Tuesday, December 10, 2019

Modular Construction -vs- Three Critical Challenges

A number of interrelated challenges within the USM building program have evolved from recent exchanges with Board of Regents members and State officials, including:

1.       Higher project costs.  The overall cost of our projects is too high, due in large part to the current construction market.

2.       Poor bidding climate.  Our lessened ability to attract quality bids (and sufficient qualified bidders—particularly subcontractors in the skilled trades) may be one of the reasons why costs are so high.

3.       Reducing energy and enhancing sustainability.  This is an ongoing challenge, but one where improvements in how we build may help achieve better results.

One technology that has been mentioned in the context of reducing costs is modular construction. According to a variety of sources, modular construction could perhaps help provide a solution for all three of these challenges, at least for certain projects.  Here are a variety of reasons why this may be so.

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One publication describes modular construction as…

A process in which buildings are manufactured off-site in factories, under strict quality controls, but using the same building codes and standards as conventional construction methods. These buildings are made in modules or small parts, which are transported to the construction site and assembled…. Permanent modular construction is a sustainable building method, which uses lean manufacturing techniques to prefabricate single- or multi-story buildings in modular sections. PMC modules can be adapted to existing buildings or assembled by themselves. These modules can be completed with MEP appliances and interior finishes in less time than its site-built counterpart.

Not every building type is a candidate for a modular solution.  Common applications of modular technology include housing, medical offices, maintenance facilities, and support buildings. For a college campus, residence halls are an option, as are smaller administrative service buildings and remote research facilities. Few large projects are completely modular. Some require more traditional techniques (e.g., on ground floors or for areas with higher ceiling requirements) be matched with modular building. Regardless, the result can, according to the literature, save both time and money for the owners. Which brings me to my next point.

Benefits of Modular Construction

Multiple articles (here and here, for instance) and myriad modular contractor information sheets discuss the benefits of modular construction as an alternative project delivery method to the traditional “stick built” process.  Depending on the project and situation, these sources describe the benefits as:

Speed of build.  Modular building projects can be completed 30-50% quicker than traditional construction methods. By choosing to build modular, the indoor construction process can take place alongside site and foundations work and there’s no need to worry about weather delays.

Off-site construction.  Modular buildings are constructed off-site in modules and are then brought to your site in flat-packed panels, ready to build. Building off-site is transforming the construction process for businesses, schools and individuals, ensuring better construction quality management and less disruption.

Elimination of Weather Delays.  60-90% of the construction work is completed in a closed factory environment, and this mitigates the impact of unfavorable weather. With conventional construction methods, work must often be suspended completely on days with harsh weather conditions.

Minimal impact on your business. The beauty of building modular is that it removes 80% of the construction activity away from the actual site location – so you can keep your school or business running smoothly with minimal impact and disruption.

Eco-friendly materials.  Modular buildings are kind to the environment – they are built with eco-friendly building materials and are leading the market with the use of recycled materials. The off-site construction process ensures less waste, too. One of the benefits of modular construction is that you can be sure that you are investing in a sustainable construction process from start to finish.

Cost-effective.  Modular constructions are very cost-effective, with flexible payment options available and a shorter construction time. The design service is often included too so you don’t need to worry about architect costs on top of building expense.

Flexibility.  Many modular buildings can be disassembled and relocated for new purposes, reducing the demand for raw materials and energy usage required for construction. Even if the project used Permanent Modular Construction, recovering materials and modules is simpler than in a normal building.

Less Material Waste.  Waste is eliminated by recycling and controlling inventories. Building materials are also protected from the weather since everything is kept inside the factory. Modular construction also makes it easier for construction workers to prevent waste, since there is greater control over project conditions.

Strength.  Modular buildings are generally stronger than site-built structures because each module is designed to withstand transportation and lifting. Once together, the modules are securely joined into a whole integrated assembly.

