Saturday, 10 December 2016

Before You Demolish That Building: Consider Underpinning and Retrofits - Engr. Osaz’ ENOBAKHARE


Building collapse continue to dominate industry events over the past few years. There are many defective buildings waiting to collapse and the owners of some of these buildings are not particularly sure which way to go in fixing the problem. 

Apart from being counter-productive investment-wise and attracting attention in a negative way, having a defective/sick building can cause the owner to be just as sick as it is because of the inconveniences that it brings coupled with uncertainties and strings of complaints. 

What readily comes to mind or the popular advice is ‘bring it down and rebuild’. This demolish and rebuild option is often very expensive and can be really wasteful, even though some others argue that it gives birth to something new. What difference does it make? Using underpinning and retrofits techniques, a defective building can be restored completely and made to look astonishingly new at a much reduced cost.
 

Sometimes owners of such properties are forced to sell them at some incredible prices just so that they do not continue to endanger the lives of the building occupants as well as to avoid incurring the wrath of the law should it collapse. 

But having worked on a couple of defective buildings over time, my team and I have discovered that not as much money and time is needed to put these kinds of buildings back in shape using underpinning techniques as it will take to pull down the entire structure and re-build. 

For instance, it only cost about 8 Million Naira to underpin and retrofit a defective block of 4 flats located on the Lagos mainland completed in less than 7 weeks. However demolishing and rebuilding would have cost not less than 20 Million Naira; that’s a whopping 12 Million Naira difference which is enough to build two units of 3-bedroom bungalows extra. Besides it is common knowledge that it would take a longer time to complete.

 

The cost advantage is far greater in larger buildings. An estimate for the underpinning and retrofits of an existing defective three-floor warehouse shown in the picture (which has tilted by about 75 degrees to the horizontal almost leaning on the nearby building) was pegged at 27 Million Naira (including the cost of all external works) to be completed in 13 weeks but the estimated cost of demolishing the entire structure and rebuilding it amounts to 68 Million Naira. Once the underpinning and retrofit work is completed, it would be vertically upright and renewed.



The technique of using underpinning operations to restore defective buildings is not new, what is surprisingly new is the appreciation of this technique in Nigeria. It’s a similar cost-effective concept as used in other engineering sectors e.g. overhauling a facility using Turn-Around Maintenance (TAM) approach instead of demolition and redevelopment. Again, it has been established that underpinning extends the life span of the building equivalent to new construction and keeps it safe throughout its life span. Isn’t it too hasty to demolish? Talk to a professional Structural Engineer. 

Constructing Soak-away Pits/Septic tanks that never fills up - Engr. Osaz' ENOBAKHARE

When a septic tank gets filled up, it tends to put a frown on the users’ faces; not necessarily because the worst thing just happened but because they start feeling the nauseating odour almost immediately and then the cost of transferring the wastes comes to mind. They must invite a waste disposal agent to do the needful or else they will be unable to use their closets! Well, those days are winding out fast with the introduction of soak-away pits or septic tanks that never fills up.  


Just in case you are wondering if there is any difference between a septic tank and a soak-away pit: A septic tank is designed and built like an underground tank or container usually with reinforced concrete, blocks or bricks. Essentially, it is closed on all faces with a small opening only at the surface to allow the escape of waste gases and for a hose to penetrate during pumping-out operations. It is highly recommended in areas with high and moderate water tables (e.g. from 0 - 10m from natural ground level) and areas susceptible to flood. On the other hand, Soak away pit are useful in areas of low water table.



They are built such that they are only covered at the top and sides. The bottom is left uncovered so that the waste water will soak away naturally into the earth leaving the solid wastes behind which begins to decompose as soon as the pit becomes fairly dry.  Like Septic tanks, a little portion is cut open on the top to allow for the required ventilation that aids the drying out process within the pit. These portions are usually protected such as will not permit the passage of rain or surface water into the interior of the pit or tank.

