June 1, 2020


Clients are the people who purchase (and often occupy) the finished building. The client’s knowledge of building construction, particularly modular construction, varies widely. Some possess superior knowledge about all aspects of building construction; they will actively participate in the entire process and may even dictate the process itself. Others have no idea what is involved to successfully turn their concept into an actual building. They must be carefully led through each step in the process. Many clients employ an architect or architectural/engineering firm to design the project.

Concerns shared by all clients include budget limitations, schedule deadlines, and the desire for maximum value from their investment. Identifying and addressing the client’s primary concerns and needs from first contact is critical to securing the contract for the project.


The design professional designs the project to the client’s specifications. Design professionals on a particular project will consist of architects, structural engineers, mechanical and electrical engineers, building manufacturer, and others as required, such as interior designers. Design professionals ensure designs remain consistent with the client’s needs, specified products and systems, and building codes. They prepare detailed plans, specifications, and preliminary cost estimates. What, when, and by whom the design professionals are engaged will depend on the project requirements and the project delivery method chosen.


The additional element brought about by building offsite is that most localities require a third party agency that regulates the design, approval and inspection of the building at the manufacturing plant and at the construction site. The building code official (also known as a building inspector) enforces the building codes, which are assemblies of standards and specifications that are designed (1) to establish safeguards in design and construction of buildings, (2) to protect people who use the buildings from fire and other hazards, and (3) to further protect the health and safety of the public.

The building inspector is the official charged with the administration of enforcement of the building regulations and has a tremendous responsibility and authority. No matter how detailed the building code may be, the building inspector must exercise personal judgment in deciding compliance with the code. In view of this fact and in view of the fact that building regulations are in the interest of public safety, public security, and public welfare, it is important to have a capable, qualified administrative official.


As the hub around which the project revolves, dealers influence the quality, content, and timeliness of project communications more than any other key player. Dealers make initial contact with end-users and serve as the client’s window to the entire building process. Dealers help clients define and assign project responsibilities. They may develop conceptual building design, including floor plans, specifications, schedules and scopes of work. Dealers present the project cost to clients in a bid or proposal utilizing quotations from manufacturers, transportation companies, contractors, and subcontractors. Their proposals may include a number of purchase or lease financing options that are unique to modular construction, affording access to expanded markets for modular buildings.

The dealer’s role in the construction process depends on the type of contract, project scope, and level of client involvement. Dealers may act as a general contractor, construction manager, project manager, subcontractor, or supplier. Each of these roles carries unique responsibilities. Many dealers solicit competitive quotations from three or more qualified manufacturers to manufacture the building modules. Some prefer to work with a specific manufacturer to develop project pricing and design. Dealers purchase the building modules from the selected manufacturer and oversee the manufacturer’s performance. Dealers typically contract for module delivery, module setup on site, and building finish. They may take responsibility for the complete project including site development and utilities, or they may perform a more limited scope of work. Dealers promote effective communication between all key players and coordinate their performance to ensure successful projects and satisfied clients.


Manufacturers are classified in two categories based upon their role in the modular building process. Most manufacturers are in the “Wholesale” category. They sell exclusively to modular dealers. The second category is “Direct”. Direct manufacturers primarily sell to clients, although some also sell to dealers as a secondary market. Direct manufacturers often subcontract with general contractors on larger building projects. In this role, their scope of work frequently includes building setup and finish.

Manufacturers prepare a written quotation from design input provided by the dealer. Quotations will include selling price, specifications, scope of work clarifications and estimated production time for the project. Comprehensive design input from the dealer is essential for the manufacturer to prepare an accurate, competitive quotation. Dealers often enlist design input from manufacturers to eliminate specification gaps and clarify design uncertainties. Each manufacturer will have a different interpretation of what is required when gaps exist in the information provided by the dealer for pricing the building.

Dealers select the manufacturer for an order based upon a number of factors including: manufacturer capabilities, compatibility with actual project requirements, price, schedule, design enhancements, and performance history on past projects. Upon receiving the dealer’s order, the manufacturer prepares shop drawings and detailed specifications. After shop drawings are approved by the dealer and regulatory authorities having jurisdiction, the manufacturer purchases materials for the building and commits the order to a firm production schedule. The manufacturer is responsible for designing the building to comply with applicable building code requirements and obtaining regulatory approval for manufacturing. The client or dealer often incorporates the manufacturer’s approved shop drawings with the documents they submit for the building permit.