Air Quality.  Factory controlled settings allows materials to remain dry during all stages of construction. Therefore, the level of trapped moisture in new constructions is reduced, improving air quality. This helps control mold, dust mites and other organisms that thrive with moisture.

Safety.  Working indoors allows a safer environment, it reduces risk and hazards present in construction sites. With conventional construction methods, work must often be performed at height or in uncomfortable positions where accidents are more likely.

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Like their stick-built counterparts, modular facilities can feature the following:

Attractive design.  Thanks to innovative and practical design, using the best quality sustainable building materials, modular constructions are an extremely attractive addition to your school, business or residential property.

Flexibility.  Each modular building can be tailored to your needs. Modular buildings can be custom-made to fit with your exact space and budget requirements.  Whether you need extra space for a garden room, office, studio, school classroom or music room, modular buildings can meet your requirements with the perfect flexible extra space. Many owners use modular buildings for more than one purpose and they can be designed accordingly.

High quality construction. The nature of indoor construction means that quality and safety is guaranteed and the building materials are protected from moisture and weather during the construction process.

Durable materials.  Modular buildings are constructed with the most durable building materials to ensure that your modular construction is built to last. The materials used for internal walls improve sound insulation and fire-proofing, and modular building structures are extremely airtight which ensures their energy-efficiency.  By choosing to build modular, you’ll benefit from a fast, cost-effective and efficient process with environmentally friendly materials and durability built in. Green Modular buildings are all custom-made and approached with eco-friendly, sustainable design at the core.
Disadvantages of Modular Construction

As noted above, not every project is a good fit for a modular approach. There are some disadvantages to modular construction that should be noted as well, though with the right project, modular appears to be advantageous.  For instance (sources above and here):

Size.   Modules must be transported from the factory to the construction site, and this must be planned correctly. The size and properties of each element must be considered, to determine a transportation method that will not cause damage. Given the nature of transportation by road, ceiling height is often a limiting factor.

Financing.  Where applicable (and this may be an issue with a P3 private developer approach to housing, for instance), banks will normally issue a loan for a modular building that goes through two stages. These are known as construction-to-permanent loans. In many cases, owners cannot get a traditional bank loan until construction on the building is complete. Financing the project up-front becomes a challenge in this case.

Zoning Restrictions.  In some places, local authorities may not allow building modular homes. Modular buildings are quite possibly the future of construction, but it’s only recently taken off as a preferred construction method, which means local zoning rules may have out-dated, confusing, or different rules from zone to zone. As modular buildings continually become more popular, this disadvantage of modular will become rarer.  The State of Maryland regulates modular construction, but a campus on State land would likely have the ability to select the building method it determines most beneficial.

Limited Customization.  Modular buildings can certainly be customized, but there is often an extent or limit to how much customization can go into it. A modular approach must be selected from the very beginning, with designers and construction managers on board with the decision.  Where the possibility exists that the original design may not be possible to be built modular, it would be important to know early-on whether or not to go a more traditional construction route.

Limited Service Area.  The very nature of modules means they’re going to be made in a fabrication facility, then they must be shipped to the building location, which can be extremely far away, depending on where that location is and where the nearest fabrication facility is. The costs of the transportation can be extreme, and can create difficulties with the build, making conventional construction the possible better choice.

Moisture and Mold. The emergence of modular assemblies as an option for new construction is becoming mainstream. However, this industry has had its share of mold and moisture problems, especially in warm and humid climates like the Southeast United States. Both wood-frame and steel-frame modular construction have experienced problems with condensation in crawlspaces, marriage walls, and ceiling-to-floor cavities, resulting in deterioration of the wood and wallboards, corrosion of metal floor pans, and proliferation of mold.

The greatest risk of modular construction failures has occurred when it is used for hotels, student housing, senior living, or soldier housing—generally, facilities that are domicidal or multifamily in nature. The reason for this risk probability is due to inherent similarities in requirements for the living units of these types of facilities, such as an individual cooling/heating unit, bathroom exhaust, and some sort of central HVAC makeup air system. Additionally, the abundance of modular boxes in these kinds of buildings increases the number of marriage wall interior cavities and ceiling-to-floor cavities that otherwise might not be required in other types of modular construction. Care must be taken to be sure modular facilities achieve maximum ventilation and dehumidification, while also maintaining the aforementioned thermal/energy efficiency.