Modern septic tanks or soak-away pits are built like wells within a small diameter of about 1-metre thereby saving space while maintaining its functional requirements. The joints in such systems are adequately sealed, the bottom surface of the first rim below is well compacted and blinded before the rim is placed and subsequently loaded. 

The back fill is also properly done to prevent excessive deflection. For septic tank, the entire bottom is covered but the reverse is the case with soak-away pits. With the aid of a drilling machine, a hole of about 75mm is drilled at the side of the topmost rim above ground level to accommodate a pipe that will convey waste water that rises to that level into a chamber just beside the pit. A pipe is also connected in a similar manner to the other end of the chamber which conveys treated waste-water directly to the nearby drain (otherwise referred to as gutter). 
Soak-away Pit or Septic Tank constructed with Reinforced Concrete Rims
Special Chamber for treatment of Sewage/Waste water


Within the chamber, a net trap is fixed at the entry point of the pipe to ensure that no solid waste is allowed to be passed into the chamber. The chamber is constructed in such a way that allows the user of the system add a bio-pod or pour camphoric oil or other approved eco-friendly mixtures into the chamber to treat the waste water before it is allowed to flow into the pipe that takes it directly to the public drain. These mixtures are very cheap and readily available. A lock and non-return valves are built into the exit point of the chamber so that the user can control when the treated waste-water would be allowed to flow out of the chamber. The process can be carried out at any time of the day.



This concept is based on the fact that the solid waste matter in septic tanks/soak-away pits are very little in relation to the space they occupy even after many years i.e. if waste water only is drained out of the system, the volume of solid waste (shit stuffs) left is often insignificant. It is believed that if you can get the waste water out through a natural process, then the pit/tank may never get full throughout the building’s life span, especially for residential applications. 

The conventional system which places the backyard as the best position for sewer systems is now being countered by this contemporary approach which allows it to be built most conveniently in the front of the main building close to the perimeter fence and the public drain. It can be constructed such that a car can park over it without causing any problems. Using this system ensures a decentralized waste water treatment solution which is healthy to the users, the public and the environment. It is convenient, cheaper and easy to use and finally ensures that the septic tank never really fills up.   

Building Cheap: The Laterite way - Engr. Osaz' ENOBAKHARE

Nowadays building designs without ornamental columns (otherwise known as fanciful pillars) either in front, the sides, back or in the interior are often seen as old-fashioned. Interestingly most of these columns are either non-load bearing or partially-load bearing but due to ignorance, most of these columns are often over-strengthened and thus wasteful cost-wise; its like giving an empty trolley to a giant to carry when there are heavier loads yet to be moved. Basically, ornamental columns are often designed to carry artworks that add beauty to the buildings exterior or interior. They come in various cross-sectional shapes; circular, square, oval, rectangular, etc. However aesthetically appealing on completion, the cost of constructing ornamental columns especially the reinforced concrete and steel forms are considerably high in relation to other elements of the same shape, size and function in the building. Similarly, the use of Sandcrete blocks for walls and reinforced concrete for frames (i.e. columns and beams) account 

for a sizeable proportion of the cost of building projects (usually about a quarter of the gross construction cost) hence the emphasis on low-cost technologies to lower these costs.

Today, the use of Laterite bricks to replace reinfiorced concrete columns and the traditional Sandcrete hollow or solid blocks is increasing by the day across the country and elsewhere; not just because they are relatively inexpensive and durable but for their fair resistance to tension and compression when bonded and their decent stability. The rate at which developers are keying into this low-cost technology suggests that the use of blocks may soon fade out and block factories may be forced to convert to brick making.



From industry estimates, the use of Laterite bricks for block walls and columns where suitable, reduces the cost of these items of work by about 15 - 25% depending on how widely it was used. Laterite bricks are cheap because the cost of the main constituent material Laterite and the cement-sand ratio is quite low compared to the cost of producing the popular Sandcrete type. Using Laterite bricks in place of reinforced concrete for columns for instance, completely erases the cost of buying re-bars (i.e. Iron rods) as well as the cost of employing the service of a steel fixer to cut and fix the steel. Overall they meet all the established functional requirements, including the fact that they come already finished.

