Discussions of commercial flooring tend to focus on the floor covering or finish material. This is hardly surprising, since the covering is the part of the floor that stakeholders see, interact with, and care about most. The lion’s share of information from commercial flooring contractors and product manufacturers focuses on surface material, revealing little about what’s going on below the surface. For every rare discussion of structure, subfloor, and underlayment, there are dozens about what should be chosen to place on top of the flooring base.
The uninitiated might conclude that the only important choice to make is the specification of the flooring material and the means to adhere it.
Savvy Building Teams are careful not to fall into this trap. The finish material for a commercial or institutional floor system interacts in important ways with a number of other building systems. For that reason, the effective selection and specification of materials, adhesives, underlayments, leveling treatments, electrical systems, cable management, and raised floors must take into account a complete picture of both building design and intended use.
Beyond that, architects and structural engineers must consider how the interiors team will craft the space to meet end-user needs before making all the decisions concerning subfloor materials and structure. Even operations and maintenance (O&M) considerations, such as cleaning and future renovations, are vital to the design of assemblies and choices of products.
After reading this article, you should be able to:
+ DISCUSS the main criteria, notably environmental, health, and safety issues, for selecting and specifying floor materials and systems.
+ DESCRIBE the structural factors for flooring and floor underlayments, including raised-floor systems for improved indoor air quality (IAQ).
+ LIST considerations for entry areas, building transitions, and other special areas that require flooring accessories, with particular attention to safety, occupant welfare, cleanliness, and benefit to the indoor environment.
+ COMPARE and contrast flooring materials and finishes based on cost, sustainability, health and safety concerns, and O&M requirements.
A floor designed from too narrow a perspective can be underperforming, even disastrous, as field experience proves.
SUPPORTING HIGH-PERFORMANCE FLOORS
Experienced Building Teams know that design success and client satisfaction may hinge upon a “top-down” view of the floor systems, starting with a careful assessment of the needs implied for a properly specified and installed finish surface.
“Flooring is often the interior finish that represents the largest surface area in a project,” says Layng Pew, AIA, managing principal with the planning and design firm WXY Architecture + Urban Design (www.wxystudio.com), New York, N.Y. “It is also the finish that every occupant will touch—that is, walk on—daily, and there are many considerations that factor into the choice.” These include:
- Client needs, requirements, and desired aesthetic
- Subfloor composition and structure
- How occupants will use spaces
- O&M practices and preferences
At least three of those design and construction topics relate directly to the needs and wants of the client, says Pew, a 25-year veteran of building design and project management. “It is essential to include the client in the decision-making process, because each has unique needs and expectations,” he says. Communication in the planning phase reveals important information about how the space will be utilized—information that is crucial to choosing a floor design. Continuing the dialogue through construction and into operation phases will prepare the client to make the best use of the floor.
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Assessment of space usage will determine the requirements not only for flooring materials but also for the load-bearing structure beneath. The information can be used to manage client expectations with respect to project cost, materials performance, and choice of finish materials. “The key is to make sure you truly understand how the floor will be used,” says Caroline Robbie, a principal with Quadrangle Architects Ltd. (www.quadrangle.ca), Toronto.
Building codes may help determine minimum load-bearing requirements, but the realities of the space, the likely occupants, and the planned usage in specific areas are all predictive of the amount of wear the floor will have to endure, and what kind of maintenance program would be optimal.
As an example, hospital floors suffer from static load and movement of hospital bed and gurney wheels. While resilient flooring is more conducive to rolling patients down corridors, it works best with flat-wheeled equipment, which prevents damage to vinyl, linoleum, and the like. For carpeted areas, narrow wheels work best. In patient rooms and other areas where hospital beds are used, strong adhesives such as epoxy-based products may be recommended by flooring manufacturers to protect the finished surface.
STRUCTURAL FACTORS FOR FLOORS: LOAD CAPACITY, MATERIAL COMPOSITION
Structural considerations for commercial floors fall mainly into two categories: load capacity and material composition. Load capacity has a number of ramifications for the design of interiors generally and especially for the floor. Building codes will help determine what options are available—and the limits to those possibilities.
