South Carolina Code of Regulations › Chapter 79 - DEPARTMENT OF LABOR, LICENSING AND REGULATION- MANUFACTURED HOUSING BOARD › Section 79-42 - Manufactured Home Installation Requirements

Current through Register Vol. 48, No. 6, June 28, 2024
A. Scope and Applicability. All new
		  manufactured homes in the State of South Carolina must be installed per the
		  Manufacturers Installation Instructions or in the event the Manufacturers
		  installation instructions are not available for a new home, the home must be
		  installed per the requirements of 24 CFR Part 3285. All used manufactured
		  homes, without manufacturers installation instructions, shall be installed per
		  the requirements of this Section. The Manufacturers Installation Instructions
		  and the requirements of this Section shall preempt any existing local standard.
		  (See paragraph G).
B. Manufactured
		  Home Installation. The Federal Manufactured Home Construction and Safety
		  Standards Program ( 24 CFR 3280, 3282 and 3285 ) requires that all manufactured
		  homes be provided with installation instructions covering foundation,
		  anchoring, utility connections, and other items. Where such installation
		  instructions are provided, they shall be followed and supplemented by this
		  regulation. In the event that conditions exist that do not meet, or are not
		  covered in, the Manufacturers Installation instructions, or the installer
		  chooses an alternative design for an installation, any alternative design must
		  be prepared by a design professional and approved by the manufacturer and its
		  Design Approval Primary Inspection Agency (DAPIA) before the home is set.
1. Foundation Systems for Manufactured Homes.
		  A Manufactured Home Foundation System is one constructed in accordance with the
		  foundation system included in the manufacturer's installation instructions,
		  supplemented by the requirements of these regulations. The manufacturer or
		  homeowner shall be permitted to design for unusual installation not provided
		  for in the manufacturer's standard installation instructions, provided a
		  licensed professional engineer or architect approves the design in writing.
		  When the manufacturer's instructions are not available, Table 1 in Appendix A
		  indexes information for the design of manufactured home foundation systems
		  which meet the minimum criteria established in this regulation.
2. Manufactured Homes with Manufacturer's
		  Instructions. The manufacturer's instructions include a typical foundation
		  system designed by a registered professional engineer or architect to support
		  the anticipated loads specified in the manufacturer's installation instructions
		  for the design zone (including climate) of installation, and shall meet the
		  requirements of these regulations. These instructions shall be provided with
		  the home following installation as required by 24 C.F.R., Parts 3280, 3282, and
		  3285( 42 U.S.C. 5401 et seq.).
3.
		  Manufactured Home Stabilizing Devices and Design. Each manufactured home, upon
		  being installed on a manufactured home stand, shall have stabilizing devices,
		  or shall be installed on a foundation constructed in accordance with the South
		  Carolina Residential Code. Stabilizing devices not provided with the
		  manufactured home shall be listed or labeled to meet or exceed the design and
		  capacity requirements of the manufactured home manufacturer's installation
		  instructions and these regulations.
a.
		  Anchoring.
(1) Each manufactured ground anchor
		  shall be listed and installed in accordance with the terms of its listing and
		  the anchor manufacturer's instructions and shall include means of attachment of
		  ties meeting the requirements of paragraph (B) (3) (b) (v). Ground anchor
		  manufacturer's installation instructions shall include tensioning adjustments
		  which may be needed to prevent damage to the manufactured home, particularly
		  damage that can be caused by frost heave.
(2) Each ground anchor shall have the
		  manufacturer's identification and listed model identification number marked
		  thereon so that the number is visible after installation. Instructions shall
		  accompany each listed ground anchor specifying the types of soil for which the
		  anchor is suitable under the requirements of paragraph (B) (3) (b) (4)
		  (a).
(3) Ground anchors, including
		  means for attaching ties, shall be located to effectively match the anchoring
		  system instructions provided by the manufactured home manufacturer, or, if
		  there are no instructions, in accordance with the requirements of this
		  section.
(4) If concrete slabs or
		  continuous footings are used to transfer the anchoring loads to the ground, the
		  following shall be required:
(a) Steel rods
		  cast in concrete shall be capable of resisting loads as specified in paragraph
		  (B) (3) (b) (4)(a).
(b) Deadman
		  concrete anchors may be used in place of listed anchors if they meet the
		  requirements of paragraph (B) (3) (b) (4) (a).