"The nature of modular construction makes it difficult to repair once water or mold damage is found.  Sometimes the damage can be such that the modular building has to be deconstructed to remove deteriorated materials, and then re-designed and re-constructed using conventional methods. This essentially causes the advantages of modular construction to dissolve away as the building gets converted to a traditional 'stick' wood-frame building or a traditional steel structure building." (Source of quote) 

It’s not unique to modular facilities, of course, but it’s definitely something we want to keep in mind as we’re building student housing.  

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A modular construction company post describes the problem in a nutshell, specifically:

The national average shows a 64% shortage of workers across all trades for the amount projects that are currently being undertaken. Everyone is fighting for the same workers, and have the same needs. So, while the modular concept is one that seems to be a good and likely alternative, there is a skilled workforce epidemic going on right now in the construction industry. The modular industry and potential growth may be more than a simple trend, this may be something the industry sees as a solution to the much bigger need of worker shortages.

Why is this the case? Why would the modular industry be less impacted by a skilled labor shortage?  More importantly, how can the modular building industry assist the nation in rebuilding its industrial employment infrastructure? The Modular Building Institute offers the following explanation:

Currently, the modular industry in the United States accounts for about 3% of all new building and home construction starts, a much lower adoption rate than in other developed nations. In Japan, for example, nearly 20% of all homes are constructed with an industrialized or prefabricated process. Sweden has the highest adoption rate with a whopping 84% of detached homes prefabricated.

There is a major difference between the US (and Canadian) industry compared to other European and Asian countries. In North America, we still construct buildings piece-by-piece, nail-by-nail, site-by-site, with all the variables, conditions, and challenges associated project-by-project. Other countries approach their construction industry with a manufacturing and assembly focus. They think in terms of processes instead of projects with a goal of minimizing waste and inefficiency

Many countries are embracing industrialization in part due to difficulty in finding labor, but also due to the high demand for more affordable housing inventory. In the U.S., we currently have:

1. A shortage of skilled construction labor.
2. A shortage of decent, affordable housing inventory.
3. A vastly under-utilized manufacturing base/ infrastructure.
4. A need for more stable, predictable jobs.

The modular industry can offer more predictable work locations and hours, less labor-intensive work, a higher degree of technology integration in the work place, and much safer working conditions.

An industry publication, here, shared the following vision:

Labor to fill modular building factories “could come from ‘non-traditional’ sources that the construction industry has not or cannot tap. Imagine a new automated facility in your town, employing men, women, minorities, and the disabled. Swinging hammers would be a thing of the past, replaced with programmers monitoring the automated equipment utilization for wall assemblies.

“Imagine a whole new generation learning about 3D modeling and animation on computer screens to simulate actual projects in order to prevent costly on-site errors. Doesn’t this sound much more appealing to young people than what the construction industry is currently selling? This is not a fantasy.

“Imagine a whole new army of construction professionals focused on reducing CO2 emissions and construction debris waste while building more energy efficient buildings in a safe, indoor working environment.”

The last point is a perfect segue into the final section of this post.


Traditional building offers a variety of ways to achieve a sustainable final product—both in terms of construction and operation.  Again, for the right building type, a modular approach can achieve levels of sustainability (or “green,” if you will) equal to or, in some categories, beyond that possible with a stick-built facility.  A variety of excellent articles (including this one) point out the following advantages of modular construction through the lens of sustainability:

Waste Control. Individual modules are produced in factory settings, which allows better control over inventories. The leftover materials are recycled for future projects, reducing the construction waste that ends up in landfills. Materials are protected from moisture and weather conditions, and the risk of theft is greatly reduced.

