Modular and panelized projects move much of the structure into a factory, which changes how engineers approach connections, transport loads, and foundations. Offsite approaches range from complete modules to flat wall and floor panels assembled on site, and each calls for different engineering decisions. The firms below provide structural engineering services for volumetric modules (fully enclosed, three-dimensional units built in a factory), wall panels, and related offsite systems.
1. Zenith Engineers Inc.
Zenith Engineers Inc. provides modular engineering for manufacturers and developers, covering permanent modular construction and relocatable, or temporary, modular units. According to its website, Zenith's modular work began with cross-laminated timber (CLT) module design for hotel chains and grew into full design development.
The firm notes that permanent and relocatable modular projects share one common design element: transportation. Its experience also includes panelized shear walls and CLT roof sections, and its website references design and project management support for a temporary winter structure for a Stockton, California homeless shelter.
Key services: Permanent modular structural design; temporary modular design management; panelized construction design; structural analysis of modules; foundation design.
Project types: Homeless shelters, school and education additions, construction site trailers, and public works remote site additions.
2. DCI Engineers
Seattle-based DCI Engineers has a dedicated modular market group focused on factory-built volumetric construction. Its work covers the plant and the site, including the dual permitting that comes up when each falls under a different building department.
Key services: Structural design of volumetric modules; building component lists that define factory and site scopes; building information modeling (BIM) coordination with architectural, MEP, and fire protection trades; site staging engineering; construction sequencing and crane logistics; dual permitting and code compliance support.
Project types: Residential, hospitality, and workforce housing, including steel and wood modules and modules over concrete podiums (concrete base levels that support the modular floors above).
3. Thornton Tomasetti
Thornton Tomasetti's modular design and construction group works across volumetric and component-based systems. The group also builds physical prototypes and handles transportation engineering, following a module from the shop floor to the site.
Key services: Modular system design; structural analysis and design; steel connection design; fabrication and physical prototyping; erection and transportation engineering; foundation, slab, podium, and shear wall design.
Project types: Hotels, including citizenM in Washington, D.C., plus sports, office, mixed-use, and residential projects using light steel, shipping containers, concrete, light-frame timber, and CLT.
4. Entuitive
Headquartered in Toronto, Entuitive lists volumetric modular construction as the main focus of its offsite and modular practice, with project work in the United States and Canada. The team designs the modules, develops the components that get built offsite, and plans how it all goes together once it reaches the site.
Key services: Volumetric modular structural design; component development for offsite manufacture; construction strategy; on-site assembly planning.
Project types: Residential, including Cheatham Street Flats in San Marcos, Texas, and academic buildings, including work for the University of Toronto's Daniels Faculty.
5. Larson Design Group
Based in Williamsport, Pennsylvania, Larson Design Group provides structural and foundation engineering as part of a multidisciplinary modular design package that also includes architecture, MEP, fire protection, and civil engineering.
Key services: Structural design for permanent modular, relocatable, volumetric, and panelized construction; foundation engineering; coordinated multidiscipline design.
Project types: Offices, healthcare, education and dormitories, industrial facilities, data centers, laboratories, and security facilities.
6. PSE Consulting Engineers, Inc.
Headquartered in Klamath Falls, Oregon, with offices in Medford, Oregon, and Jacksonville, Florida, PSE Consulting Engineers, Inc. states that it is licensed in all 50 states. The project list runs from single-family homes up to healthcare and education buildings, and the transportation analysis looks at what a module goes through on the road.
Key services: Structural calculations and stamped permit plans; module connection details; transportation load analysis; foundation engineering.
Project types: Single-family and multifamily modular homes, accessory dwelling units, hotels, apartments, offices, retail, education, healthcare, and industrial buildings.
7. raSmith
Brookfield, Wisconsin-based raSmith provides cold-formed steel engineering that includes prefabricated wall panel systems. The work here is panelized rather than volumetric, which means wall assemblies built flat in a shop rather than finished rooms.
Key services: Prefabricated and pre-finished wall panel design; multistory load-bearing framing; curtain wall framing (framing for non-structural exterior wall systems); shop drawings; delegated cold-formed steel engineering.
Project types: Residential, senior living, hospitality, education, healthcare, retail, mixed-use, industrial, and sports facilities.
8. Salas O'Brien
Salas O'Brien is a multidisciplinary engineering firm whose structural group lists cold-formed steel design for prefabrication and modular structures. Most of the prefabrication here happens at component level: pods, headwalls, and racks that arrive finished and drop into a building framed the usual way.
Key services: Cold-formed steel wall panel design; prefabricated bathroom and office pods, patient room headwalls, corridor racks, and skids (prefabricated frames that carry equipment or piping); modular structures with detailed fabrication models and drawings.
Project types: Healthcare, education, commercial, hospitality, government and military, multifamily, and venues.
Choosing a Modular Engineering Partner
When comparing firms for offsite construction, developers and manufacturers can look at experience with the specific system (volumetric, panelized, or hybrid), coordination with factory production, transportation and lifting analysis, and familiarity with state and local approval pathways. Early involvement gives the engineer time to align module dimensions, connection details, and foundation design before production begins.
Before signing, it’s worth knowing who on the engineering team speaks to the plant, which drawings and calculations go to each approving authority, and who answers the call when a module arrives and something doesn’t line up. Approval paths differ by state and building type, so have a licensed engineer confirm what applies to the specific project.