How to build underground apartments that’s not a ‘burial ground’ - Engr. Osaz' ENOBAKHARE

Living underground saves you from the stress and headaches that the noise and buzzes of the city brings especially for those living in industrialized cities; cities that never sleep like Lagos. Research has shown that adequate noise control reduces stress levels and reduced stress levels in humans is synonymous with longevity. 

Everyone wants to live long and wealthy but living long in big and busy cities where wealth is perceived to be abundant means accepting stress as part of life. Avoiding stress and promoting healthy and peaceful living could mean living below earth but not as a corpse though. Besides, it is generally safer to live under the ground especially in war-torn or conflict-prone regions to avoid straying bullets and other forms of attacks. 



At a time when insurgency and rebellion has become a part of our society, there is no better time to tilt our line of thoughts towards the design and construction of basement apartments at least for the sake of safety and peace than now.  However glaring the benefits of underground or basement apartments are to occupants, most Nigerians haven’t been able to fully take advantage of it either because of the false fears of the cost implication of such a project or the erroneous belief that there are no indigenous contractors/builders that can construct them properly.
Underground/Basement apartment with Swimming pool
City homes and mansions without basement apartments are like jeans without pockets; they are actually under-utilized. However truth be told, a lot of work goes into the construction of basement apartments; from stopping water to ensuring adequate lighting and ventilation all day long and then working towards the attainment of all other established functional requirements; a process in tandem with the old saying that ‘nothing good comes easy’. 

Here are few tips to guide you;

Confirm that no existing laws, bye-laws or regulations bar you from putting up a sub-surface or underground apartment on that land; get a comprehensive architectural, structural and services designs that takes care of space arrangement, lighting and ventilation provisions as stipulated in the relevant design and building codes as well as other functional requirements and get statutory approvals; then, employ the services of a qualified contractor to handle the job. 
The work processes are as follows; excavate the portion of land to build the apartment using manual or mechanical methods; protect the earth from collapsing by using earthwork supports commonly made from timber or structural steel; construct the basement floor slab over a bed of hardcore and damp-proof membrane using suitable materials like stainless steel or reinforced concrete of appropriate mix. Construct the external walls of reinforced concrete or solid blocks/bricks and depending on the water table, fix a damp proof membrane over the wall surface and blind properly to stop water ingress and insert a damp proof course to stop water capillarity (upward); allow for openings at surface levels according to the design and ditto for all other works. Only special finishing materials designed for basement structures should be used and care must be taken not to trap workers inside the earth or allow them suffocate in the process of constructing. 



The cost of constructing a basement structure is not always exceptionally high. For instance, from industry estimates, a budget of 4 Million Naira can complete the construction of a room self-contain basement apartment in the Lekki-Ajah axis of Lagos (an area with generally poor soil conditions and high water table); only a 55% increase from the cost of constructing the same structure on a surface level in the same area. On the mainland where the soil conditions are relatively better, the cost is pretty lower (down by about 30%). Interestingly, for Estate developers, building sub-surface studio apartments is an added advantage in the market. By and large, the advantages of underground rooms are far beyond mere additional living spaces on the same plot. 

Avoiding Building Collapse: If the Foundation of Your Building is Weak Don't Panic, Just Underpin

Most building collapse scenarios across the world have been attributed to faulty, weak or unstable foundations/sub-structures or issues of overloading of some structural members within it. Some others are a consequence of partial or total failure of a member or several members, elements or components of the building/structure occasioned by several forces. 

Many people wonder if there is ever any remedy to damaged or poorly-constructed foundations and defective buildings. The good news is -Yes there are. For buildings or other structures with poor, faulty or weak foundations, underpinning operations can be carried out to correct such defects without aesthetic distortion or demolition. Similarly, in buildings for which extra-loading is intended to be introduced (due to remodeling or change of use) beyond the original design, underpinning is also recommended. In the later case, it is important to first carry out an in-depth assessment of the strength of the foundation in order to ascertain if it can sufficiently sustain the additional load and safely transmit it to the ground on which it rests. 
Generally when a major renovation, repair, addition, alteration or conversion work is to be performed on an existing building of one-storey or more, a structural integrity test on its load-bearing elements and components should be carried out by a structural engineer to ascertain current structural needs or deficiencies. This assessment should form an essential part of the condition survey of the existing building from which the schedule of dilapidation will be prepared and submitted for the purpose of measurement/valuation and subsequent work.


