Section 80.24 - Generic Standards for Anchoring Systems(a) General Requirements: For units built on or after September 1, 1997, the installer must verify that the unit is designed for the Wind Zone in which it is to be installed and must follow all applicable installation instructions for that Wind Zone as set forth herein. Note: A Wind Zone I unit, built on or after September 1, 1997, may not be installed in a Wind Zone II area. However, a Wind Zone II unit may be installed in a Wind Zone I area. The counties are defined in the FMHCSS.(b) Material Specifications: (1) Strapping shall be Type 1, Finish B, Grade 1 steel strapping, 1.25 inches wide and 0.035 inches in thickness, certified by a licensed professional engineer or architect as conforming with the American Society for Testing and Materials (ASTM) Standard Specification D3953 91, Standard Specification for Strapping, Flat Steel, and Seals. Strapping shall be marked at least every five feet with the marking described by the certifying engineer or architect.(2) Tie materials shall be capable of resisting an allowable working load of 3,150 pounds with no more than 2% elongation and shall withstand a 50% overload (4,725 pounds total). Ties shall have a resistance to weather deterioration at least equivalent to that provided by coating of zinc on steel of not less than 0.30 ounces per square foot on each side of the surface coated (0.0005 inches thick), as determined by ASTM Standards Methods of Test for Weight of Coating on Zinc-coated (galvanized) Iron or Steel Articles (ASTM A 90-81). Slit or cut edges of zinc-coated steel strapping are not required to be zinc coated. Ties shall be designed and installed to prevent self disconnection when the ties are slack.(3) Anchor spacing ONLY applies to units with roof pitch of 20 degrees or less. For anything over 20 degrees, it must be designed by a professional engineer or architect.(c) Anchors shall be installed: (2) against direction of load (vertical and/or angled), and a stabilizer plate must be installed. See the following Placement of Stabilizing Devices. Attached Graphic
(d) WIND ZONE I Installation: (1) Typical anchor layout, single and multi-section units (WIND ZONE I ONLY). Attached Graphic
(3) Minimum Number of Diagonal Ties for Wind Zone I. Table based on 2 feet inset of anchors at each end. Attached Graphic
(4) When auger anchors cannot be inserted into a difficult soil after moistening, such as mixed soil and rock or caliche (heavily weathered limestone) that is not solid rock, cross drive rock anchors may be used in accordance with the values and notes for the table modified as follows: (A) Since the ultimate anchor pull out in the difficult soil will be reduced, the maximum spacing for diagonal ties per side is one half the spacing allowed by the table in paragraph (2) of this subsection which will require adding one additional cross drive rock anchor for each anchor specified for the sides and ends;(B) The rods of the cross drive rock anchors must be fully inserted, have at least 24 inches of the rod lengths embedded in the difficult soil, and be restrained from horizontal movement by a stabilizer device between the rods and the home; and(C) Each cross drive rock anchor is connected to one diagonal tie and is not connected to a vertical tie.(5) Where vertical tie locations are not easily discernable, the vertical ties may be connected to the main I-Beam rails and the anchor installed directly below that connection point. The diagonal tie must be connected to the opposite main I-Beam. In no case shall the distance between those ties exceed 5'-4" on-center.(e) WIND ZONE II Installation: (1) In place of the requirements as shown in subsection (d) of this section, units designed for Wind Zone I and built prior to September 1, 1997, and units designed for Wind Zone II and built prior to July 13, 1994, require diagonal ties as set forth in this paragraph when these units are installed in Wind Zone II. See also §1201.256 of the Standards Act. Items not specifically addressed in this section are the same as for Wind Zone I installations. Attached Graphic
