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Assisted Living Construction Methods for Clean FacilitiesBy Andrew E. Glassford
The most common structural systems used in multi-story buildings are wood frame, masonry bearing precast floor, metal stud with cast concrete deck, structural steel composite with cast concrete deck and concrete column concrete deck. Regional familiarity and resources have an impact on the economic benefit with each of the systems. Certain labor markets may be more productive and cost-effective with a wood frame system, which has a significantly shorter production time than a structural steel system. Structural steel, which allows greater spans and offers flexibility for open areas, can have a manufacturing period of 12 to 16 weeks. Cast-in-place concrete structures have a significant cost benefit in structures taller than five stories, when productivity increases are realized in total cost efficiency. The construction schedule can also affect the system cost. In northern climates, winter weather can add significant dollars. Wood frame is least impacted, followed by metal stud/concrete deck, then structural steel, cast concrete and finally, masonry bearing precast, which is the least cost effective for a winter construction schedule.
Masonry bearing precast tends to have the next greatest movement potential. This system uses a stacking method of dissimilar materials that can have an extended settlement period. The drywall can experience significant movement as well. Structural steel frame and metal stud with concrete deck offer a more stable substructure for drywall. The static nature of steel and concrete lend well to their use as a substrate in minimizing future movement. Structural concrete, in which each floor is integrally tied with the same material, has the best settlement and acclimatization benefit. Minimal drywall movement is experienced in an all-concrete structure. Drywall separation can be minimized with the use of control joints at door openings and other locations throughout the building. It is important to coordinate their use during design and construction, as they are often missed. Some architects and owners do not like the aesthetic impact of a control joint; however the neat line the control joint offers has a much better maintenance and future appearance than the repeated patching or caulking of a drywall crack. The use of wood trim in a facility is another factor that affects overall hygiene. Base, door casings, chair rails and cornice can also experience shrinkage and separation over time as the wood acclimates to its new environment. Use of medium density overlay board (MDO), a wood composite with minimal moisture content, for wood trim eliminates the separation caused by shrinkage. MDO can be limited in its application, as its appearance requires it to be painted in lieu of staining. MDO would not be suitable if a wood grain finish is desired. One key element used in order to control infection is the selection of flexible finishes. While not as aesthetic, vinyl flooring and fiberglass reinforced plastic (FRP) wall panels can offer greater flexibility and moisture resistance than ceramic or quarry tile. Hard tile's nature as a composite system with multiple joints and grout invite cracking and separation, as well as offering a porous environment for accumulation. Properly maintained, hard tile can offer the same resilience as vinyl or FRP, but the ability to properly manage cracks can be a challenge. It is important to consider how building materials and structural systems can impact the ability to sustain the necessary sanitary environment of an assisted living facility. While cost benefits must be viewed on a regional basis, labor familiarity, availability and weather all affect the feasibility of the building structure. Allowance for movement in the design and construction will minimize any cracking in drywall and finish materials. Additionally, selection of flexible finishes will also help maintain cleanliness and reduce risks of spreading illness in an assisted living facility. Drew Glassford is a Project Director with Novak Construction Company, a Chicago area general contractor. Mr. Glassford has more than 20 years of industry experience, including management of the construction of more than 30 assisted living and multi-unit residential facilities in the United States and Canada.
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When
planning a new assisted living facility, the type of construction can have an
impact on the maintenance and cleanliness of the building. Structural
composition and building materials contribute greatly to the ability to control
and minimize potential threats of infection in a facility.
For
maintaining cleanliness of a facility, wood frame has the least benefit of the
five systems. The nature of wood as a "live" building material
contributes to a significant building adjustment period, during which drywall
separation becomes apparent. Corners and beams can shift and crack more in a
wood frame structure as the wood dries and settles. This movement creates not
only a maintenance issue but also creates areas of refuge for debris and
bacteria.
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