In earlier times, land was readily available and buyers could opt out of buying plots with black cotton soils in favor of others with better soils. Currently, the land available has become scarce and expensive so buyers have no choice but take what is available.

Black cotton soil is found abundantly in most regions in Kenya. For example in parts of Kajiado, Nairobi, Rift Valley, Kiambu, Machakos, and Nyanza. Within the Nairobi metropolitan area this type of soil is common in Kitengela, Syokimau, Athi River and even Kamulu areas along Kangundo road.

Why is it risky to build Foundations in Black Cotton Soil?

Black cotton soil, a cohesive soil, is considered a problematic soil for civil engineers. It has characteristics of swelling during rains and shrinking during summer. In both the conditions, it poses problems.

The continuous expansion and shrinkage of the soil creates a very unstable environment to build a foundation on. It is what causes the cracking in floors and walls due to the uneven settlement in foundations.

Special care must be taken into consideration when building foundations on this type of soil. This is why the cost of building is usually higher in these soils.

How should you build on black cotton soil?

There are two common ways of dealing with the soil: one can excavate all of it or have a floating foundation.

Option 1: Mass Excavation

When building on land with black cotton soil, the entire top soil is always removed through excavation using building machinery.

Once the soil has been excavated, you can start construction using the normal strip foundation that is common for residential houses.

The additional costs that the homebuilder incurs here include the costs of hiring an excavator, transportation costs of the excavated soil, and backfill materials.

Option 2: Using floating foundations

Generally, if the black cotton soil is more than 1.5m in depth and the homebuilder has no intention of creating a basement, it becomes uneconomical to excavate the whole of it.

This requires a suspended type of foundation whereby columns are dug till solid rock or firm ground and protrude slightly above the ground level.

The suspended type of foundation is known as the pad foundation. Here excavation will be done only for the load-bearing components of the house, which are the columns and ground beams. These columns and beams will then support the entire structure above the soil near the surface.

Waste water management

Black cotton soil has poor drainage. When constructing soak pits in the terrain with this type of soil, water doesn’t percolate. In stead it stagnates on ground. 

In such areas its advisable to fill in the soak pit with large sized quarry chips to make the soakage faster. Alternatively the soak pit will have to be dug deeper till one reaches the stone.

Please ensure you engage a professional before undertaking any building project.

Need help with your construction project? Talk to us

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If you are a budding entrepreneur who is seeking an impressive return on your investments then construction is the way to go. But first, you must ensure your business is properly registered and meets legal compliance.

The process of starting a construction company is the same as registering any other company but with an additional step of registering with the National Construction Authority (NCA).

There are also some additional requirements for foreigners who want to start operating businesses in Kenya.

How to start a construction company: a step by step guide

1. Register with the registrar of companies

A contractor or construction firm is required to hold a certificate of incorporation from the registrar of companies in Kenya. This means that the firm must be registered as a legal company within the country, either as limited liability, sole proprietorship or as a partnership company.

2. Register your company with NCA

A contractor applying to operate in Kenya must prove tax compliance by submitting the below documents to National Construction Authority (NCA).

• Valid PIN,
• VAT
• Income Tax compliance certificates
• Evidence of Bank Account that has been opened under the name of the contractor company

All the directors must also forward their CVs to the National Construction Authority.

The full list of documents required for registration under NCA can be accessed here.

Before registration, the firm needs to be aware of the class of construction that they intend to apply for. NCA has 7 classifications of contractors depending on the scope of work the company is allowed to undertake. This ranges from NCA 1 which enjoys an unlimited contract value to NCA 7 which can undertake contracts not worth more than sh20 million.

The requirements for each class will vary depending on the category. A company to be registered under NCA 1 is required to have at least one director with a degree in a building and construction-related field while a director with a trade test is required for registration under cadre NCA 7.

The registration fee as well as the annual license renewal fee also varies across the categories ranging from KSh10,000 to KSh50,000 and KSh5,000 to KSh10,000 respectively.

3. CR-12 Letter and AGPO certificate

These are additional steps that only apply to those businesses intending to go for government (national or county) tenders.

You have to register with the Access to Government Procurement Opportunities (AGPO) for a certificate which prequalifies you to bid in the reserved tenders.

In order to apply for a CR-12 letter, a letter will need to be written on your company letterhead requesting Company Registry to give you a CR-12 letter that contains a list of directors in your registered company. You will also need to attach a copy of the Certificate of Incorporation on your request.