The structural integrity test aims to determine the mechanical properties of the soil stratum just beneath and at the sides of the building’s foundation as well as the current strength/stability status of all its structural members e.g. foundation members, beams, columns, load-bearing walls, shafts, floors and roof and the restrictions imposed during this operation.

If the foundation is not strong enough to sustain the new load you want to add to the building (for example an extra floor), additional weights may be introduced to the foundation. However if its strength is ok but will deflect largely when transmitting the entire load to the subsoil on which it rests, the foundation can be taken to a safer depth using micro-piles, pre-stressed connections, jet grouting, etc. or by simply improving the supporting soil’s mechanical properties, its stiffness or bearing capacity in what is known as an underpinning operation. 
Underpinning operation on an existing foundation of a building 

However, only a competent professional foundation or structural engineer must be allowed to manage this high-risk operation to avoid any disaster ranging from underground trappings/caving-in, structural disintegration, to uncontrolled failures or collapse which may pose a huge threat to adjoining structures and facilities, losses and avoidable injuries or death especially in medium and high-rise buildings or structures above 7m from natural ground level.


In Nigeria, most building owners are ignorant of the existence of this cost-effective technique and would rather pull down the entire structure and put up a new one. Research has shown that apart from saving time, the cost of underpinning foundations is generally much lower than the cost of demolish-and-rebuild. In addition, underpinning operations saves time and retains the structure’s original efficiency or even gives it a greater efficiency throughout its life span. 

The best way to sand-fill a water logged site - Engr. Osaz' ENOBAKHARE

The most suitable soil type for filling water logged lands (or lands with high water table) to make it stronger and stable enough to sustain foundations or sub-structures to be constructed over it is any highly draining soil like sharp sand. The common practice which is to fill with only Laterite (or red soils) then construct a concrete slab or foundation or interlocking pavers directly over it often yield in poor results; hence the reasons for the depressions that shows up at various portions on the surface of a poorly sand filled land which may consequently affect the overlying structure.

Unlike Laterite or red soil, highly draining soils like sharp sand barely retain surface and ground water, and do not behave abnormal across seasons (from dry to wet or vice-versa). For instance, because of the plastic nature of clay/red soils, they behave stable during the dry season and unstable during the wet (or rainy season).


Therefore if a foundation or floor is constructed directly over it in an area with high water table even with hardcore filling on it, it is most likely to start settling in-differentially or failing horizontally throughout its surface or longitudinal bearing and vertically downwards at various portions as we migrate from one season to another leading to visible cracks on the floor or from the foundation up to the roof after a period of time. 

These cracks are often persistent and will continue to resurface until proper re-work is done. If left unattended to, it may degenerate into collapse of the structure over time. Sharp sands or suitable equivalents also perform well with changes in ground and surface temperatures in the day and at night giving the foundation or floor greater resistance in the face of extreme temperature or weather conditions.

Site sand-filled with sharp sand on a bed of Laterite 


However because of the cost implication of using sharp sand or its equivalent as the only filling material for the site, the suitable alternative practice is to first fill the land from the depth of suitable sub-soil or from the existing depth to a reasonable level with Laterite or smooth sand which is relatively cheaper before introducing sharp sand to complete the fill up to the marked out level which is often above the water table and road or drainage level. 

This way, the stiffening advantage of Laterite or smooth sand combines with the merits or good qualities of sharp sand to give an acceptable degree of strength, resistance and stability.
 It is instructive to note that when filling a land, precaution should be taken to ensure that the filling sand or material is well leveled and compacted to allow natural flow of surface water to the drains and to prevent excess air voids or gaps respectively in order to function to full potentials. This process can be done manually or mechanically or chemically or a combination of any of the trio depending on the nature of the project. It is better to get it right at the sub-structure level before constructing the super-structure to avoid re-works and to reduce maintenance cost in the future.

