September 12, 2016

Field Notes: Modular Construction for Mid-Rise Affordable Multifamily Construction

Modular schedule

By Hilary Noll, Enterprise Rose Architectural Fellow

The current Enterprise Rose Architectural Fellows share their ideas, inspirations, and photos from the field on our blog. Learn more about the Fellowship.

Drawing: Modular Schedule – Time Savings. Source: MIT 2012

The countdown is on! First Community Housing will be breaking ground on Second Street Studios, a 135 unit development serving chronically and formerly homeless just south of Downtown San Jose, California. Like other FCH developments, Second Street Studios will achieve LEED Platinum green building certification -- but the method utilized for this five-story mid-rise project is like something FCH and its partners has never done before: modular construction. There are numerous benefits of modular construction, particularly in mid- and high-rise multi-family affordable housing sector. However, there is also a greater degree of coordination and integrated project delivery (IPD) management required to achieve success. Our team recently took a tour of a modular project current under construction in the East Bay to help us learn what to anticipate during construction administration of Second Street Studios.

Modular construction is rapidly emerging as a competitive alternative for a number of reasons. The benefits potentially include higher financial return due to less construction interest carry and related time savings through shorter construction schedule and potentially reduced hard costs due to repeatable and higher efficiency construction methods, streamlined process, reduced material waste, innovation in sustainability, and higher construction quality.

Photos: Modules set on concrete platform; floor plan and module placement laid out on platform

Development and operating margins in real estate have continued to diminish as the industry has been more efficient. For affordable housing developers, this squeeze is worsened by cost containment regulations in tax credit and other financing. In response, substantial innovations have occurred in past several decades in capital markets, financing, design, marketing, operations, construction delivery and materials. However, relatively few innovations have occurred in construction sequencing and process, as each project is built predominantly in the same order: design, site work, foundation structural, exterior, mechanical and finally interior finishes. Some innovations are out there, such as Integrated Project Delivery and “fast tracking” a process by which a project breaks ground prior to design completion.  

Since type of foundations (slab-on-grade vs. deep footings vs. piers) and construction (concrete vs. steel vs. wood) can typically be decided early on, work can commence on these portions before the full project is designed. This allows final design and some construction work to occur simultaneously thus saving time and some costs related to construction loan interest carry. Even these approaches are relatively new in the development industry and not widely adopted. But these and other substantial changes in construction practices may be a final frontier in harvesting financial yields in development. To that end, modular construction appears poised to address financial, scheduling and other concerns in development and construction

The Second Street Studios floor plan showing the
modular grids, mate lines and arrangement.
We were able to align mate lines so the double-
thick party walls occur between units.
Drawing by Rob Quigley Architects and Guerdon.

Over the past two and a half years our team has worked closely with our architect, Rob Quigley, general contractor, Branagh Construction, and modular fabrication contractor, Guerdon to incorporate design changes to our construction drawings to switch from conventional stick-frame to modular. Guerdon’s business development manager shared a trend in mid-rise multifamily projects electing modular construction pretty far along into the design process, often well into DDs, or, as in our case, even at 50% CDs.  While this isn’t necessarily problematic, it would be ideal for a project team to evaluate and select modular construction earlier in the process. With modular in mind at the outset, design teams can improve and optimize outcomes leveraging greater knowledge of modular-specific parameters such as module proportions, grid alignment standards, MEP integration, optimization of modules, hybrid construction as well as design consultation from the modular fabricator.

Research has shown that modular multifamily construction, offers a chance of occupancy on a 50% faster timeline. Such streamlining allows developers to get a quicker return on investment. Duplicating building elements can add speed and precision, is quicker and more exact. Design costs drop each time a building section is replicated because major portions of the ensuing projects are the same. With each replication, the design costs are spread out over multiple projects, reducing the cost on a per-project basis.

Direct environmental impact on site can also be reduced: there are potentials for waste reduction, lower levels of pollution as well as dust and noise pollution.  However, there are a great deal of sustainability and green building metrics which have not been fully investigated in terms of modular construction.  For example, depending on the distance from the job site to the modular factory, the total carbon-footprint, embodied energy of materials, etc., will vary significantly.  I would be curious to review Life-Cycle Assessments (LCA) for various modular projects to understand these implications for future projects. Now though it’s hard hats on as we design, build and work to fully optimize and better understand this evolving construction approach.

Photos: Hilary Noll

About the Author: Hilary is hosted by First Community Housing in San Jose, Calif. Since 1986, FCH has created housing for more than 3,200 low-income residents in 16 affordable rental housing developments throughout the San Francisco Bay region. Hilary supports FCH’s efforts to develop and build affordable housing that emphasizes sustainability.  She works with FCH to raise standards and practices for design excellence, assist in building the first Living Building Challenge-certified affordable housing and create compelling graphics to illustrate building features which can be used to educate the public and the profession.

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