Mobile Home Pier Spacing Chart

Last verified: July 28, 2026Primary sources only · 19 citations

Key Statistics

1. Federal frame-pier outer limit: 120 inches (10 feet) on center under the main rails; no more than 24 inches from both ends. (§3285.310(c))
2. 8,500 lb vs. 8,000 lb: At 40 psf, Table 1 requires 8,500 lb at 10 ft — exceeding the 8,000 lb single-stack pier cap. The pier cap is binding at that row.
3. 9′–4″ (112.5 in): The exact calculated frame-only maximum at 8,000 lb governing capacity, 40 psf — interpolated between the 8-ft and 10-ft Table 1 rows and floored to the lower whole inch.
4. 19 of 34: Federal soil-and-footing combinations where the 8,000 lb single-stack pier cap governs over the published footing capacity.
5. 61–66% frame-load reduction: At 40 psf with separate perimeter blocking, the frame-pier required load drops from 8,500 lb (frame only) to 2,900 lb — a 66% reduction at 10-ft spacing.
6. Federal scope: 24 CFR Part 3285 covers the initial installation of new manufactured homes. It does not itself create a used-home or releveling standard.
7. Minimum CIP thickness: The §3285.312 table states the minimum unreinforced cast-in-place concrete footing thickness for each soil-and-footing size, ranging from 6 to 18 inches in the 8×16 pier column.
8. Texas beam-depth caps: With perimeter support, Texas limits main I-beam spacing to 8 ft (8-in beam), 10 ft (10-in beam), or 12 ft (12-in beam) — subject to the shorter result from the footer capacity calculation.
9. Texas no-perimeter stop: The Texas generic no-perimeter table stops at 8 ft for 12-, 14-, and 16-ft-wide sections and excludes 18-ft-wide sections from the no-perimeter option.
10. Texas 30% redistribution: Texas permits listed spacing to be exceeded by up to 30% only when the total pier count remains unchanged — a redistribution provision, not permission to remove piers.
11. MH/CH soil values: The federal standard assigns 1,000 psf to MH and CH soils; Texas assigns 1,500 psf to the same ASTM symbols — a 50% difference in the same soil class.
12. Federal default soil: Federal rules use 1,500 psf as the unknown-soil default unless site information indicates lower; Texas has no equivalent default and requires exact soil determination.
13. Single-stack height limits: Federal single-stack 8×16 block pier: less than 36 inches. Texas Pier A detail: 36-inch limit. Federal double-stack: 36–67 inches.
14. Texas 4-ft worked example: A 16-ft-wide section on a 16×16×4 footer at 1,500 psf soil yields 4 ft — the footer capacity (2,700 lb) is exceeded by the 5-ft required load (2,900 lb).
15. 1,000 psf footing results: At 1,000 psf soil, no supported spacing exists for 16×16 or 20×20 footings in the federal frame-only chart; a 24×24 footing yields a minimum result starting at 4 ft for 20 psf load.

This is a reference chart, not a foundation design.The correct spacing for a particular home on a particular property depends on the controlling installation instructions, site conditions, and a qualified assessment. Nothing on this page substitutes for the manufacturer’s DAPIA-approved instructions, a registered system’s requirements, or a site-specific design by a licensed engineer or architect.

This chart joins the federal model installation standard’s pier-load tables with the footing-capacity table and the single-stack block-pier cap, then builds a 380-row Texas crosswalk from official state rules effective December 21, 2025. Every figure is cited to a primary government source. The page does not publish a national average, a universal pier count, or a default spacing — verified provisions show why those figures cannot be produced from the official tables.

For context on mobile home leveling in Corpus Christi, see the homepage. For pier and support repair information, see the service page. The resources section includes preparation tools for homeowners. For cost data, see the 2026 published price audit.

