For project owners, one of the more satisfying parts of building a new facility happens during the scoping and planning phase when architectural designs are being drafted. Undoubtedly, envisioning the finished project in the landscape creates a sense of excitement.
In addition to determining which type of construction is necessary based on the use of your facility, you’ll also need to determine whether to build a single floor vs. multistory structure. The aesthetic differences may certainly play a role, but you’ll also want to consider the following criteria when working with your architect and construction manager to determine your building design.
Land Use and Development
For some, available lot size or acreage may influence whether a building is spread out on one level or needs to go vertical. From a practical sense, a single-story building clearly requires more land than a comparably sized two-story building with the same square footage. In much of the Upper Midwest, however, land is plentiful and relatively affordable. With the exception of some urban areas, the costs to purchase more land may be relatively negligible in the grand scope of things.
Other factors may influence a decision, however. An expansive facility may require additional sewer and utility work. If there are unsuitable soils, measures will need to be taken to ensure a solid foundation, such as the addition of rammed aggregate piers or over excavation. An expansive single-story floor plan will require more effort and expense to remediate unsuitable soil conditions. Other considerations for land use include adequate parking space, outdoor recreation areas, setbacks from adjacent properties, and more. All these factors will influence how much remaining land is available for the footprint of a building.
For smaller commercial buildings under 6,000 square feet, the cost differences between one floor and two aren’t terribly significant. Once a commercial structure tops the threshold of 6,000 square feet, however, other factors come into play.
Code typically requires the installation of elevators for multistory structures that exceed 3,000 square feet on floors above or below the main, grade-level floor. Such a building will also require stairwells and additional vestibules. Not only do these features add costs, they also take up as much as 10% of available square footage intended for business operations. A 6,000-square-foot design may end up with only 5,400 square feet of actual usable space in a two-story facility. The only way to recapture that capacity while still maintaining the multistory design is to add more overall square footage.
Once you go beyond two stories, the construction costs continue to rise. Cranes may need to be brought to the construction site to lift building materials to upper levels. Additional safety program measures also need to be added for fall protection, potentially slowing down workers and increasing labor costs.
For structures greater than 3,000 square feet per floor, it will likely be more cost effective to build a single-floor building. That said, you’ll eventually reach a break-even point for larger scale facilities beyond 20,000 square feet where it might be worthwhile to evaluate multiple floors.
The decision to go from one story to two stories doesn’t just revolve around construction costs; there is an environmental cost as well. For example, an expansive roof will have more water runoff that needs to be dealt with. A facility’s roof is also where the greatest amount of energy loss typically occurs.
For example, take a look at the difference in vertical surface and exposed roof surface for a simple rectangular-shaped 6,000-square-foot facility:
Single floor: 6,000 sq. ft. roof | 4,000 sq. ft. vertical surface (10,000 sq. ft. of exposure)
Two story: 3,000 sq. ft. roof | 5,500 sq. ft. vertical surface (8,500 sq. ft. of exposure)
The two-story facility has half the roof exposure and 15% less overall area that is exposed to direct environmental impact, typically making it more energy and cost efficient to heat and cool.
As a building with a square footprint exceeds 5,000 square feet, less daylight is able to penetrate deep into its interior. Sunlight penetration into a space can reduce heating costs in winter while sun can be shaded in summer to minimize cooling costs. A taller building with a smaller footprint works passively to conserve energy. It’s also important to note that natural sunlight is generally considered to have a positive psychological impact on workers. Meanwhile, there may be negative aspects of splitting a workforce between multiple floor levels.
Take a Balanced Approach
When determining your building design, it’s important to take all these factors and more into consideration. Sometimes, project owners take a combined approach to achieve a balance between aesthetics, functionality, and costs. In the end, the goal is to achieve a pleasing design that can serve the needs of an organization for years to come.
Make sure you work with a construction firm that can guide you through the pros and cons of the various options to help you make the best decision. Contact the commercial construction experts at The Samuels Group for a complimentary assessment and to talk through your needs.