4. Additional requirements for foreign construction company.

Foreign contractors are issued with a clearance certificate that remains valid for only a specific period. They are required to satisfy the NCA that they are in Kenya for only that specific project.

The firms are required to lodge an affidavit with the Authority that they shall not carry out any other construction project in Kenya once they complete the project for which they have been cleared.

Foreign firms should also submit a commitment to transfer technical skills not available locally to locals as the NCA may determine from time to time.

Upon successful application, the contractor is issued with a ‘Certificate of Registration’

Foreign contractors pay a registration fee of Sh250,000 and are restricted to categories of tenders they win.

Foreign contractors applying for temporary registration are required to commit to sub-contract “not less than 30 percent of the value” to local contractors.

Foreign contractors are not cleared to carry out work below NCA 1 category.

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In Kenya and many third world countries, most building collapses are manmade disasters. You find that the construction industry has been marred with unscrupulous dealings that compromise the quality of buildings. These may be either by employing quacks to carry out building projects, poor workmanship or even the use of substandard buildings.

Whereas there exists a robust legal framework to ensure that collapses do not happen, we have a very big gap, especially at the enforcement level.

Who is in charge of regulating the Construction Industry in Kenya?

The construction industry is characterized by the intertwining of various players notably the local government, state corporations such as the National Construction Authority (NCA) and National Environment Management Authority (NEMA). When a building fails, it is critical to examine the players and the role played by each.

County Governments

The function of development control is the mandate of the County Governments. In Nairobi,for example, all architectural and structural drawings for proposed developments should be submitted to the planning department at City Hall, under Nairobi City County (NCC), for approval before a building permit is issued.

This is a move aimed at stemming improper use of land and subsequent demolitions as well as check on the growth of unplanned settlements and slums. NCC also carries out inspections on building sites mostly to check on compliance with the approvals.

It is important to note that most of the cases of buildings collapse due to poor construction are in poor neighborhoods where there is little or no inspection. According to Transparency International (2014), contractors and owners of the buildings bribe the NCC inspection unit to bypass the inspection process.

It is the low income earners in search of affordable housing that end up suffering due to poorly designed structures and live at risk of injuries and even death should the buildings come tumbling down.

The National Construction Authority

The National Construction Authority was constituted under ACT No. 41 of 2011, in a move to weed out rogue contractors and reduce the amount of malpractices that have seen the collapse of buildings due to poor workmanship.

Professionalizing the industry will require a complete overhaul of the status quo characterized by quack contractors, an unskilled labor force, blatant disregard of health and safety of workers in construction sites and the existence of several informal businesses within the entire supply chain of construction.

So far, their notable achievement has been registering all contractors under one roof and ensuring relevant classes are given to each as well as accrediting about 150,000 construction workers and site supervisors.

They have also conducted various sting operations in conjunction with the County governments in order to enhance quality assurance and compliance.

The clock is ticking and only time will tell how well the NCA is able to inspect upcoming and existing construction sites to enhance compliance of the rules and regulations as stipulated in the NCA Regulations 2014.

National Environment Management Authority

NEMA was established under the new Environment Management and Coordination Act on February 27, 2009 to care for all issues affecting the environment.

This is the body that should propose effective mitigation measures for significant negative impacts of building construction projects, issue guidelines for the management and conservation of natural resources and the environment during construction and carry out onsite inspections properly and on time.

Currently, the system suffers from inadequate funding, corruption, a lack of engagement with important community stakeholders, gaps or duplications of regulations, and a misunderstanding by society at-large of the benefits of a sustainable project.

These serious issues result in little oversight of development projects with potentially huge environmental impacts. Regulation of construction projects is superficial, reaching only as far as the environmental assessment.

In addition, those agencies responsible for drafting reports tend to falsify them in order to satisfy construction entities.

National Buildings Inspectorate

The National Buildings Inspectorate is a state department under the Ministry of Land, Housing and Urban Development that audits buildings to check for conformity with land registration, planning, zoning, building standards and structural soundness.

In May 2015, the NBI working with the County Government and NCA concluded that out of the 2601 buildings inspected in Nairobi, 226 had serious structural issues and 58 of those were marked for demolition.

According to the law, before any demolitions are carried out, the residents ought to be served notice by the Nairobi County Government to vacate any such residences and accorded ample time to leave.

The building owners likewise are issued notice of the intended evacuation and demolition and given first option to demolish and salvage any materials that they deem useful. Failure to comply would result in forced demolition by the County Government working with the NBI assisted by the National Youth Service.