1. Controlling Standard — Which Rule Applies

Before any spacing number means anything, the governing document has to be identified. The federal model standard, the manufacturer’s approved instructions, a state’s used-home rules, a registered stabilization system and a site-specific engineered design are different authorities, and they do not all apply to the same home or the same work.

24 CFR Part 3285 expressly covers the initial installation of new manufactured homes. It does not itself establish the rule for every used, relocated or already-installed home. A bare citation to the federal 10-foot figure therefore cannot establish the spacing for a used home being installed or releveled under a state program.

Table: Controlling Standard by Situation
Situation	Starting authority	What this page can establish
New manufactured home	Manufacturer’s DAPIA-approved installation instructions	Federal context and source-table meaning, not a substitute spacing
Used home in Texas using the generic-standards option	10 TAC §§80.21–80.25	The Texas source tables and calculated crosswalk below
Home using a registered stabilization or foundation system	The registered system’s instructions	General context only
Flood or seismic hazard, unusual soil, or a pier over 67 in	Applicable approved or site-specific design by a registered professional engineer or architect	Why the generic federal tables can be excluded or insufficient
Used or relocated home outside Texas	Applicable state and local law, controlling manufacturer instructions, registered system or engineered design	This page does not substitute a 50-state applicability determination

Source: 24 CFR §§3285.1, 3285.2, 3285.301–3285.302 and 3285.306; 10 TAC §80.21. Verified July 28, 2026.

How does the federal model standard relate to state installation programs?

Under 24 CFR §3285.1(a)(1)–(2), a qualifying state installation program must provide protection that equals or exceeds the protection in the federal model standards. In a state without a qualifying program, the federal model standards establish the minimum requirements for the initial installation of new manufactured homes. That relationship does not turn Part 3285 into a universal releveling or used-home rule.

DAPIA stands for Design Approval Primary Inspection Agency. Under 24 CFR §3285.2, each new manufactured home must be provided with manufacturer installation instructions approved by the Secretary or DAPIA, and those instructions must meet or exceed the protection provided by the model standards.

Texas new/used distinction:Under 10 TAC §80.21(a), a new home must be installed by a licensed installer according to the manufacturer’s DAPIA-approved instructions. Under §80.21(b), a used home may be installed under one of four permitted methods: the manufacturer’s instructions, the Texas generic standards, a stabilization system registered with the department, or a specially designed system stamped by a Texas-licensed engineer or architect. The Texas crosswalk on this page derives only from the generic-standards option.

2. The Federal 10-Foot Maximum

The federal model standard states two geometric outer limits: frame piers no more than 120 inches, or 10 feet, on center under the main rails, and frame piers no more than 24 inches from both ends of the home. Section 3285.310 lists the design variables that control the actual support layout before stating those limits. Those variables include the home’s dimensions, live and dead loads, single- or multi-section construction, I-beam size, soil bearing capacity, footing size and the locations of doors and other openings. The 120-inch figure is therefore the outside boundary of a conditional calculation, not a default spacing.

Terms used.On center (o.c.) means measured from the center of one pier to the center of the next. The main rails or main I-beams are the long steel beams forming the home’s chassis. Roof live load is the design load a roof must carry beyond its own dead weight, expressed in pounds per square foot (psf). Soil bearing capacity is the allowable pressure the ground can support per square foot.

Three limits stack to produce the actual allowed spacing: the footing ceiling (load the footing can transfer to soil), the pier ceiling (8,000 lb single-stack / 16,000 lb double-stack), and the geometric ceiling (120 in). The regulation publishes those inputs separately. The next section joins them under one stated set of assumptions.

