Raised Floors
Raised floors provide a space for heating and air conditioning ducts, piping, electrical wiring, and computer cables. They are particularly useful in businesses where it is necessary to periodically add or rearrange computer workstations.What is a Raised Floor?
The supporting framework of a raised floor is a steel structure that is commonly between 12 and 18 inches high. (Depending on requirements, raised floors can be as low as four inches or as high as 24 inches above the underlying surface.) The floor itself is composed of small wooden panels laid on top of the steel framework. The panels rest in place and can easily be lifted to access the utility systems underneath. There are four classes of raised floors:
- Class 1 is used with light loads
- Class 2 is used with medium loads
- Class 3 is used with heavy loads
- Class 4 is used with special (very heavy) loads.
Drawbacks of Raised Floors
- Although useful, raised floors do have some drawbacks.
- Earthquake A raised floor makes it difficult to anchor equipment that may topple in an earthquake. The 1995 earthquake in Kobi, Japan demonstrated the vulnerability of raised floor systems to major buckling during a seismic event.
- Headroom In rooms with low ceilings, the loss of headroom due to a raised floor may be unacceptable.
- Fire Codes A raised floor is considered to be a special fire risk. Consequently, cables run under the raised floor must be enclosed in a metal or fire-rated polymer conduit. This adds considerable cost and makes it more difficult to reroute cables when needed.
- Cleaning The space under the raised floor accumulates dust and dirt and is impractical to clean.
- Safety Maintenance procedures often require that one or more floor panels be left open while work is proceeding. If the area is not properly cordoned off, a serious safety hazard may be created.
- Security Devices or people may be concealed underneath a raised floor, or the floor may be used as a way to access secure areas.
- Cost Raised floor systems are expensive, costing $20 or more per square foot.
Another Type of Raised Floor
The term raised floor is also used to describe home construction where the house is raised off the concrete slab or underlying ground by wood framing. There are several reasons for incorporating a raised floor into new home construction:
- Accessibility The plumbing, electrical, and mechanical systems of the house are installed between the slab or ground and the raised floor and can be accessed via a crawlspace.
- Ease of Repair All foundations tend to settle over time. A raised floor makes it easy to repair minor cracks caused by settling and re-level the foundation.
- Comfort An insulated raised floor minimizes heat loss and makes the home more comfortable.
- Water Protection A raised floor may be a practical solution to building a home in a flood-prone area.
- Beauty A raised floor gives a house greater stature and enhanced curb appeal.