Owner and Contractor Perceptions Toward Factors Causing Delays in Structural and Finishing

A construction project comprises of a number of work packages, which are subjected to delays. These delays may be caused by many on-site factors. The aim of this research is to represent owner and contractors perceptions towards delay factors that frequently occur in structural and finishing works. Data for analysis were gathered by distributing questionnaire. A total of 198 sets of questionnaire were gathered and used for subsequent analyses. In general, design changes during construction are perceived by respondents as the most frequent factor to cause delay in all structural and finishing works. The results also show that there are a number of differences between owner’s and contractor’s perceptions towards the occurrences of the factors. Whilst most contractors concern that information factors related to project design and scope frequently causing delays in construction works, owners consider many contractor originated factors, as most frequent delay causes.


Introduction
Construction possesses unique characteristics compared to other industries.It can be said even, that each project is different from each other, by presenting different problems during the construction process.Design and execution processes under time pressure and limited budget, labor oriented works with temporary assignment, and many change orders involved are few characteristics that may describe its uniqueness [1].Due this, without appropriate plan and control, construction projects completion can easily slip from their original plan.In other words, delay will easily happen.Longer project completion will absolutely then cause cost overruns and may influence the reputation of the project participants.
For appropriate plan and control, it is thus important to understand what factors frequently cause delay during the construction stage.Further, it will be more valuable to signify factors that cause delays in different construction work packages from the perspectives of the owners and contractors.This paper intends to attain this objective.

Delay Factors in Construction Works
In construction claims, a delay can be described as the time during which some part of the construction project has been extended or not performed due to unanticipated circumstance [2].
An incident of delay may be caused by any factor that influences the construction project, which will be described in the followings.

Delay Factors
Based on the actor, delay may be caused by the contractor, the owner, the designers, other prime contractors, subcontractors, suppliers, labor unions, utility companies, nature, or any number of other organizations and entities, which participate in the construction process [3].This paper focuses on factors at project level that may occur during the construction stage.Others at more macro level, such as political, social, economical, and law factors are beyond the scope of the study.
After reviewing a number of previous related works [4−9], this paper collected forty-three site related factors causing delay, which were grouped into seven categories, i.e. labor, site characteristics, information, material, equipment, managerial and other factors, as seen in Table 1.Detail explanations for each delay factor can be obtained from Lalitan and Loanata [10].

Construction Works
In general, a building project comprises of five work packages, i.e. preliminary, structural, finishing (architectural), MEP, and sanitary works, in which each may have special characteristics.Therefore attempts to generalize important factors causing delays to all work packages, as most studies cited above did, may have limited value.Since each construction stage may pose specific delay factors.It thus may demand different approach in mitigating them.
The current study focuses only on structural and finishing work packages.The structural work is subpackaged into three packages, i.e. lower structure (e.g.foundation and basement), upper structure (e.g.concreting of beam, slab, column structures and steel works) and roofing works (e.g.roof truss and roof tile).Meanwhile the finishing works are subpackaged into five packages, i.e. floor finishing (e.g.floor tiles), interior masonry, exterior masonry (e.g.brick walls and plastering), interior wall finishing, exterior wall finishing (e.g.painting and doors and windows), and ceiling works (e.g.gypsum, painting).Readers are referred to [9] for more information about the work packages

Research Method
The study employed questionnaire survey method to gather the required data.The targeted respondents were contractors and owners.The questionnaire consisted of three major parts, i.e. general information, frequency of occurrences of the delay factors listed in Table 1, and time impact if the delay occurred.This paper will discuss only the results of the first and second part.For the purpose of the study, the respondents were required to indicate whether a specific delay factor often occurred in a specific construction work package (if any) by choosing the designated boxes.Table 2 presents an example of the questionnaire in structural works.There, for each delay factor, respondents may choose one or more, or none of the work packages.For example in Table 2, a respondent perceives "labor shortage" frequently occur in lower and upper structural work packages.The complete questionnaire can be gathered from [10].Frequency analysis of delay factors was performed for each work package by calculating the number of respondents (in percentage) selecting the factor.A cut off point of 75% was taken to decide whether the occurrence of an on-site delay factor is frequent or not.For the purpose of comparison, frequency analyses were carried out for different types of respondents, i.e. owner and contractor, for each work package and also overall structural and finishing packages.

General Information
A total of 198 respondents, consisting of 160 contractors (81%) and 38 owners (19%), participated in the survey.Most owners and contractors had experiences in more than one type of projects.However, the types of project mostly experienced by the respondents were building and medium to high class residential projects.About 82% and 78% of the owner and contractor respondents, respectively, experienced in building type of project.Table 3 exhibits more general information about the respondents.

Delay Factors in Structural Works
Table 4 presents the frequency of occurrence (in percentage) of delay factors in each structural work packages perceived by both owners and contractors.The shaded boxes highlight the factors that frequently occur in a specific structural works (indicated by the percentage value of 75% or more).Meanwhile the overall frequency and its respective rank for structural work packages are exhibited in Table 5.