Table: Federal Geometric Limits for Frame Pier Placement
Rule	Federal value	Qualification	Citation
Maximum frame-pier spacing	120 in (10 ft) o.c.	Under the main rails; an outer limit	§3285.310(c)
Maximum end-pier distance	24 in from both ends	Measured to the pier center as shown in the federal figures	§3285.310(c); Figures A and B notes
Permitted pier offset	Up to 6 in in either direction	To clear plumbing, electrical, mechanical or crawlspace obstructions	Notes to Figures A and B in §3285.310
Unsupported open span	Intermediate supports at no more than 10 ft o.c.	Where an open span exceeds 10 ft	Figure B note in §3285.310
Mating-wall openings	No pier under 48 in; supports on both sides at 48 in or more	At 40 psf or above, a PE or RA determines the maximum unsupported opening	§3285.310 figures; §3285.311(a)(1)
Minimum clearance under home	12 in from the lowest main-frame member to grade	Federal site-clearance requirement	§3285.305

Source: 24 CFR §§3285.305, 3285.310 and 3285.311, current eCFR verified July 28, 2026.

3. Derived Federal Chart: Frame-Only Spacings

This calculated chart joins the federal required frame-pier loads with the federal footing-capacity table and the single-stack block-pier limit. The results range from no supported value at the smallest four-foot Table 1 row to the full 10-foot geometric cap, which is why one number cannot answer every federal-table case.

The calculation uses the 8×16 pier column of the §3285.312 table for an unreinforced cast-in-place concrete footing. For each row, governing capacity is the lesser of the published footing capacity and 8,000 lb. The calculation then finds the largest spacing supported by Table 1, uses linear interpolation where the table permits it and caps the result at 10 feet. Exact decimals remain in the CSV; visible maximums are floored to the lower whole inch so they are never rounded upward.

Key: ★ = source-table value | ● = calculated value | † = precast concrete footing may be used at this thickness per Note 3 to §3285.312 Table

Table: Derived Federal Frame-Only Maximum Pier Spacing — Single-Stack 8×16 Block Pier, Unreinforced CIP Footing (34 rows)
Soil (psf)	Footing (in)	Min. CIP thickness (in)	Footing capacity (lb)	Governing capacity (lb)	20 psf	30 psf	40 psf	Binding limit
1,000	16×16	6†	1,600	1,600	—	—	—	footing/soil
1,000	20×20	6†	2,600	2,600	—	—	—	footing/soil
1,000	24×24	6†	3,700	3,700	5′–2″	4′–6″	4′–1″	footing/soil
1,000	30×30	8	5,600	5,600	8′–1″	7′–2″	6′–5″	footing/soil
1,000	36×36	10	7,900	7,900	10′–0″	10′–0″	9′–3″	footing/soil
1,000	42×42	10	10,700	8,000	10′–0″	10′–0″	9′–4″	block pier cap
1,000	48×48	12	13,100	8,000	10′–0″	10′–0″	9′–4″	block pier cap
1,500	16×16	6†	2,500	2,500	—	—	—	footing/soil
1,500	20×20	6†	4,000	4,000	5′–8″	5′–0″	4′–6″	footing/soil
1,500	24×24	8	5,600	5,600	8′–1″	7′–2″	6′–5″	footing/soil
1,500	30×30	10	8,500	8,000	10′–0″	10′–0″	9′–4″	block pier cap
1,500	36×36	10	12,400	8,000	10′–0″	10′–0″	9′–4″	block pier cap
1,500	42×42	12	16,500	8,000	10′–0″	10′–0″	9′–4″	block pier cap
1,500	48×48	14	21,200	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,000	16×16	6†	3,400	3,400	4′–9″	4′–1″	—	footing/soil
2,000	20×20	6†	5,300	5,300	7′–8″	6′–9″	6′–1″	footing/soil
2,000	24×24	8	7,600	7,600	10′–0″	10′–0″	8′–10″	footing/soil
2,000	30×30	10	11,700	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,000	36×36	15	16,700	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,000	42×42	18	21,700	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,500	16×16	6†	4,300	4,300	6′–1″	5′–5″	4′–10″	footing/soil
2,500	20×20	6†	6,700	6,700	9′–10″	8′–8″	7′–9″	footing/soil
2,500	24×24	8	9,600	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,500	30×30	10	14,800	8,000	10′–0″	10′–0″	9′–4″	block pier cap
2,500	36×36	12	20,700	8,000	10′–0″	10′–0″	9′–4″	block pier cap
3,000	16×16	6†	5,200	5,200	7′–6″	6′–8″	6′–0″	footing/soil
3,000	20×20	8	8,100	8,000	10′–0″	10′–0″	9′–4″	block pier cap
3,000	24×24	10	11,500	8,000	10′–0″	10′–0″	9′–4″	block pier cap
3,000	30×30	12	17,800	8,000	10′–0″	10′–0″	9′–4″	block pier cap
3,000	36×36	14	25,400	8,000	10′–0″	10′–0″	9′–4″	block pier cap
4,000	16×16	6†	7,000	7,000	10′–0″	9′–1″	8′–1″	footing/soil
4,000	20×20	8	10,800	8,000	10′–0″	10′–0″	9′–4″	block pier cap
4,000	24×24	10	15,500	8,000	10′–0″	10′–0″	9′–4″	block pier cap
4,000	30×30	12	23,300	8,000	10′–0″	10′–0″	9′–4″	block pier cap