Analyzing the latent cost of Estate Infrastructure: What developers should know - Engr. osaz' Enobakhare

A residential estate without basic amenities to support healthy and safe living is no better than a Slumville, hence the need for an estate developer to make adequate arrangement for the provision of critical estate infrastructure when planning a housing estate or allied settlements. 

Often than not during the cost planning stage, developers tend to under-estimate the cost of providing the requisite infrastructure within the estate and before long, they battle with capital inadequacy and loads and loads of complaints from clients/occupiers. 

Although it is common knowledge that investments in housing estate developments in the Nigerian space yield high returns and have made multi-millionaires of some ordinary people, poor cost planning for infrastructure can make a mess of such a great venture. Estate infrastructure includes perimeter fencing, motorable road network, drainage/sewer, refuse collection and renewal systems, CCTV/Security furniture, water works, estate electrification, lighting, recreational centre, landscaping and beautification, learning centres/schools, shopping mall/market, security house/police station, estate office, estate pharmacy/medical centre, etc.



In Nigeria, the cost of estate infrastructure is nearly half the cost of putting up the entire housing units within the estate or even more depending on the nature of the site and the occupier-capacity; this cost is normally a multiple of the initial value of the land, therefore if the cost assigned to infrastructure at the planning stage is not within this region the developer may be heading for some horrible shocks as the project progresses. Some estate projects are at a halt today because the developer has sold out almost all the plots or housing units without ensuring adequate budgetary provisions for infrastructure and they are now at a dead end –no more properties within the estate to sell and raising money to complete the infrastructure works becomes extremely difficult.


From recent industry estimates, the cost of basic estate infrastructural development per acre of land hovers around 20-25 Million Naira and 45-55 Million Naira for affordable and luxury housing estates respectively. Of this cost, perimeter fencing, roads, drainages and electrification often amount to at least two-third of the total infrastructure budget. As at September, 2015 a thorough cost analysis of a proposed 1500-unit affordable housing estate to be built on 200 acres of land in Abuja shows a gross estate infrastructure cost of 4.63 Billion Naira while the combined cost of the housing units (comprising of bungalows, duplexes and blocks of flats) was pegged at 10.74 Billion Naira; amounting to 43.11% in excess of the estimated cost for the design and construction of the actual housing units. 

These costs, some of which are often difficult to deduce at the initial planning stages are relatively significant and should be taken seriously as many private and public estates with beautiful cartographies are now a shadow of themselves. 

For estate developers who sell serviced plots only, it is important to correctly incorporate the cost of estate infrastructure into the cost of the traded plots in such a manner as to sufficiently take care of infrastructure without incurring any financial losses. 

Using several low-cost, cost-effective and maintenance-free construction methods/techniques like the rubber-road technology for the construction of estate roads, the PHP technology for perimeter fencing and drainage construction, solar LED lighting techniques for street lighting, etc and by employing the service of a competent contractor that can handle all aspect of the work singlehandedly in order to save the cost associated with multi-contracting, developers can drastically reduce the cost of providing estate infrastructure in the short and long-term while maximizing profit.

How to Select a Good Contractor for your Project - Engr. Osaz' Enobakhare

In any construction project, the client or project owner is the major stakeholder; hence any action or inaction by a client in relation to his or her project can either make or mar the project delivery. It is therefore very important that project owners become increasingly professional in the discharge of their responsibilities on their building/construction projects. 

Over the years it has been observed that most of the reasons for the poor delivery of construction projects are essentially a consequence of the poor selection of the main or sub-contractor(s) handling the project often by the client or his or her agent or consultant.

Selection of a contractor based on false recommendation, financial posture, ethnicity, unverified credentials, age, tribe, race, personal affiliations, family linkages, nationality, gender, religious/community affiliations or as the case may be rather than competence is increasingly risky.