(c) Concrete slabs may be used in place of
		  ground anchors, provided the slab is constructed so that it provides holding
		  strength equal to the requirements of paragraph (B) (3) (b) (4)(a).
b. Foundation
		  Standards.
(1) Support System Spacing. Unless
		  a professional engineer or architect designs the entire support system, the
		  support system shall be designed in accordance with this standard.
(2) Footings. Footings shall be sized to
		  support the loads shown in the manufacturer's instructions and as specified
		  below. Where no manufacturer's instructions are available, the footings shall
		  be adequate in size to withstand the uniform live and dead loads of the
		  manufactured home and any concentrated loads.
(a) The supports shall begin not more than
		  two feet from the exterior of each end wall. Supports shall be installed
		  directly under the main frame (chassis) of the manufactured home.
(b) Table 2 in Appendix A shall be applicable
		  unless the entire support system is designed and calculated by a registered
		  professional engineer or architect.
(c) Footings shall be at least 144 square
		  inches of solid concrete, block, or other materials approved for the intended
		  use by the South Carolina Manufactured Housing Board. (Check Appendix B for
		  minimum thickness.)
(d) Footings or
		  pier foundations (unless approved by a registered professional engineer), when
		  required, shall be placed level on firm undisturbed soil or on controlled fill
		  which is free of grass and organic materials to minimum load-bearing capacity
		  of 1000 pounds per square foot. Where unusual conditions exist, the spacing of
		  piers and the load-bearing capacity of the soil shall be determined
		  specifically for such conditions (see paragraph (B) (6) (b)).
(3) Piers. Piers or load-bearing
		  supports or devices shall be designed and constructed to evenly distribute the
		  loads. Load-bearing supports or devices shall be listed and labeled, shall be
		  designed by a registered professional engineer or architect, shall be approved
		  for the use intended, or piers shall be constructed as follows:
(a) Piers less than 36 inches in height shall
		  be constructed of open or closed cell, eight inches by 16 inches, concrete
		  blocks (with open cells vertically placed upon the footing). Single-stacked
		  block piers shall be installed with the 16 inches perpendicular to the main
		  (Ibeam) frame. The piers shall be covered with a two inches by eight inches by
		  16 inches wood or concrete cap (See Figure B-10, Appendix B).
(b) Subject to the limitations of paragraph
		  (B) (4) (b), piers between 36 inches and 80 inches in height and all corner
		  piers over three blocks high shall be double blocked with blocks interlocked
		  and capped with a four inches by 16 inches by 16 inches solid concrete block,
		  or equivalent (See Figure B-11, Appendix B).
(c) Subject to the limitations of paragraph
		  (B) (4) (b), piers over 80 inches in height shall be constructed as per
		  paragraph (B) (3) (b) (3) and they shall be laid in concrete mortar and steel
		  reinforcing bars inserted in block cells with the block cells filled with
		  concrete (See Figures B-12 (a) and B-12 (b) in Appendix B).
(d) Steel Piers. Steel piers, when used,
		  shall be in compliance with paragraph (B) (3) (b) (5)(l), after fabrication to
		  provide corrosion protection (See B-8 in Appendix B).
(e) Walls. Load bearing and nonload-bearing
		  walls constructed on site shall be constructed of concrete, masonry, or any
		  other material or system that is recognized by the authority having
		  jurisdiction. Minimum thickness shall be that required to resist lateral
		  pressure from adjacent earth and support design loads as determined by
		  acceptable engineering practice.
(4) Anchors.
(a) Capacity of Anchors. Each approved ground
		  anchor, when installed, shall be capable of resisting an allowable working load
		  at least equal to 3,150 pounds in the direction of the tie plus a 50 percent
		  overload (4,725 pounds) without failure.
(b) Anchoring Equipment. Anchoring equipment,
		  shall be capable of resisting an allowable working load equal to or exceeding
		  3,150 pounds and shall be capable of withstanding a 50 percent overload (4,725
		  pounds) without failure of either the anchoring equipment or the attachment
		  point on the manufactured home. When the stabilizing system is designed by a
		  qualified registered professional engineer or architect, alternative working
		  loads may be used provided the anchoring equipment is capable of withstanding a
		  50 percent overload. All anchoring equipment shall be listed or labeled as
		  being capable of meeting all the requirements of this section.
(c) Anchor Installation Specifications. Each
		  type anchor suitable for this purpose shall have specification data showing the
		  soil classification(s) for which it qualifies.