Source: ★ 24 CFR §§3285.303 (Tables 1 and 2) and 3285.312 (footing table), current eCFR and 2025 annual CFR edition verified July 28, 2026. ● Calculated values use linear interpolation between published rows; results floored to the lower whole inch.

The 40 psf result under an 8,000 lb governing capacity is exactly 9.375 feet, or 112.5 inches. The chart prints 9′–4″, not 9′–5″, because a calculated maximum must not be rounded upward. The CSV preserves both the exact value and the conservative whole-inch display.

Frame-Plus-Perimeter: Derived Maximum Frame-Pier Spacing

When separate perimeter and mating-wall supports are used, federal Table 2 reduces the required frame-pier load. This chart applies the same footing-and-pier-cap calculation to those reduced loads.

Table: Derived Federal Frame-Plus-Perimeter Maximum Frame-Pier Spacing (6 soil classes, all at 40 psf)
Soil (psf)	16×16 footing	20×20	24×24	30×30 and larger
1,000	4′–9″	8′–9″	10′–0″	10′–0″
1,500	8′–4″	10′–0″	10′–0″	10′–0″
2,000	10′–0″	10′–0″	10′–0″	10′–0″
2,500	10′–0″	10′–0″	10′–0″	10′–0″
3,000	10′–0″	10′–0″	10′–0″	10′–0″
4,000	10′–0″	10′–0″	10′–0″	10′–0″

Source: ★ 24 CFR §3285.303 Table 2 (frame-pier loads with separate perimeter blocking) and §3285.312 footing table, verified July 28, 2026.

Perimeter and mating-wall supports must be sized from their own Table 2 and Table 3 loads and are not sized by this frame-pier table.

Frame-Load Reduction with Separate Perimeter Blocking

Table: Required Frame-Pier Load — Frame Blocking Only vs. Frame Plus Perimeter Blocking (40 psf)
Spacing	Frame blocking only (lb)	Frame plus perimeter blocking (lb)	Frame-load reduction
4 ft o.c.	3,600	1,400	61%
6 ft o.c.	5,200	1,900	63%
8 ft o.c.	6,900	2,400	65%
10 ft o.c.	8,500	2,900	66%

Source: ★ 24 CFR §3285.303 Tables 1 and 2. Verified July 28, 2026.

4. The 8,000 lb Block-Pier Cap

In 19 of the 34 federal soil-and-footing combinations used in the single-stack calculation, the published footing capacity exceeds the 8,000 lb design-capacity limit for an 8×16 single-stack concrete-block pier. Past that point, a larger footing does not widen the calculated spacing unless the pier system and every other controlling condition also change.

