Production of a good quality building depends among other variables the construction methodologies, project quality management plan and project health and safety plan. Achievement of the quality management plan depends largely on a checklist document to guide on the workmanship, construction material, inspection, material sampling and testing. 62 variables were considered as important parameters that constitute the checklist document. The 62 variables were grouped under 8 sub–headings namely subsurface, timber, formwork, concrete work, steel reinforcement, block work, rendering and roofing. Assessment was done a Likert 5 point scale and was analyzed using weighted average mean index (I_imp) which ranged from –2 to 2. The subsurface sub–sector ranked first with a mean score of 1.5752 followed by the roofing sub–sector. The least is block work with a mean score of 1.3297 followed by the rendering sub–sector with a mean score of 1.3492. Out of the 900 copies of structured questionnaires administered, 730 responded which is a return rate of 81.1 percent. The building professional bodies and all levels of the government regulatory agencies to provide quality control checklist and approved system for building project monitoring.

Keywords: checklist, quality control, mean score, building, inspection, quality planning

Complexity of building design, modern construction materials/components, construction methodologies have called for specialization in building production. It is the need for specialization and its accrued benefits, among other things that brought about the building profession worldwide. The direct benefits to clients and developers in engaging specialist include adoption of appropriate construction methodology for optimal cost, optimum production time and achieving the specified quality standards at first attempt. The construction manager prepares the production management documents like construction methodology, construction programme, project quality management plan, project health and safety plan, information requirement schedule.^1–4 It is the construction methodology that dictates the details of project quality management plan which would be used to achieve the specified quality standards.

Hackett et al (2006) stated that routine site visits are made for main reasons;

1. Checking that quality of completed work conforms to agreed quality standard,
2. Checking that the contractor’s process conforms to the programme,
3. Checking that designs are being completed according to plan.

The checklist documents include the following items:

1. Drawings and schedules,
2. Specifications,
3. Bill of quantities,
4. Quality manual for construction method,
5. Quality manuals for construction materials,
6. Products supplier’s details,
7. Sub–contractors details.

It is unbelievable that since 1960 when Nigeria gained political independence, the national standards and codes with respect to construction practice are yet to improve indigenous practice. Most Nigerian building professionals do not talk of Nigerian Industrial Standards (NIS). The standards in use do not reflect the prevailing local climate conditions which are critical to the properties of materials. The quality of these construction materials can only be guaranteed through adequate quality control inspection, material sampling and testing and by ensuring adequate storage. According to Ali and Rahmat, in the construction industry the emphasis of quality is on the ability to conform to established requirements. They identified the important criteria for measuring quality performance to include compliance with the use of specified quality of workmanship; standardized production processes to ensure quality; magnitude of quality degradation of output and above all client/customer satisfaction.^5–9 Dimeji is of the opinion that a checklist is a structured tool, usually item specific, used to verify that a set of required steps has been performed. Checklist may be simple or complex and many organizations have standardized checklist available to ensure consistency in frequently performed task. In some application areas, checklists are also available from professional associations or commercial providers. The high incidence of building collapse in Nigeria and the non compliant to quality management standard in the building industry is the yawning need of this research in South–eastern states of Nigeria. The objective of this work will be by ascertaining the level of compliance with existing quality management standards in public building projects in the South–eastern states of Nigeria in accordance with NIOB/NBC quality checklist. It will also identify and rank in order of preponderance of the constituents of quality management checklist in the South–eastern states of Nigerian.^10–11

62 variables were considered to be important parameters and constitute the checklist document extracted from the Shell Petroleum Development Company Ltd building project document. The 62 variables were listed under eight subheadings. They subheadings include subsurface, timber, formwork, concrete work, steel reinforcement, block work, rendering and roofing. The Likert 5–point scaled questions were used in the assessment of indices of preponderance and implementation of building project quality control checklist obtained from Shell Petroleum Development Nigeria Limited, Civil/Building quality control/assurance checklist. The questionnaire for this study was designed with due regard for the suggestions on question sequence and question formulation and wordings. The research adopted the structured questionnaire method. The Likert 5 point weighting were as follows: very high as 2, high as 1, undecided as 0, low as –1 and very low as –2. Respondents were required to rank the degree of preponderance on a Likert scale of 5 on the 62 variables grouped into 8 sub–headings. A survey research design was adopted in this research work. The data were obtained from research participants through a structural questionnaire, personal interviews and observations. The major actors in the population include architects, engineers, builders, quantity surveyors, contractors, clients and financiers of public buildings projects. 900 copies of the questionnaires were distributed in the South–eastern states of Nigeria namely; Abia, Anambra, Ebonyi, Enugu and Imo state. Research assistants were used in the distribution of the questionnaire across the states. Percentages were used to simplify numbers, reducing all of them to a 0 to 100 range. In the comparison of factors, the higher the percentage rating, the higher on the comparatively more significant the importance attached to the factor. Mean Score. Scores or numerical values were assigned to each of the statement that describes a situation being investigated in order to measure the intensity of agreement by the respondent to the statement. The mean score for each item was then determined from the scores and the frequency of responses for each score. The Mean Score (M.S) is mathematically represented as

M.S is the mean score

a= the respective weighting of the factors

x=the number of respondent for each weighting

N=the total number of respondents.

