Every time Current Builders gets the new designs for its next big multifamily project, it puts them into a 3D Building Information Modeling (BIM) software program first to make sure what’s been envisioned on paper will actually work— instead of clash—with the real world.
“Bridging the gaps between design ideals and the realities of construction is what BIM does,” says Kar Ho, virtual design construction manager at Pompano Beach, Fla.-based Current Builders, which specializes in multifamily construction. “With BIM and clash detection, we can visualize the differences and adjust accordingly before construction even starts.”
BIM programs, such as Revit, SketchUp, and ArchiCAD, create 3D models to map each detail of a project before it’s built, essentially producing a “digital twin” of the structure that will ultimately come out of the ground. Doing so makes sure the internal systems, such as ductwork, pipes, and wiring, inside a building don’t “clash” or run into each other, and that structural components such as the foundation, walls, and floors all line up where they should.
More complex buildings
While BIM has been a staple of nonresidential projects for years, its uptake in multifamily has been slower to materialize, due to the relatively simpler, repeatable designs of apartment communities. But as the internet of things, smart-home technology, and digital amenities—all becoming essential to compete in today’s rental housing market—have made multifamily construction more complex, space behind the walls has become a premium asset.
“The key issue here is that the spaces to fit electrical, plumbing, and mechanical are not getting any larger, but more systems are being added,” says Ho. He points to entertainment rooms wired for multiple gaming consoles; municipal requirements for signal boosters at properties to facilitate emergency responder communication; co-working office spaces in common areas; and even Uber and Lyft waiting areas, along with requisite lighting outside lobbies, as new wrinkles in apartment design.
“There are more specific spaces being incorporated into today’s buildings,” Ho says. “Technology integration means instead of putting three systems in a 30-inch space, you now have to fit in six.”
A new ‘must-have’
That means using BIM in the design and construction process of apartment buildings is now critical. “Today, on any project over $30 million, BIM is becoming standard practice,” says Raffi Holzer, CEO of New York-based Avvir, which builds digital twins of buildings as they’re constructed to root out mistakes for builders and designers. “On high-value construction, it’s a must-have.”
Indeed, a 2018 study by researchers at Washington University in St. Louis found a significant increase in BIM usage by multifamily contractors compared with four years earlier.
Making the same mistake, floor by floor
Multifamily has been slow in arriving to the BIM party is partially due to the design aspects that can make these projects so lucrative. “Multifamily design tends to be relatively cookie cutter,” says Holzer. “If you get everything right on the first floor, you should be okay.”
But with today’s more complex buildings, the opposite scenario can play out if mistakes are replicated. Holzer relates the horror story of a planned, 50-story building reaching its height limit after only the 49th level was put in place, due to the contractor pouring 10-inch thick floors instead of the 8-inch floors called for in the plans. Those kinds of repeatable errors can quickly steal space—and money—from a multifamily project, the value of which is ultimately determined in the rent-per-square foot it can generate.
“The designer might allocate a 12x12 duct space in their plans, but not account for the insulation taking up another 2 inches,” says Ho. “Then, that affects where the sprinkler system placement goes. It ends up having a butterfly effect.”
Drag-and-drop product specs
Manufacturers also have gotten into the BIM game to make it easier for designers and builders to spec their products. Several companies offer free downloadable object-and-system files that can be used in major 3D BIM design software.
The ability to drop in the specifications of the actual products you’re using on site not only helps ensure that tolerances line up as planned, such as fencing near a property line, but also creates a record for operations years down the road when items need to be replaced.
“We make sure the information we get from the manufacturers is then catalogued and tabulated so it can be utilized in the future,” says Gautam Shenoy, BIM director at architectural design firm Steinberg Hart, which recently used BIM and clash detection in collaboration with Suffolk Construction on MIRO, a 630-unit, twin tower multifamily project in San Jose, Calif.
BIM beyond construction
BIM also is becoming a critical tool to create a single source of truth for the ongoing operations and maintenance of buildings down the road. “Not only are we utilizing it for construction, but many times it helps inform operations and maintenance about which systems are where in the future,” Shenoy says.
That means operators don’t have to re-measure an apartment’s square footage every time it turns over or template the exact pattern of the carpet in a hallway because the original building plans provide an accurate shopping list for the exact amount of floor covering that’s needed while eliminating ongoing waste.
“Over the first 25 years of a building's operation, owners spend $10 a square foot in waste on inefficiencies in maintenance and renovation,” says Holzer. “So in addition to the advantages during design and construction, you have an accurate, as-built model of the building at the end of construction as well.”
It’s one more way multifamily design and construction is driving full speed into the future.
