- BACKGROUND TO THE STUDY
Building, civil engineering and heavy engineering projects are major contributions from the construction industry to national development. Buildings occupy the central focus of any infrastructural development and it is constructed to basically provide the citizenry with safe and comfortable enclosure for abode, business and industrial activitiesin enclosures free from the vagaries of the open environment” (Amobi, 2009). Emmitt et al, (2005) further highlighted the basic requirement and performance of a building to accomplish the following:
- i) Adaptable and durable;
ii) Ease of maintenance (periodic repair and replacement);
iii) Ability to recycle materials and components.
iv) Thermal and acoustic performance;
- v) Service life of the building and its elements;;
- vi) Availability of materials;
vii) Sequence of construction and tolerance
viii) Reduction in waste (labour, material and time).
The building culture of pre-independence Nigeria was an absolute dependence on earth building techniques such as use of adobe bricks (sun-dried bricks) and wattle and daub (mud wall construction) Alagbe 2011. After the independence the craving for westernization resulted in the import the Conventional Building System (CBS). This system according to Benfield, (2010) implies construction with the use of in-situ masonry for the outside walls (blocks, bricks, stones and concrete walls or other ‘in-situ’ materials). Its heavily dependence on the use of cement and other imported building materials for its construction and maintenance in recent times have been proven to be inefficient and wasteful due to enormous amount of resources consumed (Ghosh 2002).
Although a number of factors attributed to the CBS as opined by Fasakin and Ogunsemi (2003) which include, “high transportation costs of materials, uncontrollable prices of building materials particularly related to the over dependency on imported building materials that is constantly subject to inflation” till date, it is still the most employed system in Nigeria.
Studies show that the environmental impact assessment carried out on the processes involved in the CBS has revealed high environmental, social and economic degradation, such as the frequent carbon emissions from construction processes, which is one of the main causes of thinning of the ozone layer and green house warming of the earth as one of the main reasons the innovative building system was introduced. To improve on the environment, innovations on sustainability by the introduction of energy efficient building materials and processes was promoted by some regulatory councils such as the World Green Building Council (WGBC), German Sustainable Building Council, Green Building Council of South Africa (GBCSA), US Leadership in Environmental and Energy Design (LEED) amongst others.
Sustainable construction was evolved as a means to contribute towards creating a healthy environment for the future. This relates to both interior and exterior environments and starts with buildings that are energy efficient.According to R.S. Means (2011), sustainable construction is such which ensures that the need of the present is met, without compromising the ability of future generation to meet its own needs. Emphasizes is drawn to the design and production of buildings without affecting the inhabitants or destroying the environment.Thus, the rational is the use of natural resources and appropriate technology
Innovative Building System (InBS) embodies sustainable buildings also called Green buildings. The process starts from the siting to design, construction, operation, maintenance, renovation, and demolition of the building, according to Yan ji (2006). It is a structure that is environmentally responsible and resource-efficient throughout the building’s life-cycle. “A building which adopts the best practices of environmental technology for optimizing the use of natural resources for providing clean and cost effective working ambience is known as Green building” (Jain, 2009) .The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort USEPA (2009). Earth Construction Technology (ECT), such as Hydraform interlocking blocks (South Africa), latcem/ latform panels made popular by Okereke (2002); Energy Automated System buildings (e.g. Minerge), in in-situ and prefabricated technology to mention a few are all a form of the Green building concept of InBS (Jain, 2009 and Okereke 2003).
While the practices, or technologies, employed in sustainable buildings are constantly evolving and may differ from region to region, fundamental principles persist from which the method is derived, such as: Siting and Structure Design Efficiency, Energy Efficiency, Water Efficiency, Materials Efficiency, Indoor Environmental Quality Enhancement, Operations and Maintenance Optimization, and Waste and Toxics Reduction. The essence of green building is the optimization of one or more of these principles. Thus, it includes the rational use of natural resources and appropriate management of the building assets, contributing towards the reduction of energy consumption, and damage to natural and social environment (WBDG 2009; USEPA 2010; Ashworth, 2006).