The cap appears in Note 4 to the §3285.312 footing table. The note limits an 8×16 single-stack concrete-block pier to 8,000 lb and a 16×16 double-stack concrete-block pier to 16,000 lb.

Three consequences flow from this cap:

1. The 10-foot row has a capacity condition attached. At 40 psf, Table 1 requires 8,500 lb, so a single-stack system cannot reach the 10-foot row. The cap removes that row from the calculation regardless of footing size.
2. A much larger footing can add almost nothing after the cap takes over. At 1,000 psf soil, the 48×48 footing has 13,100 lb capacity but is reduced to 8,000 lb and yields 9′–4″ — seven more square feet of concrete yet adds only one inch over the 42×42 result.
3. Separate perimeter support changes where the roof load goes. At 40 psf, Table 2 reduces the required frame-pier load by 61% to 66% — a transfer to the perimeter system, not a disappearance of the load. The perimeter piers must still be sized for their own Table 2 loads.

5. Federal Source Tables (Tables 1, 2, 3)

The three tables below are the primary federal regulatory sources. They are reproduced directly from 24 CFR §3285.303 as verified in the current eCFR and the 2025 annual CFR edition on GovInfo.

Table 1 — Required Frame-Pier Loads (Frame Blocking Only)

Table 1 to 24 CFR §3285.303: Required frame-pier vertical loads (lb) — frame blocking only
Pier spacing	20 psf roof live load	30 psf	40 psf
4 ft 0 in	2,900	3,300	3,600
6 ft 0 in	4,200	4,700	5,200
8 ft 0 in	5,500	6,200	6,900
10 ft 0 in	6,800	7,600	8,500

Source: ★ Table 1 to 24 CFR §3285.303, current eCFR and 2025 annual CFR edition verified July 28, 2026.

Table 2 — Required Pier Loads with Separate Perimeter Blocking

Table 2 to 24 CFR §3285.303: Required vertical loads (lb) — frame, perimeter, and mating-wall supports with separate perimeter blocking
Spacing	Frame	Perimeter 20 psf	Perimeter 30 psf	Perimeter 40 psf	Mating 20 psf	Mating 30 psf	Mating 40 psf
4 ft	1,400	1,900	2,300	2,600	3,200	3,800	4,400
6 ft	1,900	2,700	3,200	3,700	4,700	5,600	6,500
8 ft	2,400	3,500	4,200	4,800	6,100	7,300	8,500
10 ft	2,900	4,300	5,100	6,000	7,600	9,100	10,600

Source: ★ Table 2 to 24 CFR §3285.303, verified July 28, 2026.

Table 3 — Mating-Wall Opening Loads

Table 3 to 24 CFR §3285.303: Required mating-wall opening support loads (lb per support)
Mating-wall opening	20 psf	30 psf	40 psf
5 ft	1,200	1,600	1,900
10 ft	2,300	3,100	3,800
15 ft	3,500	4,700	5,800
20 ft	4,700	6,200	7,500
25 ft	5,800	7,800	9,700
30 ft	7,000	9,300	11,600
35 ft	8,100	10,900	13,600

Source: ★ Table 3 to 24 CFR §3285.303, verified July 28, 2026.

Table 3 wording conflict:The current regulation contradicts itself about whether the Table 3 column loads apply to each section or both sections together. Table 3 Note 3 says “each section,” while Figure C Note 2 describes the same loads as totals for both sections. HUD’s current Manufactured Home Installation Program FAQ identifies Figure C Note 2 as correct. HUD also states that Table 3 Note 3 will be revised. The current CFR text still contains the conflicting phrase, so this page preserves the official values, follows HUD’s stated interpretation and discloses the discrepancy.

