This article examines the different types of drawings issued in construction projects. These drawings will be reviewed from a contractual perspective. Construction law is unique in that it is a blend of both legal matters and technical matters. Various documents that are typically considered ‘technical’ such as drawings, specifications, programmes etc are not reviewed by legal professionals with the same rigour as compared to ‘legal’ documents such as particular conditions, bond, guarantee, warranty etc. A legal examination of technical drawings is important because drawings are possibly one of the more common sources of contractual disputes that do not usually attract adequate legal attention. Having certain level of technical proficiency of the types of drawings, its purposes, timing of issuance, common points of contentions etc will greatly facilitate a holistic understanding of the project’s risk profile.

There are various types of drawings produced by various parties throughout a typical construction project, each with its own unique contractual implications. Even under the traditional procurement route of design-bid-build with comprehensive design in place prior to the engagement of main contractor, the main contractor or its subcontractors are still expected to produce certain types of drawings throughout the construction period. In other words, one is expected to produce drawings even when it generally does not shoulder design responsibility. Therefore, issuance of any drawings should be done with great caution for avoidance of ambiguity as regards design responsibilities. The subsequent sections of this article address different types of drawings issued chronologically throughout a typical construction lifecycle under a traditional procurement route.

Tender Drawings

Tender drawings are produced by designers engaged by the Employer to communicate the scope of works to contractors bidding for the project to facilitate pricing. Tender drawings are essential component of the Employer’s invitation to treat in order to shape the scope and nature of offers from the contractors. The tender drawings’ clarity will in turn enable provision of offers which are defined and unambiguous which then facilitates acceptance. A constant change in invitation to treat creates ambiguity in the scope of offer, which can be a recipe for contractual disaster. Indeed, one of the inherent characteristics of a construction tender is the common changes in tender drawings even before the contractors have the chance of submitting its offer, and it continues to change even after the offer is made. 

One of the reasons to the above phenomena is because the tender exercise commences even before the design is fully developed. This consequently  results in changes in scope of works during the tender period causing the issuance of revised tender drawings. Where the tender drawings are revised during the pricing period, these are ‘tender addendum drawings’. On the other hand, ‘post tender drawings’ refers to revised drawings issued after the pricing duration such as during tender interviews. These revisions could be necessitated by feedback from contractors to clarify drawing details or adopt ion of certain suggestions that enhances ‘construct-ability’ or revisions in design as part of commercial negotiations.

Whilst it is not advisable to have multiple revisions to drawings after the commencement of tender, it remains a common practice. It is important to note that there are typically multiple designers producing tender drawings including architects, structural engineers, interior designers, building facade consultants, mechanical and electrical engineers etc. Therefore, the change in one set of architectural tender drawings potentially implicates consequential revisions to tender drawings of other disciplines. Ideally, various consultants are well coordinated and move in complete locked-step in ensuring design consistency. In reality however, every change or revision in drawings increases risks as it relates to design consistency and conflicting interpretations. Occasionally, changes in design are not even appropriately reflected in revision to drawings but rather casually annotated in hand sketches, part prints etc all of which are not accompanied with the relevant details and also not drawn to scale. Ultimately, it makes the process of compilation of contract document that much harder and complex, which will be further elaborated in the next section of this article. 