Non-compliance of residents and building owners coupled with scarcity of resources to carry out forced demolitions has seen unsound buildings still standing to date posing serious risk to their occupants

Industry professionals and professional organizations

Noting that the local authorities are often understaffed with not enough technical personnel, an extra pair of eyes would be the industry professionals.

Depending on the contract agreement, the architect, engineer or even project manager who has been contracted by the developer should offer periodic supervision of the building construction until the building is complete and ready for human habitation.

Professional organizations such as BORAQs, AAK, IQSK, ACMK and EBK exist to ensure their members direct, co-ordinate, design and supervise works executed as per the building contract. True professionals will place the public good before mere financial reward.

This is the concept that is embodied in many of the professions’ codes of conduct.

‘’In principle, we can conclude that though not perfect, there exists sufficient regulation of the sector that seeks the protection and benefit of the public at large.

Strict adherence to the law by all citizens and close monitoring of compliance by the regulatory agencies is the only sustainable approach towards a safe and vibrant construction sector.

Corruption is a thorn in the flesh in this country therefore because residents are on location where all abuses of zoning and building regulations are taking place, they are the most strategically placed to detect malpractice on ground as it emerges before it escalates to complete buildings.

According to our constitution, sovereign power is vested on the citizens of Kenya so it’s about time Kenyans hold their leaders accountable for their actions or lack thereof. ‘’

The post Building Collapse : Poor enforcement of Regulations to Blame appeared first on My Building Code.

Consequently, many millennials would opt for light gauge steel technology if they were made to understand the myriad of opportunities it presents. Sure, we all know about structural or heavy steel as a common construction material favored for large construction projects without which, skyscrapers wouldn’t be in existence.

Steel, unlike masonry, wood and other construction support materials, has a terrific strength-to-weight ratio and is very flexible: it can bend without cracking. That’s why a steel building can flex when pushed to one side either by great wind pressure or an earthquake.

Light gauge steel construction gives you speed, strength and sustainability at a fraction of the weight and at a more affordable cost compared to conventional construction. The difference between structural steel and light gauge steel lies in how they are manufactured.

Light gauge steel sections are cold formed sections, meaning that the sections are shaped into strong “C” or “Z” forms, capable of holding heavy loads, at room temperature.This is in contrast to thicker hot rolled sections, that are shaped while the steel is molten hot to form structural steel.

Light gauge steel is then coated with zinc (called galvanized) to protect it from corrosion. From the manufacturing process, lower production costs are realized since LGS does not involve heat input and its associated expense.

The foundations for an LGS structure will be similar to the conventional masonry building method for example strip footings etc. but will require less reinforcement because steel frames are lighter than masonry frames.

In construction, time equals money. LGSF system, design, production & shipping can happen within days or weeks, instead of months. Because most of the construction components are manufactured in the factory, frame erection and construction at site can begin immediately due to the pieces being exact specification, pre-cut, pre-punched & pre-marked.

No additional work to be done at site. Additional advances in the speed of projects are attributed to the near 100% computer controlled accuracy(+/-0.5mm) of the frame ensuring a near 100% square and straight frame which benefits other trades. Its lightness makes for easy handling on site that contributes to faster erection.

The uptake of LGS in Kenya is now fast growing with developers mainly testing it as a truss structure replacing traditional timber trusses. Unlike wood, steel is stronger and more durable.Steel does not burn or rot and is not susceptible to moisture damage, termites or other wood destroying insects.

It helps preserve our environment for the future by decreasing the consumption of wood. It is 100% recyclable, can be used again and again, without losing its properties.

An economical LGS frame system is increasingly being used in America, Europe, Australia and New Zealand as a serious alternative to lumber in residential construction where wood frame construction was previously popular.

Light gauge steel framing has a few minor disadvantages first being with regard to its fire resistance properties. Although noncombustible and thus will not fuel the fire, the steel studs are directly affected by high temperatures.

Since there is not much mass to the steel studs and joists in this type of construction, the steel trusses and bar joists are likely to be weakened quickly by heat and are prone to early collapse.

An easy way to work around this is ensuring the steel is clad by fire resistant material and provide cavity insulation material.This will protect the steel sections from heating up rapidly when exposed to fire.

The issue of thermal conductivity has been a concern especially since steel is a good conductor of heat. This could potentially result in increased heating costs in cold climates, and in hot climates heat gain could result in moisture damage. Again, insulation placed between the steel frame (batt insulation), will give a better overall thermal performance of LGSF walls.

The pros far outnumber the cons and the technology can be widely used in residential, commercial, and industrial construction.

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