April 6, 2017
by Casey Ball
Specifying either a new or renovated flooring system for a commercial building often comes down to the quoted cost of the materials and labor needed to complete the job. However, that final quote is never the best measure of the floor’s true cost to the building owner—rather, it is just the check amount written to the contractor. The actual cost includes much more.
First, the building owner must be prepared for some downtime related to the flooring installation. No one will be able to walk through the area for a given period, halting progress on other work. Depending on conditions, contractors may need to take extra time to set up containment systems to eliminate airborne contaminants and mitigate odors. Ultimately, the faster the coating is applied and the sooner it dries and cures, the sooner everyone can resume normal operations. Anything a specifier can do to speed up these processes, such as recommending a fast-cure flooring system, can help minimize downtime and its associated costs.
The labor required to complete a job can also vary based on the chosen flooring. Specifiers can influence efficiencies and cost reductions by recommending products that are easier to install. The final crew size is the contractor’s decision, but if the specified product can help reduce application time, the project can achieve significant worker-hour savings.
The longevity of the flooring system and its repairability, however, are the primary indicators of its total cost of ownership. If the coating scuffs easily or if it is prone to deterioration when exposed to chemicals, maintenance crews will be busy making repairs, leading to more downtime and increased costs. Additionally, the sooner a building owner has to replace a floor, the greater its life-cycle costs. By recommending a system that offers durability, specifiers can help reduce maintenance needs, delay flooring replacements, and ultimately reduce expenditures.
Considering these ‘hidden costs’ provides a much clearer picture of a floor’s true price, and how to select the best system for a given project. However, one must also recognize swapping one flooring type for another can come with some tradeoffs—for example, faster installation might also mean higher odors. Surprisingly, it may be more cost-effective to install flooring that is more expensive upfront because its various downtime requirements and life-cycle costs are less than with a system with a lower initial expense. This article reviews several flooring types, outlining their potential hidden costs.
Minimizing operational downtime
Downtime is the scourge of any operation, as it can lead to increased costs, production delays, and lost revenue. However, ‘down’ need not mean ‘out’ with flooring installations. Specifiers have the capability to help contractors and building owners realize faster return-to-service times via their product recommendations.
Installing or repairing a resinous floor requires downtime interfering with the productivity of other operations. Flooring systems go down wet, which means other trades and/or facility personnel will need to stop work and avoid the area to prevent contamination. They will not be able to re-enter until the applied flooring dries sufficiently to handle foot traffic—they may have to wait even longer (typically twice or threefold as long) for it to cure adequately to support equipment traffic.
Available flooring systems include a wide array of technologies featuring varying levels of application efficiencies, curing times, durability, repairability, and other characteristics. (See “Getting to Know Resinous Flooring,” for a rundown of common choices and their respective properties.)
Based on the desire to reduce downtime, some design professionals assume it
is critical to simply specify a flooring system with the fastest installation and curing times. However, the real best bet is to find a balance of desired properties related to the project requirements.
For example, if one only has a four-hour shutdown to complete an installation, a methyl methacrylate (MMA) floor may be the sole suitable choice. However, MMAs can present flammability and odor concerns. If a buffer of even a few extra hours is available for the installation, specifying a polyaspartic (PAE) floor could be a better fit, as it trades some of the speed of an MMA for greatly reduced odors. When there is an opportunity for an even longer installation window, the product choices open up to include dozens of options, each with its own property tradeoffs related to speed, cost, and durability.
Waiting out concrete-curing times
Potential downtime associated with flooring installations actually begins the moment contractors finish pouring the concrete substrate. The concrete needs to cure at least 28 days before most flooring types can be installed—the moisture vapor content must drop to acceptable limits for proper adhesion. Other facility work can take place in the interim, but crews cannot apply flooring products like a traditional epoxy system until at least four weeks after the concrete pour.
During this wait, other work, such as the placement of equipment and floor cabinetry, may reach a stopping point until crews can install the floor. However, specifiers can accelerate the entire process by recommending a floor allowing for application over ‘green’ concrete. For example, urethane concrete floors are highly tolerant to moisture, which allows crews to apply them over fresh concrete in as little as three to five days following the pour. This option would allow installers to apply urethane concrete at least 23 days sooner than a traditional epoxy, which could greatly speed up construction timelines and reduce downtime.