Contract Drawings

Contract drawings illustrates the final scope of works agreed between the Employer and the selected contractor which are included in the construction contract document. Contract drawings formed the basis of the original contract sum. Substantively, contract drawings represent the penultimate version of tender drawings. The selected contractor’s offer is accepted by the Employer via the execution of Letter of Acceptance or Letter of Award which is known as an ‘LOA’ in short. The actual formal contract document with complete set of contract drawings are usually compiled and formalised several months after the signing of the LOA. It is important to note that the LOA itself is not accompanied by a physical set of contract drawings. The LOA merely provides a list of correspondences between the contractor and project consultants during the tender period which identifies the timing of issuance of tender drawings or any revisions thereof. In other words, this list of correspondences in the LOA sets out the ‘referencing paper trail’ of the design changes from a chronological perspective. As a result of the duration taken for the preparation of contract drawings, the initial phase of construction project may proceed for months without a physical set of contract drawings in place. This could be contractually risky as there is an absence of documentation clarity in the agreed scope of works during this period. It is not uncommon for the contractor with its tender team being separate and distinct from the project execution team. Once the tender phase is completed and the project is secured, its execution is handed over to another team with different skill set and focus. A new team without the legacy knowledge of what was the scope of agreement, coupled with the absence of physical contract drawings for a period of time may be the recipe for contractual disputes.

Although the formal contract document and contract drawings are important to properly administer the project, there are no associated compilation and formalisation deadline stipulated within the standard forms of contract. One of the time consuming aspect to the formalisation of contract drawing, is the effort to create the penultimate version of tender drawings especially if the original tender design was revised multiple times during the course of procurement and commercial negotiations. The superseded versions of tender drawings are excluded for avoidance of confusion and where necessary any hand sketches previously produced are converted into appropriate format such as the ‘computer aided design’ or CAD version. Generally each contract drawing carries a unique drawing reference which would indicate how many previous version(s) had been produced prior to its final form. 

For reasons that will be further elaborated in the next section of this article, the production of further drawings will continue even after the construction contract is concluded. These drawings are known as ‘construction drawings’. In theory these construction drawings should be substantively identical to that of the contract drawings. However it is quite common for these new drawings to include additional details. These additional details are quite common sources of dispute if the contractor believes that these amounts to variations to the agreed scope of works that give rise to entitlement to additional payment or even extensions of time. Therefore, one of the reasons why the formalisation of contract document and contract drawings can be time consuming is because the contractor’s team may review every draft contract drawings issued by the consultants. These review processes can be protracted and detail oriented as the contractor wishes to avoid inadvertent inclusion of construction drawings with supplementary details as contract drawings. Where such mistakes occur, it may well jeopardise the contractor’s entitlement to additional payment or time.

Construction Drawings

Construction drawings refers to drawings issued by the consultants to the contractor to illustrate the actual scope of works that are to be constructed on site. The contents in construction drawings may be different from contract drawings from time to time for a variety of reasons. In manufacturing industry, every item produced is virtually identical due to standardisation in the production process. By way of example, the mobile phone of a specific model from a specific brand should be no different whether you purchase it from shop A or shop B. In the construction industry however, no two buildings are completely identical even if these are designed by the same architect and build by the same contractor. This is because no two plots of land are completely identical in shape or soil condition or geographical orientation or urban zoning regulations or its neighbourhood etc. In a building design process, it is often a balance between end user requirements versus taking advantage of the inherent characteristics of the site condition. Construction of buildings are therefore often described as being “prototypical”. Whilst building designers often adopt standardisation as much as possible to increase efficiency and productivity, these are somewhat constrained by realities. Some of these realities are uncovered when the actual construction process commences where adaptation of design are required. These adaptations are required notwithstanding the best effort exercised during the conceptual design. 

Tender drawings or the subsequent contract drawings are sufficient to communicate the design details for the purposes of pricing the construction project. These drawings are however inadequate in respect of details to actually complete the construction works due its prototypical nature. Therefore after the execution of LOA, it is common for the architect and engineers to issue construction drawings to enable the contractor to carry out its construction works in accordance to the site circumstances. From time to time, these construction drawings include details that depart significantly from the contract drawings such as actual dimensions, specific choice of finishes. Under such condition, the contractor would request for an instruction from the architect, or engineer pursuant to the conditions of contract to acknowledge its entitlement to additional payment or even additional time. Some of these requests may be contentious in that the project consultants consider any differences exhibited in construction drawings are part of the contractual risks allocated to the contractor and that the prices shall be inclusive of expenditures that are indispensably necessary to complete the works. Therefore these requests for instructions are rejected resulting in disputes. Whether one is advancing or defending against such claims, it is crucial to compare the relevant construction drawings with contract drawings to appreciate the scope of works in dispute. Such disputed scope of works should be reviewed in conjunction with the relevant conditions of contract so as to determine the merit of such claims. It should be noted that the extent to which the architect or engineer issue construction drawings is dependent on the type of specifications included in the contract. In the case of performance based specification where the contractor’s obligation is to construct to achieve a stipulated outcome or requirement which is common in the domain of mechanical and electrical works, the issuance of construction drawings is considerably less. In this case, the contractor has more freedom and flexibility to dictate the choice of materials or brands of systems, as long as it fulfils the said performance specification.