∑=Capital Greek sigma which means summation i.e. the sum of

The weighted average formula was used in assessing respondents ranking of importance. The weighted average for each of the variables was obtained from the sum of the product of the proportion of the responses received from each group compared to the total number of receipts (ⁿ/_N) and the corresponding mean score of that group in respect of individual variable. The weighted average is given as:

Nine hundred copies of the questionnaires were distributed to the building project professionals in the South–eastern states of Nigeria. Seven hundred and thirty responded to the questionnaires representing 81.1 percent of the respondents. Source: Author’s fieldwork. The data in Table 1 shows that 75.1 percent of the respondents were either in the consultancy or contracting organisations of the building sub–sector and therefore the background information supplied to them was deemed adequate and reliable Table 2. The data in Table 2 shows the 62 variables grouped under the eight sub–headings. The information in Table 2 was analyzed using percentages to reduce the number of respondent from 0 to 100 in each of the variables. The mean score for each variable was calculated for each of the states; namely Abia, Anambra, Ebonyi, Enugu and Imo state. The data in Table 2 were further analyzed to establish the level of awareness to quality control checklist. Table 3 is a summary of Table 2 showing the composition of the checklist sub–sector and their ranking. The information shows the eight sub–sectors, the weighted mean score and the ranking. Source: Author’s Fieldwork. It may be surprising to non–professionals that the importance of block work in building project quality management checklist parameters ranked last among the eight sectors examined. To them, it is the block work that strikes them as the most important sector. However, professionals may not be surprise that the subsurface sector ranked first. This is because they know that for the stability and durability of any building, it is paramount that the sub–surface sector is solidly fortified. While the non–professionals are interested in aesthetics of the building, the professionals are interested in the functionality of the building. The foundation remains below the ground level, the signs of failure of foundation are not noticeable till it has already affected the building. Therefore, a foundation should be sufficiently strong to prevent excessive settlement as well as unequal settlement. Unequal settlement or differential settlement may be caused by:

1. weak sub–soils such as made up ground;
2. shrinkable and expensive soils (such as clay);
3. movement of ground water and uplift pressure; and
4. Excessive vibrations, due to traffic, machinery, etc.