(d) Anchors designed for connection of
		  multiple ties shall be capable of resisting the combined working load and
		  overload consistent with the intent expressed herein, and shall be installed to
		  resist resultant forces.
(e)
		  Selection of Anchors. Anchor selection shall be based on a determination of the
		  soil class at the depth the anchor helical plate will be installed.
(f) Other Anchoring Devices. Other anchoring
		  devices meeting the requirements of this section shall be permitted if
		  acceptable to the authority having jurisdiction.
(g) Depth of Anchors. All anchors shall be
		  installed to the full depth shown in the anchor manufacturer's installation
		  instructions. The load-carrying portion of the ground anchors shall extend
		  below the frost line.
(5) Ties. Strappings or other approved
		  methods or material shall be used for ties. All ties shall be fastened to
		  ground anchors and drawn tight with turnbuckles or other adjustable tensioning
		  devices or devices supplied with the ground anchor.
(a) Tie materials shall be capable of
		  resisting an allowable working load of 3,150 pounds with no more than two
		  percent elongation and shall withstand a 50 percent overload (4,725 pounds
		  total). Ties shall comply with the weathering requirements of paragraph (B) (3)
		  (b) (v) l).
(b) Ties shall connect
		  the ground anchor and the main structural steel frame (I-beam or other shape)
		  which runs lengthwise under the manufactured home. Ties shall not connect to
		  steel outrigger beams which fasten to and intersect the main structural frame
		  unless specifically stated in the manufacturer's installation
		  instructions.
(c) Connection of the
		  cable frame tie to the manufactured home I-beam or equivalent main structural
		  frame member shall be by a five-eighths inch drop-forged closed-eye bolt
		  through a hole drilled in the center of the I-beam web or other approved
		  methods. The web shall be reinforced if necessary to maintain the designed
		  I-beam strength.
(d) Cable ends
		  shall be secured with at least three U bolt-type cable clamps with the U
		  portion of the clamp installed on the short (dead) end of the cable to assure
		  strength equal to that required by paragraph (B) (3) (b) (v) a).
(e) Number of Ties. The minimum number of
		  ties per side for various lengths of manufactured homes in hurricane zone shall
		  be in accordance with Table 3 in Appendix A.
(f) Location of Ties. When continuous straps
		  are provided as vertical ties, such ties shall be positioned at rafters and
		  studs. Where a vertical tie and diagonal tie are located at the same place,
		  both ties shall be permitted to be connected to a single ground anchor,
		  provided that either the anchor used is capable of carrying both loadings, or
		  that the load capacity of the total number of anchors used is equal to 3150
		  pounds. Working load plus 50 percent overload (4725 pounds.) times the number
		  of ties specified in Table 3 in Appendix A.
(g) Spacing of Vertical Ties. Vertical ties
		  shall be as evenly spaced as practicable over rafters or over studs along the
		  length of the manufactured home with not more than eight feet open-end spacing
		  on each end.
(h) Special Ties.
		  Clerestory roofs and add-on sections of expandable manufactured homes shall
		  have provisions for vertical ties at the exposed ends.
(i) Alternate Method Using Strapping. If the
		  alternate method incorporating straps specified in Table 3 in Appendix A is
		  used, the baling straps shall be wrapped completely around the manufactured
		  home passing under the main steel frame, with both ends of each strap fastened
		  together under tension. The straps shall be in accordance with paragraph (B)
		  (3) (b) (v). The method used to connect the ends of the strap shall not reduce
		  the allowable working load and overload. S traps shall be installed in
		  accordance with the requirements for ties in paragraph (B) (3) (b) (v) a)
		  through l).
(j) Tensioning Device
		  Design. Tensioning devices such as turnbuckles or yoke-type fasteners shall be
		  ended with a clevis or forged or welded eyes.
(k) Permanency of Connections. Anchoring
		  equipment shall be designed to prevent self-disconnection when ties are slack.
		  Open hook ends shall not be used in any part of the anchoring system.
(l) Resistance to Weather Deterioration. All
		  anchoring equipment exposed to weathering shall have a resistance to weather
		  deterioration at least equivalent to that provided by a coating of zinc on
		  steel of not less than 0.30 ounces per square foot on each side of the surface
		  coated, as determined by ASTM Standard Methods of Test for Weight of Coating on
		  ZincCoated (Galvanized) Iron or Steel Articles (ASTM A90-B1).
