ENVELOPE
4-4
.
4-4.1 GENERAL:
E n v e l o p e refers to the combination of opaque and
transparent materials that sheath the building exterior. The envelope
m a y be entirely non-load-bearing or portions of it may form the vertical
structure of the building.
T h e envelope may be entirely fixed or portions
m a y be movable in the form of operable sash or ventiIation louvers.
T h e prime function of the envelope is to provide a
4-4.2 FUNCTIONS:
weatherproof,
durable protection to the building exterior.
In addition;
t h e envelope provides insulation to the interior from outside ambient
t e m p e r a t u r e and solar heat gain.
4-4.3 ENERGY CONSERVATION: T h e envelope is a major source of heat gain
Heat gain and loss must be compensated
or loss to the building interior.
f o r by the air-conditioning and heating systems, and inadequate insulation
or excessive solar heat gain through glass will result in greatly
i n c r e a s e d energy usage, and consequent operating cost increase.
For this
r e a s o n the extent, type and location of glass, and the proposed materials
s h o u l d be carefulIy reviewed with the mechanical engineer as design
proceeds.
4-4.4 APPEARANCE:
T h e envelope is a major determinant of building
appearance.
Besides the familiar attributes of form, color and texture,
a p p e a r a n c e is heaviIy influenced by maintenance.
Materials that weather
well
and require little maintenance wiII be of overalI benefit to the
building
appearance.
Maintenance costs of all exterior materials should
b e c a r e f u l l y c o n s i d e r e d , n o t only as an aspect of life cost, but because
h i g h maintenance cost may result in insufficient maintenance of the
b u i I d i n g exterior and consequent deterioration of appearance.
4-4.5 ENVELOPE DESIGN ALTERNATIVES
4-4.5.1 Poured-in-place Concrete: (1)
Usually performs a structural function.
Finishes include:
A. I n t e g r a l F i n i s h : N a t u r a l ,
e x p o s e d aggregate, bush-
hammered, s a n d - b l a s t e d ,
flat,
fluted, sculptured, etc.
B. A p p l i e d F i n i s h : M a s o n r y v e n e e r ,
c e r a m i c veneer, plaster, water
proofing, painted surface, etc.
4-13
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