More than half of the sub-themes in the 3rd Architects Colloquium in 2010 and the Archibuilt 2010 organized in the capital city Abuja, were dedicated to maintenance and materials policy for sustainable infrastructural development, global warming and green architecture (Prucnal-Ogunsote, 2010). This implies that the building industry in Nigeria hasrealised the need to promote this global initiative. One of the objectives is to move towards innovative construction in Nigeria so as to improve the quality and quantity of housing needs without endangering the construction environment.
While some developing countries like South Africa, Sudan, Ethiopia, Rwanda, Zambia, Kenya, Tanzania amongst many have adopted the sustainable building approach using earth construction technology to solve mass housing demand in their countries, (Agrement South Africa 2010), Nigeria is still struggling to meet her housing deficit estimated at above 17 million housing units as at 2007 (M.L.U.D., 2007) relying mainly on the conventional wet system of sandcreteblocklaying in cement-sand mortar.
According to Adedeji, (2007; 2008) the Nigerian Building and Road Research Institute (NBRRI) launched the interlocking masonry into a commercial level as far back as 2002 as an alternative masonry material to the conventional types. It was evolved as a strategic approach to mass urban housing prototype for housing delivery, and an engine of growth in the developing Nigerian economy. It failed however to gain the popularity needed for massive construction because of the constraints of acceptance by many on the excuse of poor quality and cost ineffectiveness.
Several authors and researchers both foreign and indigenous have found various advantages of this system in terms of quality, performance and cost. How truethis is,remains the major question or challenge faced by every Nigerian government, private and the common man. How much? What difference in cost to the existing system? It is no wonder that Real Estate Developers (RED) have not found it worthwhile to deploy their resources in the system because of the lack of adequate knowledge of the actual or estimated cost of its construction and maintenance.
Costing of InBS in Nigeria is still fallow in the areas of measurement and costing standards. According to RSMeans (2011), evaluating the cost of production can be achieved by examining costelements and the technology employed in terms of materials, labour and plants. The following constitute the interrelated cost elements to be evaluated:
- Initial cost in terms of design;
- Cost –in-use;
- Construction cost (cost of materials, Plant and labour).
This study seeks to examine and evaluate the cost economics involved in the production of InBS and compare it with the existing cost standard of the CBS. The findings from the study will determine whether or not the InBS is of cost advantage over the CBS and to what extent it will aid sustainable construction and mass housing supply to the populace.
- STATEMENT OF THE PROBLEM
The general lack of purchasing power is a factor that has contributed to the progressive deterioration of the housing situation in developing economies (Arumala et al, 2007).The poverty level in Nigeria has made it difficult for many to own houses since land and construction costs are mostly beyond their means. Only a salary earner at a grade level above 13 in the Nigerian Federal Civil Service can afford a property cost of N4.75 million on a 25 year mortgage at 6%, if he devotes 50% of his salary per annum to housing (Daramola et al, 2005; Onyike, 2007).
The rising cost of conventional method of construction has not made it any easier. To meet the ever-growing demand on housing, the country needs ten times more or at least 100,000 new housing units annually (Adejumo, 2009). How and when then can affordable housing be achievable by all?
Regrettably, Nigeria is faced not only with the problems of housing as regards to quantity, but also the poor quality of available housing units (Nkah, 2009). With the introduction of carbon metric by the World Green Building Council (WGBC) for accessing quality buildings in Nigeria, many existing buildings may not meet up with the specified minimum requirements.
Despite the recent breaking of new grounds, developers still find it difficult to opt for sustainable buildings due to price constraints, difficulty in sourcing green building materials, necessary technologies and service providers or facilitators (Roy et al 2008). Existing practice manuals in Nigeria show the lack of relevant data on productivity constants, costing, specification and measurement standards, required to build rates for InBS. This is evident from the Building and Engineering Standard Method of Measurement (BESMM3 2008), standard method of resource scheduling (2006) and Nigerian Building Price Book amongst others. The lack of standard national code of practice in the country is also a major setback, so also the absence of reliable national standards established from years of research on existing local conditions, such as prevailing climatic conditions in the various climatic zones in the country (Okereke, 1988). This has made costing of not only CBS, but more so InBS difficult. The following existing and prevailing problems have motivated the research:
- Environmental degradation due to construction activities;
- High cost of project delivery due to risingcost of building construction and maintenance ;
- Growing deficit in housing supply forcing a higher number of Nigerians to live in either substandard or sub-human accommodation;
- Poor investment returns on large capital outlay on buildings, thereby discouraging many foreign and private investors;
- High tenancy rate due to high demand for available buildings and investment recovery;
- Few housing units obtainable from huge capital release by government;
- Inability to estimate resources requirement in terms of labour, materials and plants necessary for construction and maintenance of the system has limited the ability of professionals to produce accurate tenders, reliable contract documents and appropriate scheduling for project execution of InBS
- The high cost of expatriate assistance has discouraged the common Nigerian to see advantages in the InBS system.