Federal Soil Classification Table

Table to 24 CFR §3285.202: Federal soil classification for manufactured home installation
Class	ASTM symbols	Description	Allowable pressure (psf)	Blow count	Torque probe (in-lb)
1	—	Rock or hard pan	4,000+	—	—
2	GW, GP, SW, SP, GM, SM	Sandy gravel and gravel; very dense or cemented sands; coarse gravel and cobbles; preloaded silts, clays and coral	2,000	40+	more than 550
3	GC, SC, ML, CL	Sand; silty sand; clayey sand; silty gravel; medium-dense coarse sands; sandy gravel; very stiff silt and sand clays	1,500	24–39	351–550
4A	CG, MH	Loose to medium-dense sands; firm to stiff clays and silts; alluvial fills	1,000	18–23	276–350
4B	CH, MH	Loose sands; firm clays; alluvial fills	1,000	12–17	175–275
5	OL, OH, PT	Uncompacted fill; peat; organic clays	See §3285.202(e)	0–11	less than 175

Source: ★ Table to 24 CFR §3285.202, verified July 28, 2026.

Note:The current eCFR soil table prints “CG, MH” in class 4A while Note 2 to the same table refers to CH and MH. This page preserves the printed symbol rather than silently correcting the federal text.

6. Federal vs. Texas: 12 Verified Differences

Texas’s generic used-home standards and the federal new-home model standard organize pier support differently. The verified comparison below documents twelve differences without treating either rule set as a universal substitute for the other.

Texas can be tighter in one row and publish a larger number in another. With perimeter support, its generic used-home table reaches 12 feet for a 12-inch I-beam when the soil-and-footing result supports it, while its no-perimeter table stops at 8 feet and excludes 18-foot-wide sections. The 50% soil-value difference is exact for MH and CH symbols. The 30% redistribution provision preserves total pier count — it is not permission to remove piers.

Table: Federal Model Standard vs. Texas Generic Used-Home Standard — 12 Verified Differences
Parameter	Federal (24 CFR Part 3285)	Texas generic (10 TAC Chapter 80)
Rule scope used here	Initial installation of new manufactured homes	One permitted installation method for used manufactured homes
Main frame geometric cap	120 in (10 ft) o.c. under §3285.310(c)	8 ft for 8-in beam, 10 ft for 10-in beam, 12 ft for 12-in beam; subject to shorter capacity result
No-perimeter configuration	Table 1 publishes loads through the 10-ft outer row	Separate table stops at 8 ft for 12-, 14- and 16-ft widths; 18-ft section requires perimeter support
Table indexing	Max 16-ft nominal section width assumption	Rows by 12-, 14-, 16- and 18-ft unit width
End-pier placement	No more than 24 in from both ends	No more than 24 in from the end of the main frame
Obstruction or redistribution	Up to 6 in offset shown in federal figures	Listed spacing may be exceeded up to 30% only when total pier count remains unchanged
MH and CH soil values	1,000 psf	1,500 psf
Unknown-soil default	1,500 psf unless site information indicates lower	No equivalent default; exact soil type must be determined by a certified laboratory
Single-stack block-pier height	Less than 36 in	Texas Pier A detail: 36-in height limit
Double-stack block-pier height	36 through 67 in	Texas Pier B: 48 in; greater heights follow adopted federal limits
Minimum clearance	12 in from lowest main-frame member to grade	18 in from ground to bottom of floor joists
Sidewall-opening perimeter support	Both sides of openings 48 in or more and listed concentrated loads	Both sides of openings over 4 ft; not required at endwalls

Source: ★ current 24 CFR Part 3285 and TDHCA 10 TAC Chapter 80 compilation effective December 21, 2025. Verified July 28, 2026.

7. Texas Pier Spacing Crosswalk

Texas publishes footer capacities and required pier loads in separate tables. This page joins every published combination into 380 calculated rows covering four footer sizes, five soil-bearing values, four home widths where applicable, three I-beam depths and three support configurations. Three rows have no supported value at the smallest listed spacing, and the dataset keeps those rows.

The Texas tables contain no interpolation instruction. The crosswalk selects the largest listed spacing whose required pier load does not exceed the listed footer capacity and applies the Texas I-beam-depth cap where it controls.

