{
  "title": "Mobile Home Pier Spacing Chart: Federal Calculated Spacing and Texas Pier Spacing Capacity Crosswalk",
  "publisher": "Corpus Christi Mobile Home Leveling Research",
  "canonical_url": "https://corpuschristimobilehomeleveling.com/research/mobile-home-pier-spacing-chart/",
  "dataset_version": "2026.07.28.1",
  "date_published": "2026-07-28",
  "date_verified": "2026-07-28",
  "description": "Two reproducible derivative datasets built from current federal and Texas primary-source tables: 204 federal rows and 380 Texas rows.",
  "verification_marks": {
    "★": "Read directly against the cited primary regulation or official table.",
    "●": "Calculated deterministically from two or more ★ source values; reproducible, but not itself regulatory text."
  },
  "federal_method": {
    "source_inputs": [
      "24 CFR 3285.303 Table 1 or Table 2 required frame-pier loads",
      "24 CFR 3285.312 footing table, 8x16 pier column, including minimum unreinforced cast-in-place thickness",
      "24 CFR 3285.312 Note 4 single-stack 8x16 block-pier cap of 8,000 lb",
      "24 CFR 3285.310(c) outer spacing cap of 120 inches"
    ],
    "calculation": "For each soil, footing and roof-live-load row, governing capacity is the lesser of published footing capacity and 8,000 lb. The dataset then solves for the largest spacing whose required frame-pier load does not exceed governing capacity. Linear interpolation is used only between published 4, 6, 8 and 10 ft rows, as permitted by the applicable table note.",
    "display_rule": "Exact decimal feet and inches are retained. The human-readable display is floored to the lower whole inch so a published maximum is never rounded upward.",
    "precast_note": "Under Note 2 to the 24 CFR 3285.312 table, only values with a 6 in cast-in-place minimum thickness may be used for 4 in unreinforced precast concrete footings."
  },
  "texas_method": {
    "source_inputs": [
      "10 TAC 80.23 footer capacities",
      "10 TAC 80.23 pier-load tables by width, support configuration and spacing",
      "10 TAC 80.23 beam-depth spacing limits"
    ],
    "calculation": "Select the largest listed spacing whose required pier load is less than or equal to the listed footing capacity. No interpolation. Main I-beam results with perimeter support are also capped at 8, 10 or 12 ft for 8, 10 or 12 in beams.",
    "applicability": "The crosswalk is derived from the Texas generic standards option for used homes under 10 TAC 80.21(b)(2). New Texas homes use the manufacturer DAPIA-approved instructions."
  },
  "limitations": [
    "The datasets are reference calculations, not a site-specific foundation design.",
    "The 10 ft federal value is an outer cap and does not establish a universal permitted spacing.",
    "Federal Table 1 and Table 2 carry stated home-width, beam, dead-load and eave assumptions; Table 3 has its own stated assumptions.",
    "The federal tables exclude flood and seismic loads.",
    "Footing capacities are material- and thickness-specific; the 24 CFR 3285.312 table is for unreinforced cast-in-place footings, with a limited 4 in precast allowance in Note 2.",
    "The Texas crosswalk applies only where the Texas generic used-home method controls.",
    "Pier spacing and anchor or tie-down spacing are different variables."
  ],
  "sources": [
    {
      "title": "24 CFR 3285.202",
      "url": "https://www.ecfr.gov/current/title-24/subtitle-B/chapter-XX/part-3285/subpart-C/section-3285.202",
      "checked": "2026-07-28"
    },
    {
      "title": "24 CFR 3285.303",
      "url": "https://www.ecfr.gov/current/title-24/subtitle-B/chapter-XX/part-3285/subpart-D/section-3285.303",
      "checked": "2026-07-28"
    },
    {
      "title": "24 CFR 3285.310",
      "url": "https://www.ecfr.gov/current/title-24/subtitle-B/chapter-XX/part-3285/subpart-D/section-3285.310",
      "checked": "2026-07-28"
    },
    {
      "title": "24 CFR 3285.312",
      "url": "https://www.ecfr.gov/current/title-24/subtitle-B/chapter-XX/part-3285/subpart-D/section-3285.312",
      "checked": "2026-07-28"
    },
    {
      "title": "HUD Manufactured Home Installation Program FAQ",
      "url": "https://www.hud.gov/hud-partners/manufactured-home",
      "checked": "2026-07-28"
    },
    {
      "title": "TDHCA Manufactured Housing Rules effective 2025-12-21",
      "url": "https://www.tdhca.texas.gov/sites/default/files/mh/docs/251221-MH-HousingRules_0.pdf",
      "checked": "2026-07-28"
    },
    {
      "title": "Mississippi Regulation MH-5 effective 2026-07-01",
      "url": "https://www.mid.ms.gov/wp-content/uploads/2026/06/MH-5reg.pdf",
      "checked": "2026-07-28"
    }
  ],
  "distributions": [
    {
      "file": "federal-max-pier-spacing-frame-only.csv",
      "format": "text/csv",
      "rows": 102,
      "description": "Federal frame-only calculated maximum spacing by soil, footing and roof live load."
    },
    {
      "file": "federal-max-pier-spacing-frame-plus-perimeter.csv",
      "format": "text/csv",
      "rows": 102,
      "description": "Federal frame-pier calculated maximum spacing when perimeter blocking carries separate roof loads."
    },
    {
      "file": "texas-pier-spacing-crosswalk.csv",
      "format": "text/csv",
      "rows": 380,
      "description": "Texas used-home generic-standard crosswalk by support configuration, width, beam depth, footing and soil."
    }
  ],
  "quality_checks": {
    "federal_rows_per_blocking_case": 102,
    "federal_soil_footing_combinations": 34,
    "federal_combinations_capped_by_single_stack_pier": 19,
    "texas_rows": 380,
    "texas_no_supported_tabulated_spacing_rows": 3,
    "texas_worked_examples_reproduced": 2
  }
}