There have been piles of reported cases and cries in various quarters of gross misconduct, misuse or diversion of project funds and sharp practices by several contractors. Some others have employed the services of contractors who have constructed buildings that have collapsed or are waiting to collapse. Others claim that their contractors never stop asking for more and more money; an incredible variation from the original contract sum. 

There are also cases of unsuspecting clients especially based abroad falling prey of fake, unreliable and unqualified contractors. That a person has been building since 1900 does not qualify him/her as a competent building contractor. 

There is a need to leave the comfort of your homes or offices to do a fair appraisal of the competence and reliability of a contractor before employing his or her services on your project. For project owners based abroad you may have to make some extra phone calls. This process for this purpose of this piece is known as due diligence. 

The following few steps will guide you: Before making your final choice on a contractor for your project, you should; 

- Look up their profile e.g. via the internet - Ask relevant questions such as; the person’s office address or any construction site he or she is currently working in order to pay a visit and make some personal observations of his/her attitude and work style.



 - Inquire about the key person’s academic qualification and details of past projects. Visit one or two of their past projects to verify. 

- Ask for the firm’s certificate of incorporation, professional licenses, financial capacities etc and verify their authenticity because the law does not recognize any business agreement you enter with an unregistered firm. 

- If you are satisfied with their profile, ask specific questions like: Can you work in this kind of environment? Have you done this kind of project before? What kind of foundation is most suitable for this kind of soil on site? How would you construct this kind of foundation? What are the cost implications of alternative methods? How do you manage variations? Etc. If you get a ‘Yes’ as an answer to all your questions, then it is enough reason to be suspicious. Most tried and trusted contractors are not akin to hyping themselves or false bearing. At least a truthful ‘No’ as an answer to some questions, with reasonable explanation is ok. Always ask the ‘how’ question.



- If you don’t like to entertain any aorta of variation in the original contract sum agreed with your contractor, then you must insist on a fixed-type contract and document your contract agreements; signed and sealed. That way even if a justifiable reason for variation occur order than such as was provoked by uncontrollable events like force majeure, very sharp inflation and malicious damage from external sources, the contractor is obliged to complete the project within the budget.

Using Dry-Cementized Construction and Re-Use Techniques For Mass Building Construction To Save Cost and Time - Engr. Osaz' ENOBAKHARE

A term of contract for a project may require a contractor to construct a large number of buildings (say 50-100 units) within a short period of time (e.g. 2-3 months). Often than not in such cases even when the conditions are well spelt out, most local contractors readily accept the job without necessarily designing a workable blue-print on how to complete the project within the stipulated period of time, hence few days to the expiration of the deadline, they are still staggering at 30-40% completion.

Project planning is very crucial to the successful delivery of any project but planning a project in isolation of the technique to carry out the actual work itself is effort in futility because it is the work on ground that matters more than the print on paper or soft notes.

For construction projects where pre-fab or pro-fab construction techniques are considered expensive, a smart combination of dry-cementized construction and re-use method could be adopted. 




Most buildings in this part of the world are made from brick and concrete hence a good case for the use of dry-cementized construction. In using this method, the volume or type of cement used in the mix for the concrete elements and components within the structure are increased so that they dry or harden very quickly such as will enable the speedy removal of the formwork. For instance a structural design specification of a minimum concrete mix of 1:2:4 (i.e. 1 part of cement to 2 parts of fine aggregates or sharp sand and 4 parts of coarse aggregates or granite) can be constructed at 1:1½:3 (i.e. 1 part of cement to 1½ parts of fine aggregates to 3 parts of coarse aggregates) which is a more stiffer mix. The idea is to increase the cement content in the mix par aggregates so as to dry quickly while still maintaining the required strength. Alternatively rather than use ordinary Portland cement which is the most common and readily available, rapid hardening cement could be used as a suitable alternative while the original mix is maintained.