“The building codes require substantially more structural capacity for assembly uses than residential or office uses,” notes James Rappoport, AIA, NCARB, vice president of Philadelphia’s Daroff Design (www.daroffdesign.com). “Our first review is to determine the use and occupancy of the space and then to confirm the structural capacity of the floor.” According to the American Society of Civil Engineers Structural Engineering Institute, a minimum live-load capacity of 100 lb/sf is recommended for “public assembly occupancies,” such as large meeting spaces, dining areas, and the like. This compares to minimum load capacity of 60 lb/sf for office usage and 40 lb/sf for residential uses.
These minimum capacities may determine the feasibility of a renovation project. “While it’s technically possible to reinforce a floor from a residential or office structural capacity to the assembly capacity, the cost for this reinforcement is very high,” says Rappoport. “We see many assembly projects come to a halt once the client realizes just how expensive it is [going to be].”
The second category—materials composition—further complicates the matter. Let’s look at these factors one by one.
Concrete: Dealing with moisture and leveling. A majority of commercial buildings have concrete subfloors, and many architects favor poured concrete. But that is so in spite of the technical challenges raised by using concrete, notes Gretchen Lotz, RID, IIDA, an architect with IA Interior Architects, Inc. (www.interiorarchitects.com). “Structural concrete slab substructures are ideal to receive most types of flooring installations,” she says. “But slabs provide myriad conditions—moisture content, levelness, cracking, slab-on-and grade conditions—that affect the installation and performance of flooring.”
Jean Hansen, FIIDA, CID, AAHID, EDAC, LEED AP BD+C, sustainable interiors manager at HDR Architecture (www.hdrinc.com), San Francisco, who works mainly on healthcare and research lab projects, says, “We’re accustomed to working with concrete as the substructure, but we have to make sure that we have the absolute best concrete surface available to put that flooring product on.”
“The main issue is settling, whether it’s an existing floor that has already settled and may be cracked, or a new floor that’s likely to settle and crack over time,” says Mike Krochmaluk, LEED AP, a designer of corporate interiors with STUDIOS Architecture (www.studios.com), New York, N.Y. “Cracks and other imperfections in the concrete will ‘telegraph’ through the floor at the grout joints or by cracking the flooring itself, in the case of stone and terrazzo.” Krochmaluk suggests that an anti-fracture membrane applied as underlayment may solve this problem, by reducing the effects of settling, structural movement, and uneven surfaces. Some membranes also serve as a waterproofing product.
According to the experts, concrete problems almost always are related to settling or moisture. “We are super-sensitive about the moisture content in concrete floors, and we will often take a core sample to test the moisture level, if possible,” says Todd Baisch, AIA, RID, LEED AP, a principal in Gensler’s Chicago office (www.gensler.com). Newly installed structural floors are generally too moist to receive floor coverings. Wood installed over new concrete may warp or buckle; adhesives may fail. Carpeting and carpet tiles present a number of potential moisture-related worries, including mold, odor, and deterioration of the material. Manufacturers generally recommend the Carpet & Rug Institute’s installation standard CRI 104, to test for pH levels and moisture before installation.
Building Teams employ a variety of solutions to the concrete moisture issue to help speed projects and ensure a lasting floor assembly. New, rapid-drying concrete mixes are available that have desiccant properties. For wood flooring over concrete, some teams employ a closed-cell foam underlayment between a floating wood floor and the concrete slab, for resiliency as well as moisture control. Consulting the manufacturer’s product information can help find solutions like these.
Concrete may also present concerns related to uniformity and levelness, possibly creating conditions that may even be in violation of codes related to the Americans with Disabilities Act (ADA).
If the floor is not poured to the specifications of the Concrete Institute’s finish and level guidelines, the interiors team may arrive on the job already over budget and behind schedule. “The cost to prepare a poorly installed concrete floor slab could be $3.00/sf or more,” warns Daroff Design’s Rappoport. Leveling compounds may solve the problem, he says, though at an added cost: “Because adding a self-leveling topcoat adds moisture, remediation work can delay the project by weeks.” Still, leveling compounds can be a valuable technology, especially in renovations where the concrete slab has already settled.