Combined Services Drawings

The combined services drawing or ‘CSD’ in short is usually produced by the main contractor or mechanical and electrical (M&E) subcontractor rather than the consultant engineer. These drawings show the locations, layouts and sizes of all M&E services such as electrical cabling, ventilation ducts, fire sprinklers system, CCTV, plumbing works etc. These drawings coordinates the layout of various services from different M&E trades normally carried out by different subcontractors. The main contractor is therefore by default in the best position to execute these coordination efforts due to its supervisory role in respect of all subcontractors. The main goal of CSD is to determine the optimal layout of these services within a confined and congested space such as above false ceilings. Occasionally, certain cables or pipes are required to penetrate through structural elements such as concrete beams or slabs. Therefore the CSD illustrates the interface between architectural, structural and M&E domains. 

From a contractual perspective, it is important to note that the production of the CSD is effectively a detail design development process based on a set of objectives stipulated under the performance based specifications. Notwithstanding under the approach of design-bid-build where the contractor is expected to build based on a given design, it is in actuality a form of partial design and build. This is because the main contractor and M&E subcontractors through production of CSDs develop detail design on the routing of services based on performance based specifications. Therefore there is no pure traditional procurement approach unless the consultant M&E engineer is also responsible for production of CSD, which is rare. By way of example, the consultant engineer prescribes the capacity or performance requirement of a particular M&E trade and it is usually up to the subcontractor and the main contractor to propose systems that meet those requirements. The production of CSD is therefore part of the process to demonstrate that those requirements can be achieved based on certain proposed systems. 

There are critics who would understandably disagree and argue that the design responsibility continue to be shouldered by the consultant engineer because the proposed system is ultimately approved by the consultant engineer notwithstanding proposals made by the contractor. In this regard, it is important to examine the commonly found provisions in the standard forms of contract pertaining to any design proposals raised by the contractor. Even under the standard forms of contract for traditional procurement approach, there are provisions therein that anticipates some level of design responsibility that resides with the contractor where the choice of workmanship or material or performance of the actual works is made by the contractor. In this regard, it is important for any contractor to pay special attention to these provisions and if necessary negotiate particular conditions that is consistent with the acceptable scope of responsibility. Where there is agreement for the contractor not to shoulder any design responsibility, it is important for the corresponding CSD to exhibit the relevant disclaimers for avoidance of doubt.

Shop Drawings

The main contractor or its subcontractors are usually responsible for the  production of shop drawings. The shop drawings is in essence a graphical interpretation by the contractor of the consultant’s design of certain systems that are to be prefabricated off site by including field dimensions, installation details that were previously not available in contract drawings. There are certain building components or systems that are usually fabricated off site such as structural steel members, precast concrete units, air handling units, standby power generators etc. Prior to fabrication, the precise site dimensions are included in shop drawings for the consultant engineer’s approval. Upon approval, these shop drawings are then handed to fabricators for manufacturing based on those precise dimensions so as to avoid abortive modifications on site.