Accelerating project schedules can be especially important when renovating facilities. For example, if a renovation calls for adding a new electrical trench, the relatively small area of new concrete poured to cover the trench could cause a month’s delay before crews are able to install the flooring system. Using a moisture-tolerant floor would cut that time down to days, allowing the renovated area to return to service much sooner.
Accelerating flooring curing times
The steps required to apply a flooring system depend on the amount of coating layers needed before topcoating. While this number certainly has some bearing on project length, the curing times associated with each layer have the greatest influence. If a particular layer cures rapidly (e.g. a primer taking two hours), the contractor may be able to apply the next layer the same day. This efficiency could mean the difference between a crew completing the whole project in one or two visits and needing to return to the site multiple times.
To enable more efficient installations, specifiers can recommend flooring options that have faster cures for each applied layer. The installation of epoxy mortar versus urethane concrete for a 930-m2 (10,000-sf) facility using a five- to seven-member crew provides an example. Figure 1 details the full installation times of epoxy mortar (more than 100 hours) and urethane concrete (52 hours when using the optional primer).
The epoxy mortar floor requires one additional step that adds to the project length, but the curing times represent the greatest time sinks. Calculating the curing times shows a difference of 42 hours between the systems and a major disparity in their contributions to project downtime—60 hours of curing time (or about 60 percent of the project downtime) for the epoxy mortar and 18 hours (or about 35 percent of the downtime) for the urethane concrete. Further, urethane concrete allows full service within six to 12 hours of topcoating, compared to 24 hours for epoxy mortar, allowing the facility to resume operations at least a half-day sooner.
Odor mitigation needs can also contribute to increased downtime. Depending on the flooring choice, the contractors may need to set up a negative-pressure containment assembly to ensure worker safety during installation. Such systems contain and capture indoor air particles and odors to minimize air toxicity and reduce flammability potential.
To set up a containment system, workers must construct a physical barrier separating the work area from the rest of the facility and seal off any HVAC return air vents. They must then set up fans and high-efficiency particulate arrestance (HEPA) filtration devices to introduce clean air and exhaust dirty air. These steps all take time, adding to facility downtime and project costs. Specifiers may wish to reduce that added downtime and cost by substituting MMA with PAE, for example, to eliminate the need for an odor mitigation system.
Odor mitigation is especially critical in renovation projects, as the building may be occupied during the flooring installation. This may necessitate night, weekend, and/or holiday work, adding to labor costs. The same may be true for new construction projects, so flooring installers do not affect the health and safety of other trades working on the building.
Surprisingly, the odor of a flooring system has very little to do with its level of volatile organic compounds (VOCs) or with a project’s ability to earn points under the Leadership in Energy and Environmental Design (LEED) program. One would expect a low-VOC system to have low odors, but this is not necessarily the case—MMAs have a pungent odor, but can have zero VOCs. Specifiers should check with their manufacturer’s representative to determine the odor potential of a product, but they can view VOC information directly on data pages. The most common credit for resinous flooring is LEED 4.2, Low-emitting Materials: Paints & Coatings, which sets a maximum limit of 100 g/L VOCs for floor coatings. Most of the available flooring systems are high solids formulations that meet this restriction and will qualify for one point under LEED 4.2.
Keeping labor costs in check
While the contractor has the final say on how many crew members to use for a given job, specifiers can influence labor efficiencies by recommending flooring that is easier to install. Systems with fewer application steps and/or faster cures can help reduce labor needs for a project. However, the installation’s size, scope, and complexity have the most impact on labor requirements. Site supervisors and general contractors can help reduce labor needs here by strategically scheduling trades so the flooring installation occurs before any obstacles are set in the way. For example, installing a floor system for a public restroom at an educational institution requires more time and labor if the stall partitions are already in place and the flooring contractor needs to cut in around the legs of each partition.
|GETTING TO KNOW RESINOUS FLOORING|
|For the four main flooring system chemistries, critical performance characteristics can be compared using a good-better-best scale. Each characteristic contributes in some way to the downtime, labor, and longevity factors comprising the true costs of a floor. The systems can be applied over existing resinous flooring with minimal risk, although crews will need to carefully clean, degrease, and mechanically prepare the existing system to ensure adhesion of the new system. Still, there is some risk the original system was improperly applied, meaning it could lift off the concrete substrate even if the new application adheres to the original system.