Texas identifies 16×16×4 as the typical pier-pad size in its generic standard. The crosswalk tables below isolate that footer across the published soil classes and support configurations.

Worked Examples

Example 1 — 16-ft-wide single section on 16×16×4 footers at 1,500 psf: footer capacity 2,700 lb; required at 4 ft is 2,350 lb (fits), at 5 ft is 2,900 lb (exceeds 2,700 lb); result is 4 ft. Texas publishes the same result.

Example 2 — 16-ft section with 12-in I-beam, same footer and soil: main-frame load at 8 ft is 2,400 lb (fits), at 10 ft is 3,000 lb (exceeds 2,700 lb); main-frame result is 8 ft. Perimeter at 8 ft is 2,500 lb (fits); perimeter result is 8 ft. Texas publishes same answers.

Crosswalk: No-Perimeter Configuration (16×16×4 footer)

Table: Texas Crosswalk — No-Perimeter Support, 16×16×4 Footer, Maximum Supported Spacing by Section Width and Soil
Section width	1,000 psf	1,500 psf	2,000 psf	2,500 psf	3,000+ psf
12 ft	no supported listed spacing	6 ft	8 ft	8 ft	8 ft
14 ft	no supported listed spacing	5 ft	7 ft	8 ft	8 ft
16 ft	no supported listed spacing	4 ft	6 ft	7 ft	8 ft

Source: ● Calculated from ★ 10 TAC §80.23(f)(2) load table and ★ 10 TAC §80.23(a) footer capacity table. Verified July 28, 2026. Rows with no supported listed spacing retain that notation.

Crosswalk: Main Frame with Perimeter Support (16×16×4 footer)

Values shown as 8-in beam / 10-in beam / 12-in beam spacing (ft).

Table: Texas Crosswalk — Main Frame with Perimeter Support, 16×16×4 Footer (8-in / 10-in / 12-in I-beam)
Section width	1,000 psf	1,500 psf	2,000 psf	2,500 psf	3,000+ psf
12 ft	8 / 8 / 8	8 / 10 / 12	8 / 10 / 12	8 / 10 / 12	8 / 10 / 12
14 ft	6 / 6 / 6	8 / 10 / 10	8 / 10 / 12	8 / 10 / 12	8 / 10 / 12
16 ft	4 / 4 / 4	8 / 8 / 8	8 / 10 / 10	8 / 10 / 12	8 / 10 / 12
18 ft	4 / 4 / 4	6 / 6 / 6	8 / 8 / 8	8 / 10 / 12	8 / 10 / 12

Source: ● Calculated from ★ 10 TAC §80.23(f)(3) main-frame load table and ★ 10 TAC §80.23(a) footer capacity table, with I-beam depth cap applied. Verified July 28, 2026.

Crosswalk: Perimeter Pier Spacing (16×16×4 footer)

Table: Texas Crosswalk — Perimeter Pier Maximum Spacing, 16×16×4 Footer
Section width	1,000 psf	1,500 psf	2,000 psf	2,500 psf	3,000+ psf
12 ft	7 ft	8 ft	8 ft	8 ft	8 ft
14 ft	6 ft	8 ft	8 ft	8 ft	8 ft
16 ft	5 ft	8 ft	8 ft	8 ft	8 ft
18 ft	4 ft	7 ft	8 ft	8 ft	8 ft

Source: ● Calculated from ★ 10 TAC §80.23(f)(3) perimeter load table and ★ 10 TAC §80.23(a) footer capacity table. Verified July 28, 2026.

8. Texas Source Tables

The crosswalk above is reproducible because the four official source tables are retained below. They appear in 10 TAC §80.23 as published in TDHCA’s current rules compilation effective December 21, 2025; the §80.23 section itself carries an effective date of January 20, 2009.