From a contractual perspective, the review and approvals of shop drawings can be a source of contractual dispute particularly if the engineer makes annotation on shop drawings that is perceived as variation from the original design. Where the installation details annotated on the shop drawings warrants additional works that goes beyond what was originally priced by the contractor in the contract sum, it can be tricky to objectively determine if those annotations indeed entitles one to additional payments. This is because the main purpose of producing shop drawings is to incorporate details that were previously not available in contract drawings. Therefore differences in contract drawings from approved shop drawings are to be expected and cannot be the sole evidence that variations were indeed instructed. Parties in such situation are advised to refer to other parts of the contract documents such as pricing schedule, preambles or specifications for further clarity. Where parties believe that certain annotations on shop drawings may give rise to contractual dispute, it would be prudent for the claimant i.e. the main contractor or subcontractor to formally request for an instruction in compliance with any condition precedents. One should not assume that annotations or hand written notes on shop drawings by the approver amounts to an instruction for change in scope of works. 

The very need to develop shop drawings, or even the CSD reinforces once again the fact that contrary to popular belief, contract drawings are sufficient for pricing but inadequate to complete the construction works. Once construction works begin, the level of details that are expected are usually higher than the information available during tender. That is why the types of drawings issued during construction project can often be a fertile ground for contractual disputes.

As Built Drawings

As built drawings are produced by the contractor upon practical completion of the construction works to illustrate the full and final completed works. It includes all variations instructed during the construction period, apart from the abortive works. These drawings can often serve as useful points of reference for parties to settle final accounts because it illustrates any changes to the original scope of works. The provision of a complete set of as built drawings is usually a condition precedent stipulated prior to final tranches of payments to the contractor, in addition to other deliverables such as warranty documents. 

Whilst on one hand it marks the completion of a construction project, as built drawings are also important if and when the next construction project commences. Assuming the completed building is subject to certain future additions and alterations works or maintenance works, the next team of design consultants will use the as built drawings as the basis of their design development. Likewise, during tender for the next project, the as built drawings are usually distributed to the contractors for their pricing reference as it relates to the scope of works required. In view of the above, the accuracy of as built drawings becomes crucial. Errors in as built drawings can cause disputes in subsequent projects. Unfortunately, during the initial production of as built drawings when the project is originally completed, its accuracy is rarely the subject of much scrutiny as it is almost inconsequential to the completed project. Fortunately there are regulations in most jurisdictions that require the full and comprehensive as built drawings to be submitted to the relevant authorities for its record and in exchange for issuance of statutory approvals. Any material inaccuracies included in these as built drawings may result in fines and penalties.

Given that as built drawings are usually due for submission by the contractor after the project is substantially completed, the question that may occasionally be raised is whether the act of requesting for as built drawings by the architect or engineer implies that the contractor’s work is deemed satisfactorily completed. This argument arises because the architect is usually required to submit a full set of as built drawings to the relevant authorities for its issuance of statutory approvals. On the other hand the architect may refuse to issue practical completion certificate to the contractor due to existence of defects or other non conforming works. In reality, it is possible for the project to be both substantially completed and for a list of defects to exist. In fact it is rare for project to be substantially completed and be literally defects free. The question for the certifier to decide impartially is whether those outstanding works are indeed acceptable defects as defined under the contract or was it so significant that there is a delay to completion. This issue in turn raises the question of how practical completion is defined under the construction contract in hand. From the main contractor’s perspective however, the as built drawing should illustrate the state of the works that was built or constructed at the point when the drawings were produced. If the architect accepts the as built drawing submitted by the main contractor and even relies on those drawings for the purposes of submission to statutory authority, there is a strong argument that the construction works would have been completed from the perspective of the architect. In other words, as built drawings can effectively be a form of evidence.

Conclusion

Whilst drawings are usually deemed “technical documents” that are rarely the subject of much legal scrutiny, it is evident that this cannot be any further from the truth. Based on the preceding sections of this article, a holistic examinations of all documents including drawings should be part and parcel of a comprehensive legal review exercise.

Koon Tak Hong Consulting Private Limited