Of all the worries about concrete, “concrete moisture continues to be enemy number one in all flooring failures in schools and hospitals as well as commercial offices throughout North America,” says Ray Darrah, a flooring inspector with Cali-Floor Technical Services, Sacramento. When the cool concrete meets warm air, moisture condenses on the exposed surface wherever the concrete is exposed to air for any length of time. “Concrete does not require extended lengths of time to accumulate enough moisture from the air to cause the new flooring materials to fail,” Darrah adds.
Wood subflooring and underlayments. Though concrete dominates the commercial subfloor segment, Building Teams must be prepared to cope with alternatives. “Structural systems encountered vary with each project,” says Quadrangle’s Robbie. “For example, a renovation may have an original heavy timber floor with wide variations in level.”
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Wood substructures like these create unique problems for flooring replacement, especially if adhesives were used. But as adaptive reuse projects have become more common around the country, a growing range of technical solutions have also become available. “New, thin anti-fracture membranes allow almost any material to be used over old, uneven, or wood-framed substructure, as long as the structural capacity is there,” says Andrew Franz, AIA, LEED AP, principal of Andrew Franz Architect PLLC, a New York-based firm.
Veteran designers note positive experiences with the anti-fracture membranes, yet they also recommend that such underlayments generally remain low on the list of the Building Team’s go-to solutions. Adding layers complicates an already complicated engineering dilemma, they note, and the flooring material must be compatible with any chosen product. “Manufacturer warranties for flooring material must be considered when installing the underlayment,” adds Lotz.
For most projects, Building Teams are unlikely to specify an underlayment except for reasons of improving acoustics between floors. According to Frank Kroupa, technical training director for the National Wood Flooring Association (www.woodfloors.org), Chesterfield, Mo., in multifamily residential and hospitality applications, “almost all floors in high-rises are poured floors, and almost all of them want to dampen sound transmission between floors.” A layer of cork or synthetic acoustic material will usually serve the purpose. Krochmaluk says he uses felt between wood and concrete in his corporate projects. For offices and other applications where sound transmission between floors is not as crucial, the Building Team and client might prefer carpet or carpet tile as a sound-dampening floor finish.
Some adhesives for wood or other flooring contain a soundproofing component, a newer technology that may eliminate or reduce the need for an acoustical layer. Underlayments must also be carefully specified for particular conditions, says Franz, who notes that acoustic underlayments are a routine item for urban residential construction. “We specify water-resistant fiberglass products beneath wet areas, and recycled rubber or fiber membranes beneath other dryer assemblies,” says Franz. He warns, however, that floor failures can result from applying the wrong type of layer.
In spite of the caveats, underlayments do have their place, says Interior Architects’ Lotz, noting they are of great value when properly specified for acoustics, leveling, and aesthetics. “Two of the most durable, high-performing, and sustainable options are gypsum underlayments and self-leveling cementitious products, which can be applied to most types of existing subfloors or concrete structures,” she says. These underlayment types can make the difference in a project with an uneven subfloor.
Adhesives: Multiple concerns. Glues and adhesives must be carefully specified with respect to: 1) interaction with the product backing and subfloor materials, 2) the likely maintenance and operations program, and 3) green design principles, since many formulas contain volatile organic compounds (VOCs) and other powerful chemicals.
With respect to interaction, Mark Quattrocchi, AIA, principal with Quattrocchi Kwok Architects, Santa Rosa, Calif. (www.qka.com), notes that some applications may require high-performing adhesives to combat moisture content and alkalinity in some concrete slabs. As for green design and indoor air quality (IAQ), Quattrocchi adds, “Low-VOC-emission adhesives are critical for sustainable flooring.” Although low-VOCs are nearly an industry norm now, you should still review product literature and specifications carefully for verification.
Carpet tiles present unique problems with regard to adhesives. Some are manufactured with self-adhesive “double-stick” backing, which many designers like Baisch caution against. “Corners may start to come up, so the carpet will not appear solid,” he says. On the plus side, carpet tiles can now sometimes be installed with adhesive “dots” instead of glue, a sustainable option that works well with access floors.
Wood can be installed as a floating floor, but otherwise it requires an adhesive. Building Teams are advised to choose a glue that is strong but not too strong.
