The Triple-Bottom-Line Impacts of Choosing Modular, Part 3: Building Quality

Geared to the needs of nonprofit owners and developers of affordable multifamily housing, this is the third in a series of posts addressing the financial, social, and environmental impacts of making the shift from onsite to off-site construction.

How does the quality of modular buildings compare to that of conventionally built structures?

If we’re talking about multifamily housing, the quality of modular buildings is generally superior to that of conventional buildings. (While certain segments of the single-family manufactured home market operate under conditions that tend to drive quality downward, these conditions don’t apply to multifamily housing and commercial structures built in plants.) Three primary factors contribute to modular construction’s quality advantage:

1. Indoor construction reduces risks of weather-related defects. On outdoor job sites, harsh weather conditions and moisture can cause materials to mold, swell, warp, and tear. When these defects go uncorrected, owners can face long-term building problems and repair costs. Modular buildings are far less susceptible to weather-related defects than conventional buildings, because the modular construction process happens indoors, except for a short period of onsite assembly.

2. Modular design constraints reduce risks of manufacturing errors. In theory, modular plants can produce pretty much anything. But in practice, they usually produce stackable boxes, modules that can be transported on flatbeds and assembled with similar modules at different locations. When workers build the same box repeatedly and to high-precision requirements, their chances of making errors and bad judgments are lower, at least marginally, than when they build more complex and variable structures.

3. Transport requirements necessitate sturdier construction. Even if a conventional building is free of defective materials and construction errors, its quality will still lag that of a comparable modular building in one dimension: sturdiness. Modular structures are built extra-solidly to withstand being handled by cranes and trucked down highways. Their heavy-duty structures make them more durable, give them improved sound insulation, and can, in some instances, add thermal insulating capacity.

In sum, the quality advantages of modular construction are significant. Modular buildings are less prone to defects and more stoutly built than their site-built counterparts. These quality advantages improve resident comfort and reduce owners’ long-term operating costs.

Up next: How green is modular construction, when it comes to multifamily housing?