Dry-Cementized construction and Re-use Techniques
can be used to save cost on large projects


 Where the common timber/wooden formwork is to be used, the inner surfaces of the timber is lined with water-proof material (e.g. polythene covering) that does not react with the concrete so as to reduce the rotting of the wood; making it suitable for re-use. Practically, a good wood can be re-used for up to 10 times or for 10 buildings. The carpenter fabricates the formwork in such a way that it can be removed and transferred with ease.  This way the cost of extra volumes of cement used will be compensated by the re-use of the timber formwork.


It is very important to note that when adopting this method, a controlled proportion of water is used; a little less than the usual volumes. In the end, the concrete will set faster and the formwork is ready for detaching in about 24 hours for non-suspended elements (e.g. columns) and about 7 days for suspended elements (e.g. upper floors) – saving roughly 48 hours and 14 days for non-suspended and suspended elements respectively.  

How Instant Messaging and Mobile Banking Help Save Project Cost and Time - Engr. Osaz' Enobakhare

    
Finance is an integral part of any construction project so is communication. In fact there would be no construction project in the first place if money and people are not involved. Therefore smooth, constant and healthy interaction between all stakeholders in a project is very important as well as prompt and adequate disbursement/distribution of project funds to areas needed. Advancement in technology has made communication and payments a lot easier yet many local contractors have not keyed into it.

In the past, communication on site was done basically through public address systems, phone calls and SMS which are pretty expensive up to the extent that the walkie-talkie became a highly-cherished engineer’s work tool; artisans who normally couldn’t afford them had to rely on second-hand instructions or information or often had to move out of their work stations in order to gain access to a telephone to pull a call through to their supervisors especially on large sites. 

But today the story is different; with instant messengers like Whatsapp, Viber, Wechat, Yahoo, etc on simple smart phones and tabs everyone on site can communicate seamlessly at very low cost. 



By ensuring that having an instant messenger on your mobile phone is a pre-requisite for site employment, a project manager can save up to 70% of the total cost of communication through e-messengers.


Flexible payments to suppliers and workers through mobile/internet banking channels are in vogue now. Modern day contractors/supervisors now make payments for supplies through their phones or tablets and the receipt of payment is transmitted through the same medium. For instance, using an instant messenger like Whatsapp, once a nominated supplier has delivered the required materials to site, he or she simply sends a multimedia message (i.e. texts plus images) of the materials on delivery via Whatsapp notifying the contractor of the supply. In a split second the contractor receives it on his mobile device wherever he or she is at the time and replies promptly. 
Seamless money transfers and instant messaging
promotes construction speed



On the same device, he or she opens his mobile banking app and transfers the money for the item directly to the bank account of the supplier. Immediately the transfer is completed, he receives a confirmation SMS from his or her bank and a response from the supplier via the same medium. The supplier then prepares an original e-receipt of payment or alternatively fills out the paper-type manually (crossing out the customer’s signature column/space indicating that the customer is not available to append a signature), scans it or snaps it with the phone and forwards it to the contractor. 

The receipt can be stored immediately in an e-file on the mobile device or printed out and stored manually. In practice, all these processes takes less than 30 minutes depending on the network’s data signal strength; only a few Megabyte of data is consumed and some hundreds of Naira is deducted for the bank transaction for an inter-bank transfer; a transaction that would normally take hours and sometimes days in time past.

It is now safer to conduct business within the e-environment. Traditional methods of issuing cheques or paying cash are increasingly risky, time-wasting and make accounting laborious. In more organized sites, all site workers get their wages as at when due directly in their bank accounts through mobile banking and a pay slip is automatically generated and sent to them via instant messengers. All requests, complaints or issues related to the payment by any worker is transmitted via the same medium at once and the employer can respond promptly. This process completely wipes out the usual queues at cash offices and discourages manipulations and site robbery/theft.



The system is very flexible and makes project funds much easier to organize, distribute and track or trace. Project accounting becomes a lot easier for SMEs, MSMEs and Large scale organizations because if all payments throughout the life cycle of a project was made through a particular medium, accounting data can be extracted directly from the transaction history automatically generated by the app and subsequently transferred to the balance sheet. Discrepancies and misappropriations can be easily detected since each transaction details containing relevant information like transaction volume, date, time, account name and number, and remarks/notes are stored automatically. Using the duo of instant messengers and mobile banking apps in an organized manner saves project delivery time, reduces overhead and logistics costs and increases profit.

