Modular Building Institute

MBI and BD+C Modular Advantage | Spring 2011

Combining Offsite and Site Construction



Due to the process used, the speed, efficiency, and inherently green qualities of permanent modular construction are hard to beat. Despite that, it still remains only 1% of the overall commercial construction market. Site construction contractors often have the name recognition preferred and many architects, developers, owners and contractors have yet to embrace modular construction. With the recent recession, however, clients’ are having to cut costs at the same time that energy and green building requirements are going up, creating a greater need for alternative construction methods to be implemented.

Because modular construction is built offsite in a factory, it capitalizes on the ability to move product in controlled manufacturing conditions, and on tight inventory control and project schedules. It is inherently waste conscious and can have minimum site impact if delivered carefully and strategically with respect to site constraints.

Learning Objectives

To earn one AIA/CES learning unit, read this article and the test questions, then submit your answers by clicking the Submit Test Answers link at the bottom of this page.

1. Learn about the benefits of  
    using permanent modular 

2. Learn examples of when it’s 
    best to integrate permanent 
    modular construction with 
    site construction.
3. Understand which parts of a 
    project the two types of 
    construction are best used 


4. Learn the keys to making
    the integration the most
    efficient and environmentally
Examples in which offsite construction can be incorporated into site construction include projects with tight deadlines, those built in secure environments, those where weather may impede construction, and those needing repetitive interior structures.

When combining the two types of construction, the permanent modular portion consists of repeatable modules that are similar in design and layout. This is an effective method of construction to use for dormitories, barracks, hotel rooms, classrooms and offices, for example, because the rooms are very repeatable and they can be built in a factory one after the other with a lot of quality control. Site construction on the other hand allows for large open areas such as lobbies, gathering areas and common spaces. Within the site built areas are elevators, mechanical rooms, electrical rooms, communication rooms, and stairways. These are spaces that are singular to the building and do not lend themselves as well to modular construction. By using the most suitable construction type for each application, builders can increase the economy of each type.

In addition, by incorporating the permanent modular construction, the construction of the modules can take place at the same time the foundation and civil work is taking place.  The cost advantage comes from a building being completed much faster and in a quality controlled environment.  Shortening the schedule and creating a higher quality product is what saves money on a project.

A key to combining the two types of construction successfully is to consider permanent modular construction during the design phase of a project.  The earlier in the process modular construction is specified, the greater the time and cost savings and environmental benefits. A team approach and early communication of the whole design and construction team greatly improve the entire process. It also helps to have people on the design-build team who are experts with both types of construction.

In large-scale, multi-story construction projects, it can be beneficial to incorporate both onsite and permanent modular construction because each are particularly suited for different aspects of a project. Combining the two types of construction, modular and site construction contractors can each concentrate on what they do best, with a little coordination. Rather than each type of builder taking on a whole project, they can divide and conquer, splitting the project into smaller, easier portions to control. In addition, both types of construction can take place simultaneously, saving time and money on a project. The controlled factory environment used for modular construction also provides a more efficient, sustainable building solution, creating a healthier and safer environment.

Following is a project where modular was successfully combined with site construction.

Fort Bliss Combat Aviation Brigade
Fort Bliss, TX

The two-story, 99,050 square foot project (86,000 sq. ft. of which is modular) utilizes the best of onsite and offsite construction by combining the speed and efficiency of prefabricated buildings with the quality and appearance of site applied interior and exterior finishes. This was achieved by employing simultaneous construction tracts.

At the same time a conventional concrete slab foundation was prepped and poured on the building site, the fabrication of the modular buildings was taking place in the manufacturing plant. When complete, the building sections were shipped to the project location, crane-set on the concrete foundation, then quickly weathered-in and finished-out on site. This form of design-build construction results in a superior facility with lower design and construction costs, a faster project completion schedule, and superior quality over older site construction methods.

“The Accelerated Building System combines the best of what factory built modular construction and site construction have to offer,” said Mike Slataper, president and CEO of Ramtech Building Systems. “It can provide a client with a 10 to 25% reduction in design costs while cutting 25 to 40% off the construction schedule.”

Because the Combat Aviation Brigade building houses U.S. combat troops, the project also meets the Army’s rigid anti-terrorism construction standards. In addition to a six inch, 4,000 psi concrete slab foundation whose footprint is larger than a football field, the building also includes blast resistant windows and doors and a building envelope encapsulation in the event of a chemical or biological attack. To meet the redundancies required for power and HVAC, a Kohler 50 KVA standby generator and 50 KVA Eaton Powerware UPS Station were installed, along with over 22 tons of redundant HVAC for the SCIF, BOC & NOC. The data and communications system features a 900 pair copper and fiber optics entrance with over 40 miles of wiring throughout the building.

To comply with the latest federal executive orders, the building meets the requirements of LEED Silver Certification and is designed to conserve energy by reducing the power consumption requirements established in ASHRAE 90.1 by at least 30%. To accomplish this in a desert environment, Ramtech utilized four sixty-ton Trane Intelipak evaporative assisted D-X self-contained roof top units. These four primary RTUs feed over 140 individual VAV boxes providing flexibility in temperatures setting throughout the structure. The entire system is connected to a base-wide Energy Management Control System through an open implementation of the LON operating system. Other aspects of LEED compliance in the building include automated lighting controls, two-stage low consumption flush valves, waterless urinals, energy star roofing material, recycling of waste materials (to achieve a 50% diversion of waste normally sent to land-fills) and utilization of construction materials with a 20% recycled content.

Fort Bliss photos courtesy Ramtech Building Systems

For more information about the advantages of incorporating modular into site-built construction, view a podcast from MBI’s latest Military & Government Construction Conference here.

(Top left) photo courtesy Britco Structures (top right) photo courtesy Ramtech Building Systems. 


AIA Continuing Education Test

1. Permanent modular construction can offer building 
    advantages in terms of speed, efficiency, and sustainability 
     due to:

A. The building type and style 
B. Its factory controlled process
C. Its site construction method
D. All of the Above
E. None of the Above

2. Examples in which offsite construction can be incorporated 
     into site construction include:

A. Projects with tight deadlines
B. Those built in secure environments
C. Those where weather may impede construction
D. Those needing repetitive interior structures
E. All of the Above
F. None of the Above

3. Permanent modular construction is an effective method of 
     construction for:

A. Dormitories
B. Classrooms
C. Hotel Rooms
D. Offices
E. All of the Above
F. None of the Above

4. Site construction is an effective method of construction 

A. Lobbies
B. Gathering areas
C. Common spaces
E. All of the Above
F. None of the Above

5. By incorporating the modular construction, the construction 
    of the modules can take place at the same time the 
     foundation and civil work is taking place.

A. True
B. False

6. Using modular construction can shortening the schedule and 
     creating a higher quality, cost efficient product.

A. True
B. False

7. Keys to incorporating the two types of construction 
     successfully are:

A. Specifying permanent modular construction early on in the 
    design phase   
B. Using contractors who are familiar with both types of construction 
C. Both of the Above
D. None of the Above

8. The two types of construction are most effectively combined 
     when building small-scale, temporary buildings.

A. True
B. False

9. One of the reasons why integrating modular into a site 
    construction project saves time and money is because both 
     types of construction can take place simultaneously.

A. True
B. False

10. In the case study, which of the following was an aspect of 
       LEED compliance in the Fort Bliss Combat Aviation Brigade 

A. PV solar panels on the roof
B. Energy efficient paint
C. Utilization of construction materials with a 20% recycled content

In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery at and clicking on the course evaluation link on the left side of the page.




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