Promoting longevity to reduce costs
A specifier can have the greatest impact on reducing the hidden costs of a flooring system by selecting products that offer long life cycles. That means specifying materials with high resistance to moisture, abrasions, thermal shock, chemicals, and additional factors relevant to the application. A system’s long-term durability, along with its ease of repair, reduces maintenance needs and delays complete flooring replacements.
Of course, specifiers must still balance property tradeoffs (e.g. swapping long-term durability for installation ease) as they consider project time constraints and life-cycle costs. For example, specifying a floor with a faster upfront installation but lower durability, such as a thin-mil system, could mean replacement every five years, which raises life-cycle costs. When a 3.2-mm (1/8-in.) system is called for, it may be more expensive upfront, but it might only require a topcoat every five to 10 years. This would be far more cost-effective over time.
When weighing product decisions based on durability, specifiers may need to overcome some common misconceptions about product performance data. For example, many specifiers believe the harder the flooring, the greater its abrasion resistance. Therefore, they may specify an epoxy system because it has a Shore D hardness of 90, compared to a urethane coating with a 6H pencil hardness. However, because they are softer, urethane coatings actually have three to five times the abrasion resistance of epoxies.
Compressive, tensile, and flexile strength are other properties that many specifiers misunderstand. For example, a design professional may automatically choose an epoxy system with a compressive strength of 82.74 MPa (12,000 psi) over its 48.26 MPa (7000-psi) urethane concrete counterpart because the bigger number sounds better. However, it is important to remember either system will be applied to a concrete substrate, which has a compressive strength of only about 27.58 MPa (4000 psi). It can actually be advantageous to select the urethane concrete because a system with a compressive strength that is closer to that of concrete is less likely to debond from the concrete when subjected to thermal shock. The urethane concrete’s flexibility allows it to move more uniformly with the concrete as it shifts from temperate cycling due to thermal shock. Since a more rigid epoxy cannot move as easily with the concrete, it would be more prone to delaminating from the concrete substrate.
Specifying a flooring system
The true cost of a floor includes much more than the expense of materials and labor. Specifiers need to consider the downtime associated with all aspects of the project, whether any installation efficiencies are possible, and how long they can expect the flooring to last to determine the complete life-cycle costs of a system. Examining these parameters against various systems could expose several tradeoffs—such as faster installations, but lower durability—that may complicate the selection process. To alleviate confusion, specifiers can work with a specialized flooring provider to sort through potential scenarios associated with an installation, repair, or renovation to arrive at the appropriate product choice. This may help specifiers avoid choosing the least-expensive option upfront when it may have significantly higher life-cycle costs.
|RESINOUS FLOORING APPLICATION CONSIDERATIONS|
|Specifying a resinous flooring system involves a wide range of considerations. Here are a few application characteristics to keep in mind.
Application to green concrete
Removal of existing floors
If an existing system needs to be removed, crews have to peel it off and then remove any remaining glues and curing compounds via chemical and/or mechanical means. For example, crews may need to use citric acid to soften and remove glue, and they may need to shot-blast, grind, mill, or even scarify the surface to fully remove the adhesive and get the surface to a smooth finish. In extreme cases, a flooring renovation will require breaking up the concrete base and pouring a new substrate.
Addressing termination points
Casey Ball is regional market segment director of flooring for Sherwin-Williams Protective & Marine Coatings. He previously served as a project development manager, drawing on his experience as a corrosion specification specialist and a technical service representative for Sherwin-Williams after starting his career as a lab technician at General Polymers. Ball has specialized in the flooring and coatings market for 15 years. He is a NACE-certified coatings inspector, and a Society for Protective Coatings (SSPC)-certified concrete coatings inspector. Ball can be reached via e-mail at email@example.com.
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