Evolution of commercial modular building design incorporating increasing customization and greater use of unconventional materials elevates the importance for manufacturers and dealers to communicate effectively functioning as a capable team. Unconventional designs and materials often involve working with unfamiliar suppliers, extended lead times, greater than normal design detailing, a multi-step shop drawing approval process before the material will be manufactured, missed materials delivery commitments, assembly training for production workers, and related challenges. Manufacturers must thoroughly investigate unconventional products and their suppliers to avoid surprises that impact the project. The manufacturer’s committed ship date becomes the baseline for all project scheduling. If the manufacturer encounters a problem with unconventional materials or executing an unconventional design in manufacturing, they and the dealer must cooperatively adapt the project plan to ensure the end-user’s needs are unaffected. Communication and cooperation between manufacturer and dealer must be continually refined and enhanced to ensure successful project outcomes.


Vendors supply raw materials and services that form the backbone for the entire industry. Traditional vendors understand that predictable, timely, economical performance is fundamental for commercial modular industry success at all levels. Vendors source and develop products to meet the unique challenges inherent with modular building. They serve as the raw materials buffer enabling manufacturers to customize while utilizing the just-in-time inventory process. Many vendors offer design services for systems and products they supply.

Beyond raw materials suppliers, vendors provide many services including building design and approvals, financial services, module transportation, equipment and tools supply, and software.

INSTALLERS (Set-up Crews)

Installers erect the individual modules shipped from the manufacturer into the finished building. Moving and lifting heavy cumbersome building modules carries risk of accident and injury. Safe working practices are essential.

Although jobsite installation of the modules is the installer’s primary objective, one of their most critical roles is that of dealing face-to-face with the client. The installer often has more direct contact with the client than all other key players on the project. Their conduct and their commitment to the entire project team while working through the unpredictable weather and building site challenges is often the most critical factor in the client’s satisfaction with their modular building experience.

Installers tend to specialize in small building setup involving limited scope of work, or large building setup requiring greater expertise, more specialized equipment and expanded scope of work. Typical of all modular building key players, efficient completion of their scope of work is critical for installers. Although one person can set a single module, crew size to set multiple modules ranges from two to eight people, with four people being common. Even larger crews set multistory, multi-module buildings. In one week, a single crew may schedule setup of multiple buildings at multiple sites possibly separated by hundreds of miles. They set during the day and drive to the next location at night. Everything required to complete their scope of work, including materials, design input,and special setup requirements, must be ready at each location. Often, the installer’s first contact with the project happens when they arrive at the jobsite and see the waiting modules.


One outgrowth of the modular building process serving a broader array of clients and incorporating more complex systems is increased subcontractor involvement in projects. Systems such as fire sprinklers and alarms must be designed and installed by licensed specialists. Other subcontractors may be employed when the manufacturer or installer lacks expertise with a particular material or system. A general contractor at the jobsite coordinates and manages the various subcontractors to complete the building. The general contractor ensures that safety practices are enforced and deadlines are met. Subcontractors are used to perform work scope at the jobsite including furnishing and operating cranes to lift modules. Subcontractors often install suspended ceilings, specialized roofing, exterior finishes such as stucco or brick, finish and paint drywall, connect electrical wiring and plumbing between modules, install HVAC systems, test and balance HVAC systems, install sprinkler and alarm systems, and perform building commissioning. Subcontractors may perform their work at the jobsite after modules are set by the installer, at the factory during manufacture, or a combination of both. Manufacturers and dealers can expand their market penetration through effective use of subcontractors.


Modular construction is employed primarily to shorten project durations, increase quality, and achieve greener construction methods. Typical modular buildings are designed for ease of assembly, are not restricted in scale, and can be 95% completed offsite. Modular buildings are built to the same codes and restrictions as traditional onsite construction. The professional designer of modular buildings has to strike a balance between design intent and the production process. The architect/engineer needs to understand the act of assembly, detailing and the construction process when producing detailed design drawings and specifications. The following are some common design considerations for modular construction.

In addition to the various building codes and ADA compliance standards that must be followed during the design development phase, the professional designer will also have to consider that each completed modular unit has to be:

■          Lifted at the factory

■          Transported to the project site

■          Positioned onsite by truck , crane, rollers, or other method

■          Possibly transported through the site

■          Set in place and leveled

■          Connected to adjacent modules or pods structurally, with building utilities, and with a watertight seal.