(2) Units built to Wind Zone II on or after July 13, 1994. (A) Units built to Wind Zone II on or after July 13, 1994, should have either built-in, or provisions for connecting, vertical ties along the sidewall(s) of each unit(s). A diagonal tie must be installed at each vertical tie location (except for designated shearwall tie). Built-in vertical ties shall be connected to anchors. If there are brackets or other provisions for connecting vertical ties, vertical ties shall be added at the brackets or provisions and connected to anchors.(B) Only factory installed vertical ties may be closer than 4 feet from each other.(C) Where tie locations are clearly marked as a shear wall strap, a perimeter pier must be installed at that location. Diagonal tie is not required.(D) Where the vertical tie spacing exceeds 8'-0" on-center (see also note 6 in the table in this paragraph for exception), the anchoring system must be approved by the home manufacturer's installation manual, or designed by a professional engineer or architect licensed in the state of Texas.(E) Where pier heights exceed 36 inches in height, the diagonal strap shall be connected to the opposite I-Beam.(3) Multi-section centerline anchoring requirements (Wind Zone II only): (A) Centerline anchor ties are required for ALL Wind Zone II installations, regardless of the date the unit was manufactured, when installation occurs on or after the effective date of these rules.(B) Factory installed centerline vertical ties, brackets, buckles or any other connecting devices must be connected to a ground anchor. No additional anchors as described in subparagraph (D) of this paragraph are required.(C) To avoid obstructions and/or piers and footers, the anchor may be offset up to 12 inches perpendicular to the centerline.(D) Where factory preparations do not exist, install anchors and angle iron brackets at each side of mating line openings wider than 48 inches. (i) Where equal spans exist opposite each other (i.e., each section), a double bracket assembly may be used. The maximum opening is per the table in subsection (f)(4) of this section. Total uplift load may not exceed the anchor and/or strap capacity (i.e., 3150 pounds).(ii) The angle iron bracket is minimum 1 1/2" x 1 1/2" x 11 gauge. The holes for the lag screws are a maximum of 4 inches apart and 3/4" from the edge of the bracket.(iii) Lag screws/bolts are minimum 3/8? diameter x 3 inches, full thread. Note: Pre drill pilot holes.(4) For openings separated by a wall or post 16 inches or less in width, the opening span is the total of the spans on each side of the wall/post.(f) Bracket Installation. (1) See the table in paragraph (4) of this subsection concerning the maximum centerline wall opening for column uplift brackets.(2) Use a single bracket for openings which exist on one section only. Use double bracket where openings are opposite each other on two sections of the home.(3) When only one bracket assembly is required, it may be installed on either side of the column/opening stud(s), but no more than 12 inches from the column or opening stud(s).(4) When two bracket assemblies are required, they must be installed on each side of the column/opening stud(s), but no more than 12 inches from the column/opening stud(s), and they must be angled away from each other a minimum of 12 inches. Attached Graphic
(5) Example: A double section unit with each section being 14 feet wide; (A) Span "A" is 18'-0", matching span both sections;(B) Span "B" is 14'-8", matching span both sections;(C) Span "C" is 6'-8", matching span both sections; and(6) Longitudinal ties: (A) Longitudinal ties are required for ALL wind zone installations, regardless of the date of manufacture, when installation occurs after the effective date of these rules.(B) Longitudinal ties are designed to prevent lateral movement along the length of the home.(C) When conventional anchors and straps are used; the required number of ties must be installed as appropriate. The strap(s) may be connected or wrapped around front or rear chassis header members, around existing cross members or spring hangers. A strap must be within 3 inches of where the cross member attaches to the main I-beam. Alternatively, brackets to receive the strap(s) may be attached to the bottom flange of the main I-beams. The location of the connection points along the length of the I-beams are not critical, as long as the number of longitudinal ties required for each end of each home section are installed with their pull in opposite directions. No two anchors shall be within 4 ft of each other. No two ties shall be attached to the same structural member of the home, other than a main longitudinal frame member or a front or rear chassis header member.(D) Anchors require stabilizer plates when the anchor shaft is not in line with strap (plus or minus 10 degrees).10 Tex. Admin. Code § 80.24
The provisions of this §80.24 adopted to be effective January 29, 2008, 32 TexReg 8790