Food Service. In many older Federal buildings, dining
Utility distribution in historic buildings is the most
areas are located below grade in cramped, poorly venti-
difficult because ceilings and floors often have to be
lated, poorly lit, and publicly inaccessible spaces. Major
preserved or restored. In these cases, decentralized air
renovations are a good opportunity to correct this
conditioning units with little or no ductwork become
situation.
feasible. Pre-wired systems furniture, which is available in
wood, is also a very good solution.
Placement of Main Mechanical and Electrical
Equipment. If new equipment is to be placed on the roof,
Office Space. Where existing office space is altered to
the structural capacity of the framing system must be
an open plan, noise isolation of the ceiling system
investigated.
should be a minimum of NIC 20. Noise isolation class
between rooms should be NIC 40 in Class B spaces and
Elevators. For complete building renovations a
NIC 35 in Class C space. See the section Special Design
transportation study should be done, as described earlier
Considerations, Acoustics, Design Criteria for Building
in this chapter. If elevators need to be replaced, service can
Spaces of this chapter.
often be improved significantly by selecting higher speed
elevators to fit into the existing shafts. New shafts are
Historic Buildings. Hard surfaces often predominate in
expensive to build and should be avoided.
old buildings and create resonance and echoes. While it
may be possible to upgrade the acoustical environment,
Space Planning Strategies
this should not be done at the expense of the historically
significant features of the building.
Office Space. It may be necessary to design a slightly
larger space allocation - about 12 m2 (135 square feet)
Alteration of Building Elements
per person - for office layouts in older buildings. This
compensates for less than ideal bay sizes and existing walls
Exterior Closure. See Chapter 4: Structural Engineering,
configurations. The planning standards described earlier
Alterations in Existing Buildings. Most older buildings lack
in the section Space Planning, should be used as much as
adequate insulation and vapor barriers, but these can be
possible.
added from the inside at the time of alteration. Design
alterations to avoid damaging original finishes in
Pre-wired systems furniture may be an appropriate
preservation zones (as defined in the BPP or HSR).
solution for distribution of power and communications
wiring in renovated buildings. Open plans have been used
Refer to Building Elements Section of this chapter for
successfully in historic buildings. Furniture systems must
references regarding treatment of existing windows.
be selected with great care to minimize any adverse
Exterior masonry should be cleaned if necessary and
impact on the historic features of the building. Modular
repointed. Joints should be resealed.
furniture system dimensional planning restrictions, best
adapted to large open office areas, may have limited
Re-roofing. Where existing roofing is to be replaced, it
feasibility in older structures with short or irregular
should be completely removed and the substrate prepared
structural spans.
103
ARCHITECTURAL
AND
INTERIOR
DESIGN
3.8
Alterations in Existing Buildings and Historic Structures
Revised March 2005 PBS-P100
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