It becomes imperative therefore due to the research gaps, to evolve an appropriate technique that will incorporate peculiarities inherent in InBS for efficient and effective evaluation of construction processesfor the purpose of costing of the projects. Based on this, cost comparison of the two systems can be carried out to evaluate cost efficiency and value difference which will form a yardstick for promoting the massive adoption of the system. Achieving this is the main focus of the study.
1.3 AIM AND OBJECTIVES OF STUDY
The aim of this study is to create awareness to stakeholders in the built-environment, onthe cost effectiveness and other potentials of InBS as a sustainable alternative to the CBS in South- East Nigeria, and by show casing its applicability in some buildings in the study area.
To achieve the aim above, the following objectives will be carried out:
- To explain the concept of sustainability in the use of InBS in housing;
- To compare the materials and labour requirements in the two systems
- To appraise the level of awareness of building professionals and real estate developers on the potentials of InBS in the south-east states of Nigeria;
- To evaluate the cost elements in InBS in terms oflabour, materials, plants and organizational requirements;
- To proffer applicable recommendations towards greater awareness of the benefits of InBS.
1.4 RESEARCH QUESTIONS
The study will seek to give answers to the following research questions:
- Is the use of InBS popular in the south-eaststatesof Nigeria in solving the housing problem?
- To what extent can the use of InBS for buildings increase the housing stock in Nigeria?
- Is there any significant cost difference between InBS as against CBS?
1.5 SCOPE AND LIMITATION OF STUDY
This study will focus on the evaluation of cost of materials and labour used in the constructionprocesses of load-bearing components of Innovative Building System in residential and public buildings. It will seek to use this to compare the cost of labour and materials with those of Conventional Building System.
Thethe study will be limited to building projects executed in South East Nigeria, in which innovative walling systems such as Hydraform and latcem panels were used. This is due to the similarity in the soil type, socio economic and climatic factors in the region and the availability of data needed to support the systems chosen.
Other factors which limit the scope and geographical coverage of this study are time and cost constraints as well as the limited data available generally in Nigeria building sub-sector on InBS.
1.6 JUSTIFICATION OF STUDY
This research will contribute immensely to reducing drastically the problems of affordability, adequacy and sustainability in housing provision in Nigeria.
It is geared towards providing the professionals, especially builders and quantity surveyors as well as developers in the Nigerian construction industry with adequateknowledge of cost effectiveness and other potentials of InBS. It will also help in decision making by potential house owners and developers as an alternative housing system.
It will also help to promote increased awareness of the InBS as a sustainable building system and its cost benefits to individuals, private investors and government.Finally, it will become a workable guide for further research on InBS in Nigeria.
1.7 DEFINITION OF TERMS
The following terms are defined to enable clarity as these will be frequently used in the course of this research:
- Construction: refers to all type of activities usually associated with the erection and repair of immobile facilities.
- Construction industry: as opined by online business dictionary, (2010) it is the sector of the national economy engaged in the preparation of land and construction, alteration and repair of building structures and other real property.
- Innovative buildings: this can then be said to be innovation of existing building system by introducing smart/intelligent – environmentally responsive, cost effective in construction and ease of maintenance (Jain, 2009).
- Conventional: A traditional method using usual practices of accepted standards which have been time honored unimaginative and a common routine (Scrib, 2011).
- Hydraform building system: This is a rapid building system which combines innovative and conventional building system with the use of compressed earth block technology.
- Cost: this is the amount required for the payment or expenditure for an asset related to time, labour and material for the attainment of a goal.