When the time comes to replace a floor, it is important to successfully and cleanly remove the covering, says Kroupa: “Otherwise it may be cheaper to put down the new wood directly over the old floor.” He recommends polymer-based adhesives where applicable, as opposed to urethane-based compounds, for two reasons: 1) polymer glues have greatly reduced isocyanate content (a VOC) and 2) they do not interact negatively with urethane-finished wood product. Urethane adhesive will cling to the urethane finish, creating unsightly spots that are nearly impossible to remove.
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RAISED FLOORS AND ACCESS FLOORS
Regardless of underlayment or finish, in some cases raised floors offer advantages for the occupants. A novel types of system known as low-profile access floors has gained attention recently for accommodating quick changes of electrical systems and data cabling. In other circumstances, the classic “post-and-plank” raised floors—sometimes called pedestal or simply grid systems—can be used for the same reasons. These systems come in two-foot-square panels, with a higher profile that allows for HVAC air delivery through flexible ducts or an underfloor plenum.
Designed properly, raised floors should not sound hollow or reverberant when walked on, and should not have any unwanted movement. “For a large law firm’s new, 45,000-sf building designed for their use, the client had already determined they would use raised-floor construction, mainly to allow all telecommunications and data cabling to be routed below the floor,” says WXY’s Pew, who specified concrete-filled, 2x2-foot tiles that were then overlaid with carpet tile. “It was almost impossible to tell that you were walking on a raised floor,” he says.
Whether low-profile or standard heights of 12-18 inches or more, raised floors are basically elevated structural platform systems sitting directly on the slab or other substructure, typically on some sort of damping padding. Created for data centers and computer rooms to route mechanical services and cables, wiring, and electrical supply, the taller versions were originally invented to cool the undersides of mainframe and midrange computing systems.
Today there are new concerns centered around information technology, says Franz. “The building IT infrastructure creates challenges for where wires can be run and how to cool the ever-increasing heat load of more equipment,” he says. “Raised floors have become a great way to have easily accessible wiring raceways that also allow for modular flexibility. They also allow ductwork to be run in a more concealed manner or for mechanical systems to focus on managing temperatures closer to areas of human occupancy, not 10 or12 feet or more in the air.”
Another reason to use raised floors is that they can ease wire management and restacking of office layouts, which is ideal for high-churn workplace environments. The low-profile type systems are not used for underfloor air, and only allow 2-3 inches of height for cable runs. A new CSI MasterFormat specification section (09.69.33) was recently added to cover the product, as it is unlike other raised-floor and underlayment products. The steel interlocking sections are typically installed by a flooring contractor and can be easily rearranged by facility staff, usually without the use of tools.
Some Building Teams prefer using raised floors because of their benefits in the occupancy phase, but others see life cycle arguments against them. “While we have some raised-floor projects in our portfolio, we still believe that a blended deck, steel underfloor duct, or other wire-distribution systems within the structural floor slab are preferred for first cost and life cycle cost when compared to an access floor installed above structural concrete,” says Daroff Design’s Rappoport.
But Quadrangle Architects’ Robbie points to another benefit of raised floors: clearing the view corridors on the floor plate of electrical feeds from the ceiling and duct chases on core or exterior walls. “The systems are always modular in nature, so flooring choices are either integrated into the system or must be modular, such as laminate tile in clean rooms or carpet tile in open office areas,” she says.
ENTRY SYSTEMS AND RECESSED FLOORING
Building Teams can also provide for raised or recessed features that protect the appearance of flooring systems in special-use areas or high-traffic zones. Entrance areas, lobbies, and vestibules have to deal with foot traffic carrying moisture and particulates from the outdoors. When entry-area flooring transitions are well designed, they can absorb or remove significant amounts of dirt and moisture from visitor and occupant foot traffic as they enter, reducing O&M demands for the building.
Clean mats are a common solution, though some Building Teams consider them the least aesthetically pleasing. They cost practically nothing to install; when they need maintenance, they can easily be removed and replaced with other mats, to be cleaned elsewhere. Moreover, they can be used with practically any floor type: hardwood, resilient, carpet, even stone. Many owners and facilities managers prefer them for their ease of operation and low cost.