4. Placement
		  of Manufactured Homes.
a. Clearance Under
		  Homes. A minimum clearance of 12 inches shall be maintained beneath the lowest
		  member of the main frame (I-beam or channel beam) in the area of utility
		  connections. No more than 25 percent of the underside of the main frame of the
		  home shall be less than 12 inches above grade.
b. Plates and Shims. A wood plate not
		  exceeding two inches in thickness and shims that transfer loads uniformly not
		  exceeding one inch in thickness shall be permitted to be used to fill any gap
		  between the top of the pier and the main frame. Two, two inches or four inches
		  solid concrete blocks shall be permitted to be used to fill the remainder of
		  any gap. Shims shall be at least nominal four inches wide and six inches long
		  and shall be fitted and driven tight between the wood plate or pier and main
		  frame.
c. Elevated Manufactured
		  Homes. When the manufactured home is installed on a basement or split entry
		  type foundation over a habitable lower-level area, or when more than one-fourth
		  of the area of a manufactured home is installed so that the bottom of the main
		  frame members are more than three feet above ground level, the foundation
		  system shall be designed by a registered professional engineer or architect and
		  the installation shall be approved by the local authority having
		  jurisdiction.
d. Removal of
		  Manufactured Home Transportation Components at Time of Installation. No portion
		  of a manufactured home shall be removed when located on its home site unless it
		  is designated to be removable and removed in accordance with the manufacturer's
		  instructions.
5.
		  Ventilation of Manufactured Homes.
a. Access
		  to and Ventilation of Underfloor Areas.
(1)
		  Provisions shall be made to minimize condensation in underfloor areas through
		  ventilation openings or other suitable means.
(2) If combustion air for heat-producing
		  appliance(s) is taken from within the underfloor areas, ventilation shall be
		  adequate to assure proper operation of the appliance(s). This requirement shall
		  take precedence over the provisions of paragraph (B) (5) (a) (i).
(3) Ventilation openings shall be provided
		  for low profiled manufactured homes that are installed by depressing the
		  supporting foundation in accordance with paragraph (B) (5) (a) (iv).
(4) A minimum of four ventilation openings
		  shall be provided from the underfloor space to the exterior. One shall be
		  placed at or near each corner as high as practicable. Their total net area
		  shall be calculated by: a = A/150 where: A = the area of the crawl space,
		  square feet a = the total net free vent area.
(a) Openings shall provide cross ventilation
		  on at least two opposite sides. The openings shall be covered with corrosion
		  resistant wire mesh not less than one-eighth inch and not more than one-half
		  inch in any dimension or with screened louvered openings to retard entry of dry
		  vegetation, waste materials, or rodents.
(b) Intake air for ventilation purposes shall
		  not be drawn from underfloor spaces of the home.
(c) Moisture producing devices, such as
		  dryers, shall be vented to the atmosphere in such a manner to insure that
		  moisture laden air is carried beyond the perimeter of the home.
(d) Curtain Walls. Curtain walls, if used,
		  although not necessary for stabilizing the home, shall be installed in
		  accordance with the manufacturer's installation instructions. It shall be
		  secured, as necessary, to assure stability, to minimize vibrations, to minimize
		  susceptibility to wind damage, and to compensate for possible frost heave.
		  Access opening(s) not less than 18 inches in any dimension and not less than
		  three square feet in area shall be provided and shall be located so that any
		  water supply and sewer drain connections located under the manufactured home
		  are accessible for inspection. Such access panel(s) or door(s) shall not be
		  fastened in a manner requiring the use of a special tool to remove or open
		  same. On-site fabrication of curtain wall shall meet the objectives cited
		  herein. Materials designed for curtain walls may be used, including, but not
		  limited to vinyl, treated wood, corrosion resistant metal or masonry products.
		  Curtain walls constructed or installed in accordance with this provision
		  satisfy the requirements of the Act.
(5) Maintenance.
(a) Protection of Ties and Manufactured Home
		  Roofing and Siding. Protection shall be provided at sharp corners where the
		  anchoring system requires the use of external cables or straps. Protection
		  shall also be provided to minimize damage to roofing or siding by the cable or
		  strap.
(b) Maintenance of Anchoring
		  Systems. The homeowner shall be advised that tie tension should be checked and
		  adjusted when necessary to prevent damage to the manufactured home from
		  settling or other unforeseen movements (such as frost heave).