Construction Quality. The bulk of a modular structure is completed in a controlled factory environment, using dry materials to prevent trapped moisture. This improves construction quality, while preventing issues like moisture damage and mold infestation.

Modular Buildings are Reusable.  Modular buildings can serve multiple purposes during their service life, and can be deconstructed without generating demolition waste.

Recycle and Reuse.  A key advantage of modular structures is that they can be dismantled, relocated, and reused with minimal modification. As a result, modular construction allows for double waste reductions. First, the amount of waste is minimized initially with controlled modular construction methods. Also, by reutilizing modules, the need for new materials is reduced. This also minimizes the amount of energy required for a new construction.

Increased Adaptability.  Modular construction allows for modifications or alterations in existing building, with minimal disruption for adjacent buildings or locations. In conventional buildings, renovations produce a large amount of waste that is difficult to reuse.

Reduced Site Disturbance.  Since most of the construction process takes place offsite, there is less impact on the project surroundings. Modular construction reduces the amount of vehicles and heavy equipment required on site, which translates into reduced pollution and less site disruption.

Energy Efficiency.  Modular construction also provides an opportunity to incorporate energy efficiency measures directly in modules. The following are some examples: Energy efficient windows with low-emissivity coating; LED lighting with occupancy sensors; and High-efficiency HVAC systems.

In a world with a growing concern about the environment, industries are developing methods to reduce their footprint on Earth… Modular construction plays a major role in making the building sector more sustainable.

A paper delivered recently at a University of Florida conference on Tropical Architecture included an excellent summary of the benefits and drawbacks of modular construction in general, then cited a number of key reasons modular construction may benefit vulnerable coastal (flood-prone) areas. Modular design provides not only a quicker way to rebuild following a climate event, but can also help create a more resilient community for the future. Specifically, the paper mentions the following:

·       Faster replacement of damaged buildings: The controlled factory-environment facilitates the construction and assembly of components. If the design of the project is already completed, the factory can start the construction of the components before or right after a natural disaster occurs. However, since the building industry usually responds on a project-by-project demand, possibilities of up-front investments for prefabrication projects should be debated.

·       Affordability: Prefabricated projects typically are cheaper than conventional projects. Financing is also available for manufactured housing and can be extended to modular construction.

·       Resistance and durability: Prefabricated construction has specific building codes and requirements for high-risk areas, such as hurricane-prone areas and floodplains. Building materials used for modular buildings do not differ from conventional buildings, but the method of assembly of elements in prefabrication might increase the resistance of the whole building. While building codes for manufactured homes have been updated, there should be continuous research of methods to improve those buildings. 

·       Environmental benefits: A system that combines the techniques of prefabrication with sustainable principles has the potential to be efficient and responsive. Prefabrication has the potential to reduce waste of materials and site disturbance. A substantial advantage would be the ability to disassemble and reuse components at the end of the project life. For example, modules or components could also be returned to the factory where materials could be recycled and reused for new projects.

·       Community resilience: Incentives for regional manufacturing can also encourage the establishment of community-based resiliency and provide a tool to enhance participation.

·       Innovation: Conventional construction methods create a building that must be stable enough to resist any external force. However, this method does not always work, especially when referring to natural disasters. In the face of constant changing conditions, buildings should be equipped with mechanisms that allow flexibility and reconfiguration. Recent ideas, such as movable buildings and floating architecture, allow buildings to interact with the environment and adapt to different circumstances. The same principles that also govern sustainable development and resilience.

The authors conclude that

Coastal areas are much more vulnerable to the severe consequences of climate change. Those areas are at constant risk of sea level rise, coastal surges, and natural disasters such as hurricanes and storms. It is evident that the building environment must become more resilient to extreme conditions since the population at those areas is expected to increase in the following years. In this context, prefabrication has emerged as an alternative way not only to rebuild homes affordably, efficiently, and quickly, but also as a potential construction method that could integrate sustainable and resilient principles.