“Some clients prefer to have a maintenance program in place using clean mats,” particularly in healthcare and research laboratory facilities, where cleanliness is extremely important, says HDR Architecture’s Hansen, “There are some great carpet tile alternatives. The entire vestibule can be finished with tiles specifically designed to work as walk-off mats, and the tiles can be replaced easily when necessary.”
Hansen, like many designers, prefers to specify recessed grille systems. Recessed systems, normally used in vestibules but occasionally installed in lobby areas, are long-term solutions that reduce the frequency of required maintenance. Many designers feel they do a better job of keeping the building interior clean while being more aesthetically pleasing.
The system works by covering a floor area that has been installed recessed, usually between a half-inch and one inch below grade or below the finished floor, with a walk-off covering: grilles and grille mats are two common types. Both coverings use the grille texture to remove particulates from shoes as traffic passes over, but grille mats boost the moisture absorption of a clean mat as well. Cocoa mats, rugged fibrous mats made from coconut husk and typically backed with vinyl, represent a lower-cost alternative with a long track record. Many proponents find them versatile and cost-effective, says WXY’s Pew: “They are the most straightforward and economical choice when you need a custom size or shape.” Adds Gensler’s Baisch, “We still use cocoa mats. They’re durable, not super-expensive, and only need to be replaced every three years or so.” He notes, however, that “there are better walk-off mats now.”
Today’s improved walk-off mats use special materials and often combine grille, mat, and recessed sections to protect the floor. Maintenance practices typically require the removal of the covering so that the recess well can be cleaned; some recesses may include plumbing for drainage, allowing the well to be cleaned with a hose. Recessed flooring specification may result in receiving LEED-CI credits under IEQ 5, for pollutant control, if the vestibule dimensions meet the criteria. Quadrangle Architects’ Robbie, based in Toronto, says, “We use a standard minimum depth of three meters for vestibules, which is in line with accessibility guidelines and good practices.” In the United States, 10 feet is the required depth for the LEED credit. This treatment also satisfies most ADA requirements.
“Recessed systems are preferred over mat systems because of the raised profile and potential tripping hazard with mats,” Robbie explains. Even the best recessed grills and mats may lack a clean, pleasing aesthetic an owner is looking for, so Robbie’s team at Quadrangle Architects has been recommending a novel modular recessed-flooring system combining stainless steel grilles and custom cell mats that exhibit good durability and wear resistance. The products install flush with the surrounding floor finish and, in some cases, mimic the adjacent floor finishes.
Of course, it may be ineffective to install a recessed flooring system in an existing slab due to cost or other constraints. In these cases, says Interior Architects’ Lotz, “Low-maintenance flooring installations for lobbies can be designed successfully with thin-set tile or pavers, composite flooring, or high-impact applied vinyls, without cutting into the existing structure at a premium cost.”
Rappoport offers another possible way to create a low-maintenance lobby without a recessed system—raising the floor: “You can start with the zero elevation and build up from there, but you need to add drainage to avoid mold and mildew below the finished floor surface.”
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FINISHES AND FLOOR COVERINGS
A thorough review of floor covering and finish choices is important for all areas of new or renovated buildings. In fact, there is a vast array of choices available to commercial stakeholders. But first, Building Teams should briefly survey key trends and recommendations affecting the flooring choice, as well as important information on interaction of coverings with accessories, adhesives, and adjacent building systems.
Wood flooring. A trade survey last year of hardwood flooring retailers and installers indicated that competitive pricing presents the greatest barrier to specification of wood flooring for all project types. Yet many commercial clients prefer the wood aesthetic, forcing design teams to ponder how to deliver a cost-effective, low-maintenance wood floor.
Prefinished and pre-engineered wood products offer potential solutions to this dilemma. Prefinished systems, with ultraviolet- or UV-cured urethane sealants, often contain added aluminum oxide or ceramics to increase durability. “The pre-finishes are even outperforming many site finishes,” says the NWFA’s Kroupa. For those who prefer to finish on site, technology is now available to UV-cure a finish once it has been put down. As for engineered products, which generally offer better stability than natural woods—especially with regard to expansion and contraction—the commercial flooring sector is seeing increased specification rates. Kroupa indicates that more than 50% of the market for wood flooring is for over-concrete applications; engineered wood flooring is specifically designed for installation over concrete.
