Heads up:
There are no amended sections in this chapter.
Additions to any building or structure shall
comply with the requirements of the VCC for new
construction without requiring the existing building or
structure to comply with any requirements of those codes
or of these provisions, except as required by this chapter.
Where an addition impacts the existing building or
structure, that portion shall comply with this code. Where
a fire wall that complies with Section 706 of the VCC is
provided between the addition and the existing building,
the addition shall be considered a separate building.
An
addition shall not create or extend any nonconformity in
the existing building to which the addition is being made
with regard to accessibility, structural strength, fire
safety, means of egress, or the capacity of mechanical,
plumbing, or electrical systems. Alterations to the
existing building or structure, shall be made so that the
existing building or structure, together with the addition
are no less conforming to the provisions of the VCC than
the existing building or structure was prior to the
addition.
Any repair or alteration work within
an existing building to which an addition is being made
shall comply with the applicable requirements for the
work as classified in this code.
No addition shall increase the
height of an existing building beyond that permitted
under the applicable provisions of Chapter 5 of the VCC
for new buildings.
No addition shall increase the
area of an existing building beyond that permitted under
the applicable provisions of Chapter 5 of the VCC for
new buildings unless fire separation as required by the
VCC is provided.
Exception: In-filling of floor openings and
nonoccupiable appendages such as elevator and exit
stairway shafts shall be permitted beyond that
permitted by the VCC.
Additions to existing
buildings or structures are new construction and shall
comply with the VCC.
Any existing gravity load-carrying structural
element for which an addition and its related alterations
cause an increase in design gravity load of more than 5
percent shall be strengthened, supplemented, replaced or
otherwise altered as needed to carry the increased gravity
load required by the VCC for new structures. Any
existing gravity load carrying structural element whose
gravity load-carrying capacity is decreased shall be
considered an altered element subject to the requirements
of Section 603.7.3. Any existing element that will form
part of the lateral load path for any part of the addition
shall be considered an existing lateral load-carrying
structural element subject to the requirements of Section
803.3.
Exception: Buildings of Group R occupancy with no
more than five dwelling units or sleeping units used
solely for residential purposes where the existing
building and the addition comply with the
conventional light-frame construction methods of
the VCC or the provisions of the International
Residential Code.
Where the addition does
not result in increased design live load, existing
gravity load-carrying structural elements shall be
permitted to be evaluated and designed for live loads
approved prior to the addition. If the approved live
load is less than that required by Section 1607 of the
VCC, the area designed for the nonconforming live
load shall be posted with placards of approved
design indicating the approved live load. Where the
addition does result in increased design live load, the
live load required by Section 1607 of the VCC shall
be used.
Where the addition is structurally independent of
the existing structure, existing lateral load-carrying
structural elements shall be permitted to remain
unaltered. Where the addition is not structurally
independent of the existing structure, the existing
structure and its addition acting together as a single
structure shall be shown to meet the requirements of
Sections 1609 and 1613 of the VCC. For purposes of this
section, compliance with ASCE 41, using a Tier 3
procedure and the two-level performance objective in
Table 305.2.1 for the applicable risk category, shall be
deemed to meet the requirements of Section 1613.
Exceptions:
- Any existing lateral load-carrying structural element whose demand-capacity ratio with the addition considered is not more than 10 percent greater than its demand-capacity ratio with the addition ignored shall be permitted to remain unaltered. For purposes of this exception, comparisons of demand-capacity ratios and calculation of design lateral loads, forces and capacities shall account for the cumulative effects of additions and alterations since original construction. For purposes of calculating demand capacity ratios, the demand shall consider applicable load combinations involving VCC-level seismic forces in accordance with Section 305.2.1.
- Buildings of Group R occupancy with no more than five dwelling or sleeping units used solely for residential purposes where the existing building and the addition comply with the conventional light-frame construction methods of the VCC or the provisions of the International Residential Code.
Voluntary
addition of structural elements to improve the lateral
force-resisting system of an existing building shall
comply with Section 603.7.5.
Any structural element of an
existing building subjected to additional loads from the
effects of snow drift as a result of an addition shall
comply with the VCC.
Exceptions:
- Structural elements whose stress is not increased by more than 5 percent.
- Buildings of Group R occupancy with no more than five dwelling units or sleeping units used solely for residential purposes where the existing building and the addition comply with the conventional light-frame construction methods of the VCC or the provisions of the International Residential Code.
Additions and foundations in
flood hazard areas shall comply with the following
requirements:
- For horizontal additions that are structurally
interconnected to the existing building:
- If the addition and all other proposed work, when combined, constitute substantial improvement, the existing building and the addition shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
- If the addition constitutes substantial improvement, the existing building and the addition shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
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For horizontal additions that are not structurally
interconnected to the existing building:
- The addition shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
- If the addition and all other proposed work, when combined, constitute substantial improvement, the existing building and the addition shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
- For vertical additions and all other proposed work that, when combined, constitute substantial improvement, the existing building shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
- For a raised or extended foundation, if the foundation work and all other proposed work, when combined, constitute substantial improvement, the existing building shall comply with Section 1612 of the International Building Code, or Section R322 of the International Residential Code, as applicable.
- For a new foundation or replacement foundation, the foundation shall comply with Section 1612 of the International Building Code or Section R322 of the International Residential Code, as applicable.