Contractors Perceptions toward Delay Factors in Structural Works
According to the contractors, there are nine delay factors that frequently occur.The followings are the factors in each work package (Table 4).Considering the overall frequency (Table 5), two factors are considered by the contractor to frequently occur in overall structural works.They are: • design changes during construction (87.50%) • slow shop drawing approval (87.29%)

Owners Perceptions toward Delay Factors in Structural Works
Meanwhile as perceived by the owners, there are twenty factors, which frequently cause delay to structural works.The followings are the factors in each structural work package (Table 4).For the overall structural works (Table 5), the owners perceive three frequent factors.They are: • slow payment to contractors (80.70%) • design changes during construction (78.07%) • force majeure (75.44%)

Discussions
Both owners and contractors agree that many factors related to construction site (site characteristics factors) frequently cause delays in substructure works, which may include excavation, piling and raft foundation works.Without proper planning and preparation, the construction of deep basement and deep foundation would easily be delayed by heavy rain, which usually generates flooded area.
As for the contractors, they consider information related factors as the most frequent causes of delay in almost all structural works.The information may include changes in design, scope and shop drawings.
The results are in line with the previous findings in Indonesia and other countries, which reported design related risks as critical and major sources of construction claims and disputes [11,12,13,14,15,16].
On the other hand, owners note that slow payment to contractor is the most frequent cause of construction delay in all structural works.The owners realize that without timely payment, contractors may not be able or may not want to continue their works, especially for those contractors with limited capital.The owners, as indicated in Table 4, also point out many material factors (e.g.availability and quality) as delay causes, especially in upper structure works, whilst the contractors did not.
It is interesting to see that the owners disagree with the contractors regarding to the factor of slow shop drawing approval as one frequent delay cause.The owners rank the factor low (27 th ) as opposed to that of the contractors (2 nd ).In general, it can be said that the owners' perceptions were higher than the contractors' as to the frequency of contractor originated factors, such as poor site layout, inappropriate work method, insufficient material storage, and labor factors.As for the overall finishing works (Table 7), the analysis indicates two most frequent delay causes perceived by the owners, i.e.: • design changes during construction (88.16%) • labor shortage (76.32%)

Discussions
Similar to the structural works, information related factors (changes in design and scope, shop drawing) are cited by the contractors as the most frequent delay causes in all finishing works.Meanwhile the owners only agree with design changes during construction as the most frequent delay cause (ranked 1 st ).
The owners give more attentions to contractor originated factors, such as labor shortage, slow delivery of material and poor supervision (ranked 2 nd , 4 th , and 5 th respectively).They also believe in material factors as the delay causes in floor finishing works.In overall the owners place higher percentage values than the contractors for the delay factors under the contractors responsibility.

Conclusions
This paper has presented the owners' and contractors' perceptions toward on-site factors frequently causing delays in two major construction work packages, i.e. structural and finishing works, and their respective sub-work packages.The most frequent and common factors causing delays in structural and finishing works as expressed by the contractors are associated with design information.The frequent occurrences of changes in design and scope of work during construction, which are usually initiated by the owners, may indicate that attentions given to the design and planning stage are still inadequate.It will be more beneficial if the changes can be accommodated before the construction takes its place.
As a part of quality assurance program, shop drawing submitted by the contractor should be approved by owner (or its representative) before the construction works can take place.It was found that slow approval frequently occur to both work packages.To effectively reduce the problem, there should be a standard operating procedure regulating the shop drawing approval, including the time frame for submittal and review.As can be seen in the analyses above, the contractors themselves are also slow in delivery of the shop drawings.A computerized shop drawing administration system would be helpful in this case.
In structural works, factors related to site characteristics (such as bad weather, difficult site condition and poor access) have been considered by the respondents to frequently occur specifically in substructure works.In general these factors cause delay more in structural works than in finishing works.Factors related to equipment are also experienced more in structural works.This is because they utilize more equipment, such as the piling machines, excavator, mobile and tower cranes, and so on.Some differences in owners and contractors perceptions are revealed in this study.Basically the contractors consider the owners as the main source of the delay in construction works.On the other hand, the owners place many factors originated by the contractors (related to material, labor, and managerial factors) as crucial in generating delays.
It should be noted that the principal purpose of identifying the frequent delay factors is to manage them before a project starts.Accordingly, one of the most interesting and important things is the way to respond to the factors.For an example, Minato and Ashley [17] suggest that it may be more beneficial to manage common risks (delay factors) at the corporate level rather than at project level.Thus it will be beneficial if analyses are conducted to compare the delay factors in structural and finishing works.This may result in two categories of factors, namely common and specific factors.Construction personnel equipped with the knowledge of delay factors that commonly occur in construction and also specifically in individual work package may consider different strategy in dealing with the risks.The authors will present the findings in another paper.

Table 1 .
Seven Categories of Delay Factors

Table 3 .
General Information of the Respondents

Table 4 .
Frequency of Delay Factors (in Percentages) in Each Structural Work Package

Table 5 .
Frequency and Rank of Delay Factors for the Overall Structural Work

Table 6 .
Frequency of Delay Factors (in Percentages) in Each Finishing Work Packages

Table 7 .
Frequency and Rank of Delay Factors for the Overall Finishing Work Similar to the above analyses, Table 6 portrays the frequency analysis of delay factors in each finishing work packages and Table 7 for the overall finishing work.