We have moved to court to put a stop to dangerous constructions and I think we will succeed,” he says.