According to Punmia and Jain when designing the foundation the factors listed above must be taken into account.   It is not surprising that the roofing sub–sector ranked second with a mean score of 1.5672. The roof is the uppermost part of the building, provided as a structural covering to protect the building from weather (rain, sun and wind). The roof type depends upon the shape or plan of the building and the type of constructional materials. Its second position in ranking could be attributed to its value to the aesthetic nature of the building and the ability of the roof structure which support the roof covering materials to have adequate strength and stability. In this roofing subsector, rafters and purloins adequately maintain roof profiles ranked first followed by slopes and falls of roof frame of designed angle/profile. This could be attributed to the inclined members running from the ridge to the eaves. It is expressed either in terms of degrees (angle) or as a ratio of rise to span. The formwork assemblage sub–sector ranked third with a mean score of 1.5498. When the concrete has reached a certain required strength, the shutter is no longer needed and is removed. The operation of removing the formwork is commonly known as stripping. When the striking or stripping takes place, the components of formwork are removed and then re–used for other elements of the building structure. The re–use nature of the formwork material might be the reason for respondents ranking material resistant to action of cement and water as first, followed by joint being sufficiently tight to prevent leakage of grout and the formation of honeycombs or other defects. The least in the formwork sub–sector ranking is striking of formwork carried out after the specified time has elapsed which ranges from 24 hours to 21 days depending on the span and nature of the structural element and the location of the formwork in the building. The fourth in the ranking order is the concrete work sub–sector with a mean score of 1.5085. The concrete is a product obtained artificially by hardening of the mixture of cement, fine aggregate, coarse aggregates and water in predetermined proportions. Concrete has enough strength in compression, but has little strength in tension. The predetermined proportion called mix design was ranked first in the concrete sector with a mean score of 1.5948, while the workability of the concrete (slump test) was ranked second with mean score of 1.5927. In its simplest form, the term workability may be defined as the ease with which concrete may be mixed, handled, transported, placed in position and compacted. The third in terms of ranking of the concrete sub–sector is method of measuring out (batching) materials as specified with a weighted average mean score of 1.5786. It is preferable to measure cement in terms of its weight and not in terms of volume. The volume of cement changes with the conditions of measurement. In Nigeria, cement is supplied in bags, each bag weighing 50kg. Under normal conditions, the volume of cement in the bag is considered equivalent to 0.035m³. Fine aggregates (sand) may be measured by weight for accurate works and by volume for ordinary works. However, when dry sand absorbs water from atmosphere, or when water is mixed to it artificially, its volume increases. There is no problem of bulking in coarse aggregate and hence it may be measured either by volume or by weight. The timber sector ranked fifth with a mean score of 1.5034. The top in the indices of timber is timber properly seasoned and treated with mean score of 1.6631, followed by timber planks within specified dimensions and tolerance and the third, timber without defects with mean scores of 1.6354 and 1.621 respectively. Defects affect the quality, reduce the quantity of useful timber, reduce the strength, spoil the appearance and contributes to its decay. With scientific development, timber may be seasoned and treated before using it in construction work. It is easily convertible to any size and shape. Its different components may be easily jointed together to build a composite part of the structure. Its life span may be increased by proper seasoning and treatment of their surface. Steel reinforcement sector has a mean score of 1.4992 to rank sixth. Building failure is the resultant negative difference between achieved result in building structure and the expected performance. In the checklist for steel reinforcement, concrete cover to reinforcement as specified was the least with a mean score of 1.304. Coming behind steel reinforcement is cut and bent cold with a mean score of 1.399. The roles of the building professionals with respect to the use of reinforcement in concrete are complementary and awareness level in this regard should be improved because the structural engineers incorporate all these elements including concrete cover to reinforcement in his structural analysis and design. The seventh item in the ranking is rendering sector with a mean score of 1.3492. The data in Table 3 show how the professionals in the building industry perceive the procedure for the rendering operation. Apart from the decorative effect, rendering conceal inferior materials or defective workmanship and protect surfaces against termite. It can be applied to walls, columns, ceilings and other building components with this coat of plastic mortars to form a smooth durable surface. Block work had a mean score of 1.3297 to rank 8 in the items considered in this study. Among the items involved in the block work, setting out of block work ranked first, followed by block work properly aligned vertically and horizontally with a mean score of 1.3913. To non–professionals, the two items ranked 1^st and 2^nd are the most critical aspects of the block work without taking other elements and activities into consideration as outlined in the block work. While these other elements add to the structural stability of the building, block work is normally used for the construction of foundations, walls, columns and other similar structural components of buildings. The areas of low awareness on block work include metal ties for block work, block work properly tied to structural frames, quality of mortar, block work adequately wetted with fresh water before laying, bonding of blocks and sandcrete samples taken and cast into cubes.

1. Preparation of a quality control checklist and approval system for monitoring quality control indices of building project is a necessity.
2. Town planning and development control authorities and other quality regulatory bodies in the building construction industry should be more proactive in quality control programmes.
3. Efforts should be made by the Nigerian Standard Organisation (SON) and the built environment professional bodies to establish authentic standards relevant and appropriate to local conditions in all aspects of building production.
4. The building professional bodies NIA, NIQS, NSE, NIOB, etc and all levels of the government regulatory agencies to provide quality control checklist and approval system for building project monitoring using the developed quality management framework.

This research has shown that quality assurance in building project can be achieved by strict adherence to building project quality control checklist indices. The research indicated that even with drawings provided and material specifications given, quality control checklist and its usage were low among the built environment professionals. Building professional bodies to provide quality control checklist and approval system for building project monitoring using the developed quality management framework.

None.

The author declares there is no conflicts of interest.

1. Abdulkareem, Adeoti. Quality control compliance in the Nigerian construction industry: A case study of projects in Illorin. Kwara State. 2010.
2. Akpedeye, Mnoli. An overview of project management. Compulsory refresher course for prospective NSE corporate members. Abuja. Nigeria. 2016.
3. Dennis L. Project Management (7th ed), London. Gower Publishing. 2002.
4. Dimeji F. Basic concepts of quality management system and ISO 9001 standard. Paper Presented at the 13th Annual Conference of the Nigerian Institute of Building (NIOB). Lagos. 2001.
5. Ekpekurede CN. Shell petroleum development company limited civil quality control/assurance checklist – update. Port Harcourt. 2010.
6. Hackett. In the Aqua Group Guide to Procurement, tendering and contract administration. Blackwell publishing Davis London. 2006.
7. Idike CE, Agunwamba JC. Quality management in construction, De–Adroit Innovation Enugu. 2011.
8. Mincks WR, Johnston H. Construction jobsite management. USA. 2011.
9. National Building Code. Federal Republic of Nigeria. Lexis Nexis Butterworthe. 2006.
10. Opara HE. A Framework for Effective Quality Management of Public building Projects in South–eastern states of Nigeria. 2014.
11. Pepple A. Experts hail national building code for built industry. Daily Sun Newspaper. 2013