Modular components must be delivered to the jobsite. The size and weight of the planned module may limit the designer’s ambitions and must be addressed at the design development stage. Therefore, the professional designer needs to consider overall dimensions determined by transportation restrictions and manufacturing standards:

■          Module Width – typically 15 feet

■          Module Length – typically 60 feet

■          Modular Height – typically 15 feet

■          Typical Building Height

■         4 stories for wood modular

■        5-12 stories for steel modular

■.        12-20+ stories for steel and specialized precast components

Designers often work with modular grids when considering room sizes and layouts of the floor plan. Modular grids are based on two-ft increments because most made-to-stock and assembled-to-stock materials and products are manufactured in two-ft dimensions such as two-ft increment lengths of studs, steel beams; 4 x 8 plywood sheets; tile, carpeting, flooring, etc. Room sizes are limited to the number of modules that can be stitched together. If columns in the middle of open spaces are not desirable, then the designer has to devise another method for spanning across modules, which may impact transportation load requirements. Also, the height of the shop and factory doors may dictate height dimensions, and trailer and highway requirements may restrict proportions.

The exterior building skin, the most important aesthetic feature of a building, determines the weight and sizing of the structure in addition to its performance criteria of comfort, shelter, and view. Design and construction come together as the spacing of beams, columns and walls impact the appearance of the exterior and where lifting points will be placed. Exterior skins can be multi-layered with each layer performing a specific function such as waterproofing, air flow, visibility, and heat/cooling transmission.

During the detailing part of the design phase, the architect/engineer must coordinate with the fabricator and contractors to determine the tolerances for the project. Each material component in a project has its own dimensional discrepancies when one or more other materials are joined with it. Increased tolerances cost more because a higher effort of coordination is required for zero tolerance in regards to dimensional discrepancies when the elements are assembled.

Care should be taken during the design phase to account for movement of the modular components during transit. Special provisions should be made to prevent twisting and racking. It is also important for the designer to specify how the module will be loaded and off-loaded. When a crane will be used, the engineer must integrate pick points in each module to which cables or other restraining devices can be secured in order to lift it. Answers to questions such as whether the pick points will be covered by finishes, hidden within an assembly, or part of the exterior design must be determined during design development. Protection of finished modules from weather and road debris during transportation and staging onsite must also be considered.

The decision to use a crane or other type of setting method should be made as early as possible, since it will affect the design and budget of a modular building project. Crane selection, for example, depends on the weight of the load, the height clearance needed, the number of lifts, the reach of the crane, the mobility of the crane, and the availability of the crane. In general, it is more economical to use a smaller crane with multiple lifts rather than a large crane with only one or two lifts since boom size of the crane can impact streets and alleys.

Once the module has been set into place, connections must be made with its adjacent modules with a watertight seal. Where modules meet, there is a joint whose location and appearance is determined by the design grid and the type of system being used (wood, steel, precast concrete, etc.). The joints may be sealed, bolted, glued, or lapped over each other. Mateline stitching is the process of covering up seams in the exterior and interior of the modular building. Seams can be covered over or incorporated as part of the aesthetic design. For example, in walls and ceilings, finishing in the field is done by placing a sheet of gypsum drywall over the seam and taping, mudding, and finishing with the other factory-installed drywall pieces. For ceramic tile, tile is placed over the mateline and grouting is done as a single process in the field. For exterior siding, a strip of siding (brick, wood, hardi-plank, etc.) is left off the mateline and is then in-filled in the filed after the modules have been set, aligned, and joined together.


Although modular construction may save money with delivery and staging of material, efficient labor utilization, and reduction in overall construction duration, there are other costs that must be considered in comparison with traditional onsite construction. The client must consider all cost parameters when considering modular construction:

■          Productivity cost savings from offsite fabrication because experienced workers are employed year-round in a climate-     controlled environment.

■          Onsite cost savings due to a shorter construction period (reduced cost for contractor’s site overhead), less on site work and fewer construction workers needed.

■          Offsite fabrication increases the quality of the finished product and results in cost savings in terms of no change orders and rework due to mistakes.

■          Fabricators have higher overhead due to full-time, experienced workers; sophisticated computer numerical controlled (CNC) equipment; monthly utilities.

■          Additional costs from larger capacity and dedicated transporters whereas onsite materials and products are delivered tightly packaged using shared trucks. Also, cost is based on how far the modular factory is from the project site.

■          Larger cranes may be required to set the larger modular components, but will require fewer lifts than traditional construction.

■          Larger loan draws may be required during the early stages of the project because modular manufacturers require deposits to secure the work and start the fabrication process.