- Cost evaluation: an opinion or assessment of cost in terms of the quality and value of the project under careful study.
- Sustainable materials: materials with overall superior performance in terms of local production, limited transport cost, thermal efficiency, health considerations, financial viability and environmental impact.
- Cost in use: this a form of modeling technique to cope with the mixture of capital and running cost of a project.
- Building: a structure built for human habitation with roof and walls such as house or factory.
- Green buildings:Green building (also known as green construction or sustainable building) refers to a structure using process that is environmentally responsible and resource-efficient throughout a building’s life-cycle: from conception to design, construction, operation, maintenance, renovation, and demolition.
- Construction process: A set of inter-related and sequentially connected activities, operations or manipulations, which result in the accomplishment of complete or partial building production.
1.7 STUDY AREA
1.7.1 Geographical Location
According to Igbokwe (2007), South-East region is located between latitudes 040 30’N and 070 30’N and longitude 060 45’É and 080 45’E. The study area comprises the geographical location of the following states: Abia,Anambra, Ebonyi, Enugu and Imo. The region is bounded in the north-west by Kogi and Benue States, in the north-east by Cross River State, in the South by AkwaIbom and Rivers States and in the west by Delta State as shown in Figure 1.1. The area is well drained. The notable rivers and streams that are found in the zone include the Niger, Cross, Imo, Nike Lake, Anambra, Idemili, Njaba, Oguta Lake, Nkisi, Esu, Oji, Ebonyi, etc. These States have fairly good sub-soil strata except Ebonyi which shows clay stratification. Enugu state exhibits a coal sub strata but with gravelly laterite to topsoil up to a depth of about 5 meters. Anambra, Abia and Imo States exhibit quality sub-base foundation soil for buildings and other construction work.
1.7.2 Climatic Characteristics of the South-East Nigeria
The area lies within the tropical region with early rainfall usually in January/February and full commencement of the rainy season in March, ending in November of each year. The dry season lasts between four to five months. The highest rainfall is recorded from July to October (4 months) with a little break in August. The average highest annual rainfall is about 1952 millimeters (Okereke, 2008).
The temperature, rainfall and relative humidity patterns show that the daily and annual values are moderate, high and constant respectively. The temperature ranges between 26 to 320C with annual mean of about 290C, while relative humidity is 70 to 82%, and rainfall intensity is 1157mm to 2600mm/hour. The nature of climatic variations associated with the weather in the study area shown in Table 1.1
Table 1.1: Climatic conditions variation in the area
|Rainfall intensity (mm)
|Rainfall duration (days)
|Relative Humidity (%)
Source: NMA, 2012
Prevailing climatic events, such as temperature, rainfall, high winds and humidity have some consequences in the production of concrete work on construction sites. Planning for these weather-related emergencies, in the design and method of production will rely on knowledge of the frequency of these events (Okonkwo andMbajiogu, 2010).
The assessment of the precipitation is an important problem in hydrologic risk as far as concrete production is concerned. This is why the evaluation of rainfall extremes, as embodied in the intensity-duration frequency (IDF) relationship, has been a major focus of both theoretical and applied hydrology (Andreas and Venziano, 2006). Dupont et al, (2000) defined rainfall IDF relationships as graphical representations of the amount of water that falls within a given period of time. These graphs are used to determine when a certain rainfall rate or specific volume of flow will reoccur in the year.
Smith (1993) stated that the precipitation frequency is determined by the amount of precipitation falling over a given period in a year. From Figure 1.2 shows the map of member states of the south-eastern geographical region while Figure 1.3 shows the months in which the highest rainfall occurs within the study area.
Annual temperature and rainfall total vary widely from year to year and across the area. The distribution of the mean annual rainfall in the area is as shown in Fig. 1.3. It reveals that the highest mean annual rainfall of 2380mm occurred at Owerri while the lowest of 1860mm occurred in Enugu. The month at which the peak of the monthly rainfall occurs varies from one part of the country to another (Ayoade, 1975). The areas covered by this data have highest daily rainfall in the month of July through September.
|Figure: 1.2 Map of South-East Nigeria Showing the five states
Source: Department of Surveying, MLHS&UD IMO STATE
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