But even as the technology improves, traditional floor finishes are still popular. “We’re seeing a lot of wax-oil hybrid finishes” in addition to oil and wax alone, says Kroupa, For example, at the Cracker Barrel restaurant chain, all front-of-house floors are finished with hardened oil. Easily maintained by staff with a renovator oil, the steady flow of heavy foot traffic actually rubs the oil into the wood, creating a hard patina and actually increasing durability with usage. “Natural oils and wax are a great option—retro and green at the same time,” says WXY’s Pew.
Resilient flooring. The choice of resilient alternative often depends upon client preference and the usage of the space. Linoleum is a popular choice because of its easy maintenance and green attributes. The composition is largely renewable materials: Lotz calls it “100% green,” and Baisch says it’s “the gold standard.” Both linoleum and rubber flooring offer durability, stain resistance, and acoustic dampening.
Rubber is specified frequently for institutional applications like schools and college facilities, and can be especially beneficial in healthcare settings. According to Hansen, “Rubber can provide foot comfort and back comfort, which is particularly advantageous where occupants are on their feet at length, like in an operating room.” She cautions, however, that rubber-flooring composition can vary. For a good selection, it must not contain recycled tires if it to be used indoors, since tires contain toxic chemicals and were not developed for use in building interiors. Recycled rubber flooring products now usually meet California 1350, “the most stringent IAQ test available,” notes Hansen. “But there are still issues with chemicals used in tire production, which could be released into the air and into occupants’ bodies as the flooring system degrades.”
Linoleum meets a number of initial sustainability considerations, although porcelain tile, ceramic tile, carpet tile, thin-set terrazzo, and cork (including rubber-cork blends) are all viewed as green alternatives by Building Teams. Materials that are typically described as cost-effective options are linoleum, porcelain, ceramic, and some precast terrazzo tiles. “We’re recommending more porcelain tile while the price is coming down due to the Italian market saturating the United States,” says Gensler’s Baisch. Cork, however, faces difficulty in competing on pure cost-effectiveness because it requires careful maintenance.
Many design professionals mention terrazzo tiles and epoxy coverings as excellent options in resilient flooring, although some caution that clients prefer to limit its use due to the upfront cost. “On the other hand, terrazzo will last forever and is easy to maintain,” says Franz, who calls it “the chameleon of floor covering,” in that the material can be precast or cast in place to create a wide array of styles and finishes.
Polished concrete. “Based on sustainability guidelines, I have recommended polished concrete as a low-VOC, low-maintenance option,” says QKA’s Quattrocchi. Polished concrete eliminates the need for an applied surface covering: using specialized polish tools, the concrete floor is beaten, ground, and rubbed until smooth and gleaming. Not every concrete floor is a candidate for polish, but those that are can be transformed into highly durable, low-maintenance surfaces. The sheen can be matte or glossy, and the concrete can be artfully dyed and designed before polishing.
The drawback with polished concrete is the structural concerns: settling and cracking. Though not likely to be a concern for slab-on-grade applications, a polished concrete floor will be unable to conceal any cracking. “We’ve never successfully specified it,” says Hansen. “Even if the client likes the aesthetic, we feel compelled to mention that it could crack,” she adds.
Polyurethane paint can serve as an economical coating for concrete and another alternative to coverings, adds WXY’s Pew.
Infection control. Certain commercial and institutional applications have gravitated toward flooring solutions that control bacteria, fungus, and other sources of infection. This is commonly done with resilient flooring that can be seamed when installed, to be effectively monolithic. Flooring products are often manufactured or installed with an added anti-microbial treatment, but the success and cost-effectiveness of these treatments are not fully verified. “Our extensive research into the topic suggests that by specifying it unnecessarily, we could be doing more harm than good,” says Hansen, with reference to her work in hospitals, labs, and higher education projects.
If there are no seams (or only carefully controlled ones), then a floor likely will not harbor or transfer infectious microbes. For this reason, commercial epoxy, vinyl, rubber, or linoleum are often specified in hospitals, laboratories, kitchens, schools, and daycare facilities. STUDIOS Architecture’s Krochmaluk points to a vinyl floor installed in a back-of-house food preparation area in a corporate project as an example. “We had success with a sheet vinyl product that can be rolled out and right up the wall to create an integral cove base,” he says. The joints can be heat-seamed to create a monolithic, microbe-resistant floor. Best of all, the integral base eliminates a typical area where food particles and dirt might collect, easing O&M needs.
