Following guidelines that have already proven to be effective in similar projects can help designers and contractors avoid common pitfalls pertaining to construction materials used for flooring, walls, and ceilings. The Association of Assessment and Accreditation for Laboratory Animal Care (AAALAC) in Rockville, Md., estimates that 13 percent of all deficiencies in animal research facilities can be attributed to the physical plant. Therefore, using materials that are resistant to moisture, chemicals, and heavy impact is especially important.

Although 13 percent may seem small, AAALAC states that 70 percent of the deficiencies can be traced back to institutional policies such as revising protocols. However, problems related to the physical plant typically have large ramifications in terms of additional construction, cost overruns, and productivity downtime. Revising a protocol pertaining to the institutional policy, on the other hand, is relatively easy and usually does not result in construction cost overruns or significant downtime.

Key Considerations When Selecting Materials

Key issues must be reviewed when deciding what type of floors, walls, and ceilings will be used in the construction of a new animal research facility or the renovation of an existing building.

"There are a lot of different systems available for selection when designing facilities. The most important thing is attention to detail," says Stuart Lewis, laboratory designer in the Atlanta office of HOK. "No matter how good the systems are, the detailing in design and construction is critical."

The first issue to take into account is function based on where the material will be used. For example, will it be used in a cagewash area, a storage room, or a lab where chemicals are used? Answering these questions will help planners determine what level of chemical resistance is required, what kind of load capability is necessary, and how much slip resistance will be needed.

Maintenance of the selected materials should also be figured into the planning process. What type of cleaning will be required and how often will maintenance be necessary? Operating costs and budget are also key considerations. The amount of money built into the budget for maintenance, renovation, and replacement costs will be a key factor in deciding whether to use a more expensive product or to opt for a cheaper material until the money is available to upgrade.

"The cost of the system goes up with its increased level of performance," notes Yvonne Foucher, laboratory designer and architect in the St. Louis office of HOK. "What kind of budget do you have and what is the maximum system that you can afford to buy to meet your requirements?"

Other items that must be figured into the design process are schedule, preferences, and experience or familiarity. Schedule plays a significant role in the selection process because the types of materials used for a renovation project are likely to differ from those chosen for a new facility.

"Schedule impacts us quite a bit because if you are talking about a new facility, maybe you have two or three weeks to do an installation," says Foucher. "If you're renovating an existing facility and can't afford the downtime that will impact your system selection, as well."

Preferences and experience equate to using what you like in order to achieve the desired look for the facility, whether it will be user-friendly or a more industrial environment. Planners often use the type of materials that have worked for them in the past and avoid those that have resulted in poor performance or other bad experiences. Poor performance may be attributed to a poor installation or inexperienced installers as opposed to a fundamental problem with the product.

"There are a million products out there so you really need to simplify the selection process," advises Foucher. "First, figure out what product or combination of products will meet your needs and then do your own test of the material before final selection."

Selecting the Right Type of Floor

The floor system is only as reliable as the base beneath it, making it important to choose the most appropriate substrate for each area of the facility. The most common substrate materials are concrete and concrete over a metal deck, the latter of which tends to retain water and, therefore, may take longer to cure. Plywood is used primarily as a substrate in mobile units because it is lightweight.

"When specifying the concrete mix, you want to ensure that you are using a low water-cement ratio in the concrete. The more water you put in as it cures and evaporates, the more voids are created, which means you now have more concrete that you have to protect," says Foucher. "Using a lower water-to-cement ratio, known as 'low slump concrete,' is more difficult to work with, but provides a better substrate."

Coatings are a thin film protectant for concrete, providing additional durability and chemical resistance. It also seals the concrete from penetration by chemicals and biological matter. The disadvantages are that coatings are more easily damaged, wear off with light pallet traffic, provide minimal protection of the substrate, and do not hide surface imperfections in substrate. Coatings cost an average of $1 to $2 per sf.

Slurry is a self-leveling resin-base coat with the option to include color chips. The flexible system bridges minor surface defects and can be used in coolers. However, it is difficult to apply on sloped substrate and damages easily. Costs are between $5 and $8 per sf.

Methylmethacralate (MMA) is a self-leveling acrylic resin-based coating with the option to include color, priced at $13 to $16 per sf. It is difficult to apply because it cures quickly and produces a very offensive odor requiring good ventilation.

Trowel down systems, which are a resin and aggregate mortar with a protective coating, is more impact-resistant, but requires more skill to install and is more expensive at $7 to $12 per sf.

Rubberized finishes, which should not be used in areas of high moisture, are a resin and rubber aggregate mortar with a protective coating. This relatively new system rates high for being impact- and chemical-resistant, but tends to be the most expensive finish at $15 to $20 per sf.

"I believe the no-VOC system is the number one product and the future of floor finishes," says Foucher. "If you are trying to become LEED™-certified, this product will help get you points because it is a green product. It's part of the future of saving the environment by not releasing these harmful elements into the atmosphere."

No-Volatile Organic Chemical (VOC) systems range from $9 to $11 per sf.

Guidelines for Walls and Ceilings

Walls should have the same qualities as the floors, including a smooth finish that is resistant to moisture and impact. Walls must be easy to clean and free of imperfect junctures with sealed penetrations that do not allow contaminants into the room.

There are four types of wall substrates, including water-resistant gypsum board, cement board, masonry and composite panels. Gypsum board is the least preferable because it is not impact-resistant and the downside of the composite panels is the visibility of seams. While masonry is the traditional construction type, cement board is becoming more common in animal facilities.

Wall finishes range from coatings, reinforced coatings, and flexible coatings to trowel down and composite panel systems. The composite panels are the most expensive, averaging between $12 and $14 per sf, while coatings are the least expensive, costing between $1.50 and $3 per sf with the others falling in the middle price range.

"Don't use paint in any animal facility; you want a coating," says Foucher. "You want a two-part system because you are going to get increased chemical resistance, as well as better adhesion and durability for the cleaning abuse and the things that inherently happen in an animal facility. The flexible coatings are a new product that I believe will be the future in wall systems. They put elastomizers in the epoxy coating to allow it to stretch and bridge cracks up to 1/16" wide."

The recommended guidelines for the ceilings are nearly identical to those for walls with the exception that masonry would not be used as a substrate and the materials do not have to be as impact-resistant.

Selecting Doors and Hardware

"The main characteristics you need in doors and hardware is that they are durable, chemically resistant, and can be scrubbed, but the key quality in our experience is the vermin-proof requirement," says Lewis. "It is recommended that the top of the door be welded flush with a C-shaped piece of metal, as well as tightly sealed around the perimeter."

Doors must be corrosion-resistant, durable, and impact-resistant. They must be free of cracks and crevices that could allow vermin access to the interior of the door or harbor bacterial growth. All penetrations should be sealed and protective devices, such as kick plates and jamb guards, should be used to protect the structural integrity of the door.

Stainless steel doors are highly recommended, although they are more expensive than traditional hollow metal doors.

Final Thoughts

After selecting the best products, an appropriate contractor with the necessary installation skills must be chosen.

"The majority of failures happen during the installation and not as a result of the products," says Foucher. "Be sure to specify that the contractor has to be experienced in the type of installation you need."

The contractor should demonstrate a minimum of five years of experience with a particular system. The experience can be verified by asking for and later calling references.

"The contractor is going to give you the names of people who will say great things about his best installations," adds Foucher. "Tell him you also want the name of one person who can talk about a failure, a project that went south on him. Call those people and find out how the contractor performed during this kind of stressful situation. You want a contractor who will be able to respond to problems. You need to protect yourself."

By Tracy Carbasho

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