Avoiding Re-works and Wastage During Construction -Engr. Osaz' Enobakhare

It is not unusual to see re-works on construction sites all over often occasioned by poor interpretation of working drawings, workers not working to engineer’s or builder’s instruction(s) or paying inadequate attention, faulty directives, false construction, site accidents, force majeure, alterations to designs/specifications, malicious or free damage, inconsistent use of materials, poor use of skills, misapplication, mistakes/errors, misappropriation, government/regulator’s actions, mal-handling, etc. 

Generally, re-work is a term used to describe all repeated items of work carried out usually to correct a defect or to allow for an alteration or modification to a section of work during construction. For instance if a block wall in the kitchen area of a residential building under construction was not properly set, any work done to correct the defect observed is referred to as re-work or if the tiles original meant to be installed in the living room was used in the toilet, any attempt to correct the situation is considered a re-work. The re-work itself could involve demolition or some form of breakage, loosening, reconstruction, re-positioning of the affected element or component of the structure, etc.




However for most re-works, there is an almost equal and negative re-cost.

Re-works always arise so they remain an indelible part of the construction process. But the frequency and size of re-works could be reduced to the barest minimum if deliberate efforts are made to forestall them. From common knowledge, wastages and re-works often account for roughly 5% of the entire construction project cost and could be more depending on its magnitude and frequency throughout the project life cycle.  

The cost implications of re-works and wastages resulting from re-works or other construction processes are substantial and significant. If treated with loose gloves, they can affect the project cost and time badly, sometimes leading to abandonment of the project. In extreme cases, re-works may involve demolishing a better part of the structure which may put the contractor at a huge loss.



To avoid re-works and wastage, it is important to;
-          Ensure that all working drawings (I.e. survey plan, site plan, site layout, architectural drawings, structural design/drawings, mechanical/HVAC/plumbing drawings, electrical/lighting drawings, etc), specifications, schedules (i.e. material schedule, plant/equipment schedule, labour schedules, etc.), quantities and estimates for a project are properly studied and reconciled before starting work on site. 

      Any discrepancies observed in the process should be identified and fixed immediately or else such errors may be transferred to the ground. A simple re-design which would have cost close to nothing and can be completed within a short time may later result in a re-work which would eat deep into the project fund and time if left unattended to.





-          The interpretation of the drawings, specifications, timelines etc should be made to all key members of the project team including professionals, suppliers, sub-contractors, fore-men and sometimes gang leaders in such a way that everyone comprehends the nature and extent of the work to be done before commencement of work.

-          There should be effective communication between workers and the project management team throughout the project life cycle. Poor communication corrupt good works.

-          A strong message against deliberate re-works and wastages should be passed across to all site workers and tied to their wages so that they can apply more caution at work.

-          All working drawing should be read together during construction. No one drawing or specification should be read in isolation of the other.

-          Construction permits should be secured on time to avoid preventable actions (demolition) by relevant government agencies. 

-          Only construction materials that meet specifications for the work should be allowed to be offloaded and stored on site. All materials entering the site should be properly checked so as to avoid re-works influenced by the use of sub-standard materials.

-          Unskilled workers (labour) should not be allowed to carry out works meant for skilled workers. Similarly, avoid the use of non-trade tested artisans for works meant for trade-tested persons.



-           Site supervisors should ensure that they keep an eye on activities on site as it progresses from stage to stage and give very clear and specific instructions and directives to the workers at all times. They should also pay attention to details; ensuring that only the right tools and equipments are used for work and only the adequate quantity of materials needed to complete an item of work is provided or released from the store to curb wastages and theft.

-          Site disputes should be managed properly such that it does not degenerate into a situation that can provoke any act of malicious damage to work already done.

With all these and many more, wastage and re-works would be reduced drastically on sites and project cost and time would be saved.