Accessories. Flooring is never truly monolithic across a full building floor. There are joints and seams in places where one flooring type meets another, or where the flow of materials intersects with a dissimilar building system like a partition or door, thus creating potential aesthetic and maintenance difficulties. Ideally, transitions should always be flush and aesthetically seamless. Careful attention to joints also can pay off in enhanced client satisfaction.
“Where a corridor meets a restroom floor, the designer should give careful consideration to making a nice, effective transition,” says Hansen. Sustainable design principles are just as important when it comes to accessory components: metal and wood may be preferred over other materials, depending on their material makeup and maintenance requirements.
Some Building Teams give preference to flooring systems whose manufacturers provide products or guidance on suitable trim and joint detailing. Unfortunately, not all wood flooring manufacturers produce all the necessary trims, saddles, joints, and especially nosings (for stair landings and other drop-off points) to match every species, says Kroupa. These accessories may have to be fabricated in a mill shop, adding expense.
In terms of ADA-friendly and hazard-free interior designs, Building Teams may favor headers and feature strips to T-moldings, because flush joints eliminate tripping potential and may be preferred aesthetically. Another safety consideration: glare. “We try to avoid using thresholds with a high glare factor,” says Quadrangle’s Robbie. “They can be difficult for people with low vision to distinguish.” Building Teams should consult manufacturer literature and technical representatives to select appropriate accessories, joints, and trims, say experts.
OPERATIONS & MAINTENANCE: GROUND-LEVEL STAKEHOLDERS
Floors must be specified to meet the needs and likely habits of those who will clean and maintain them. Wherever possible, the facilities manager and even the operations and maintenance crew should be on the list for project communications, so that the floor can be maintained correctly from occupation through the life of the building.
Every building professional can offer a poignant example of maintenance-related flooring failure. “We specified cork floor, which worked well and looked great,” STUDIOS’ Krochmaluk recalls. “But a cleaning crew went at it with water and a wet mop. In no time at all the cork peeled off.” His recommendation for bigger projects with large facilities crews? “Keep it simple.”
Basic, durable, low-maintenance finishes are going to be preferable in most project types, according to the experts. Lotz suggests it is wise to assume that maintenance budgets are going to be underfunded, so Building Teams should specify with that reality in mind. The experience and attendant knowledge of the maintenance crew should also be assessed and factored into decisions about finishes.
Other operations and maintenance issues should factor in to questions of cost-effectiveness and long-term return on investment (ROI). “Vinyl resilient tile is seen as low-cost compared to rubber tiling,” says Robbie. “But the ongoing waxing and stripping requirements, versus simple damp-mop cleaning for rubber, can mean very high O&M costs.” The wood floors described earlier at Cracker Barrel restaurants offer a similar example: specifying prefinished wood may be less expensive up front, but a wood floor with an added finish that becomes more durable with heavy foot traffic (and simple maintenance) will likely present long-term cost savings.
Most designers agree that manufacturers bear some responsibility for communicating to the design team and to the facilities crew what is required to properly maintain the flooring. Rappoport even feels that the floor finish-material supplier is obliged to train the client’s cleaning staff in order to avoid a situation that could damage the installed finish.
There is also the question of sustainability and green design. Franz advises his clients, wherever possible, to use floor finishes made from natural materials, such as flamed stone, unfinished wood, and the like. These materials offer a beautiful aesthetic with low maintenance requirements, and can become more beautiful with age and wear, he says.
Others, including Hansen, strongly recommend finding out from the manufacturer if they have a green-cleaning protocol in place. “The products we specify have to be maintained for a very long time, even for the life of the building,” she says. “We want the flooring to last as long as possible, and we want the IAQ to be optimal for the building occupants and maintenance staff.” +
FURTHER READING REQUIRED
To complete the reading and take the exam to earn 1.0 AIA/CES learning units, go to www.BDCnetwork.com/CommercialFlooring.