Modular construction offers more reliability in meeting schedule deadlines for clients whose business income relies on opening by a certain date. The project duration is shortened due to the ability to construct the building in a factory at the same time site work is being completed. Modular construction offers several time saving techniques vs. traditional construction:

■          More than one trade can work at the same time in a factory.

■          Activities are completed in parallel: site work and foundations are being done at the same time the building is being fabricated in the factory; subcontractor trades (piping, HVAC, electrical, drywall, etc.) can work simultaneously on different modules in the factory instead of in a linear (one at a time) fashion in traditional construction.

■          Certain modules or components can be designed for easy replication (i.e., bathrooms).

■          The majority of planning, design, and fabrication decisions have to be made so early in the project that schedule savings are possible from the start of the project.

■          Weather is not a factor during the fabrication process because the labor force can work in a climate-controlled facility year-round.

■          Factories can use just-in-time delivery techniques for material procurement and staging. Often factories are working on several projects at the same time using similar material; thereby eliminating material shortage and delay problems that would normally affect the schedule.

■          Delivery and setting times are more predictably set and maintained. Experienced setting crews can set and stitch the modular components quickly.


Work scope definition describes the facilities and services that the contracting party is obligated to perform. It describes the physical work and services to be completed, the standards of acceptability, and procedural guidelines for completing the work. The definition of the scope of work is the responsibility of the client and/or the client’s representative (architect/engineer or other design professional). The scope of work serves as the basis for project plans, estimates, and schedules.


■          Describes the facility to be built (hospital, office building, sports stadium, etc.)

■          Describes the components of the facility (number of offices, classrooms, data rooms, conference rooms, etc.)

■          May describe the purpose and expectations of the project:

■          Improve performance & production capability (manufacturing facility)

■          Improve community/public services (schools, hospitals)

■.        Increase revenue for client & surrounding community (sports arena)

■         Improve visibility of community (renovation)

■.        Solve specific problems such as overcrowding, traffic congestion (highways)

■      Who or what will be served by this project (people, community, products)


■          What the contracting party will and will not provide (design, procurement, fabrication of offsite components, testing and inspections, transportation, foundations, setting and finishing, utilities, site restoration, etc.)

■          What clients intend to provide (site preparation, foundations, utilities, site restoration, etc.)


A well-written scope provides a professional method of communication, documentation to support agreement, and alignment between modular construction company (salesperson) and the client and provides a baseline for managing change.

■          What kind of information did the client supply?

■          What do you know about the facility and services?

■          What don’t you know?

■          What information do you need?

■          How do you go about getting the information you need?

■          What parameters govern this project? Schedule? Cost?

■          What is intended production life of this facility?

■          A list of services to be provided by the contractor (Divisions of responsibility should be in writing.

■          A list of included and excluded items (what the client is willing or not willing to pay for).

In answering these questions, understand the description of:

■          The facility to be built

■          Services to be supplied or not supplied

■          Who will do the work not performed by your company

Why are there inadequate scopes?

■          Client doesn’t have expertise to provide a complete concept

■          Clients do not want to spend a lot of money and time on feasibility studies, economic studies, scope definition, or other preliminary work

■          The quicker the job can be completed, the lower the overhead

■          High interest rates and market pressure (demand and competition for a product) make project duration critical

■          Good planning and scope definition is compromised to realize favorable revenue projections

Eliminating Problems with Scope Development

■          Poor scope definition ranks as one of the most frequent contributing factors to cost overruns (changes, interrupted productivity, rework, increased time)

■          Most problems stem from omissions, ambiguities, and inconsistencies

■          A poorly defined scope does not provide a clear baseline against which changes can be evaluated. Typically changes are considered either inside of outside the scope of work.



The scope of work is considered a part of the construction documents between the modular construction company and the client. If the modular building is not fabricated and constructed in accordance with the scope, time (schedule) and money (estimate) could be impacted and problems, including litigation, can result. Further, if it is found that the modular construction company was at fault because of a poorly written scope, it could result in the company being liable for damages due to delay if such a clause was contained in the contract documents.

The optimal scope of work should be the result of careful thought that balances the needs and resources of each of the parties. The scope of work must be clearly identified in all cases to avoid duplication or scope gaps. If your company has the experience, the project management capability, financial strength, and subcontractor resources, expanding your scope can give you overall better quality control of project roll out, communication, costs, and quality. The goal should be to provide a construction solution that reflects a win-win for both parties. Avoid deadly assumptions by identifying, clarifying, specifying and qualifying all aspects of the scope of work.