Texas Footer Capacity by Size and Soil

Table: Texas Footer Capacity (lb) by Footer Size and Soil Bearing Capacity — ★ 10 TAC §80.23(a)
Footer size	1,000 psf	1,500 psf	2,000 psf	2,500 psf	3,000+ psf
16×16×4 in	1,700	2,700	3,500	4,400	5,300
20×20×4 in	2,700	4,100	5,500	6,900	8,300
16×32×4 in	3,500	5,200	6,800	8,600	10,400
24×24×4 in	4,000	6,000	8,000	10,000	12,000

Source: ★ 10 TAC §80.23(a), verified July 28, 2026.

Texas No-Perimeter Frame-Pier Loads

Table: Required Frame-Pier Loads (lb) — Texas No-Perimeter Configuration — ★ 10 TAC §80.23(f)(2)
Unit width	4 ft o.c.	5 ft o.c.	6 ft o.c.	7 ft o.c.	8 ft o.c.
12 ft wide	1,725	2,150	2,600	3,000	3,400
14 ft wide	2,000	2,500	3,000	3,500	4,000
16 ft wide	2,350	2,900	3,500	4,100	4,700

Source: ★ 10 TAC §80.23(f)(2), verified July 28, 2026.

Texas Main Frame Loads with Perimeter Support

Table: Required Main Frame-Pier Loads (lb) — Texas with Perimeter Support — ★ 10 TAC §80.23(f)(3)
Unit width	4 ft o.c.	6 ft o.c.	8 ft o.c.	10 ft o.c.	12 ft o.c.
12 ft wide	750	1,150	1,500	1,900	2,300
14 ft wide	1,050	1,600	2,100	2,600	3,100
16 ft wide	1,200	1,800	2,400	3,000	3,600
18 ft wide	1,450	2,150	2,850	3,600	4,300

Source: ★ 10 TAC §80.23(f)(3), verified July 28, 2026.

Texas requires a licensed installer to retain an installation checklist that includes verification of site soil conditions and pier-spacing calculation per 10 TAC §80.33(j)(2)–(3).

Texas Perimeter Pier Loads

Table: Required Perimeter Pier Loads (lb) — ★ 10 TAC §80.23(f)(3)
Unit width	4 ft o.c.	5 ft o.c.	6 ft o.c.	7 ft o.c.	8 ft o.c.
12 ft wide	1,000	1,200	1,500	1,700	1,900
14 ft wide	1,100	1,400	1,650	1,900	2,200
16 ft wide	1,300	1,600	1,900	2,250	2,500
18 ft wide	1,600	2,000	2,300	2,700	3,000

Source: ★ 10 TAC §80.23(f)(3), verified July 28, 2026.

9. Support Types and Load Paths

A pier-spacing number applies to one support location and one load path at a time. At 10-foot spacing and a 40 psf roof live load in federal Table 2, the frame pier carries 2,900 lb, the perimeter pier 6,000 lb and the mating-wall support 10,600 lb — a 3.7-fold range under the same tabulated spacing.

Frame Piers

Frame piers sit under the main I-beams that form the chassis. The federal 120-inch outer limit and the two federal calculated charts on this page address the frame-pier row.

Perimeter Piers

Perimeter piers sit under the outside floor rail. The federal standard requires them at the listed sidewall openings and concentrated loads, including both sides of sidewall exterior doors, patio and sliding-glass doors, other sidewall openings 48 inches or wider and certain factory-installed loads. Texas triggers opening support at sidewall openings over four feet and states that opening perimeter piers are not required at endwalls. Under §3285.307, a federal perimeter pier using a single 8×8×16 block is limited to 54 inches in height.

Marriage-Line (Mating-Wall) Supports

Marriage-line or mating-wall supports sit along the seam between sections of a multi-section home. Federal supports are not required at mating-wall openings under 48 inches; openings 48 inches or wider require support on both sides. Texas §80.23(i)(3) sets marriage-wall pier spacing equal to main I-beam spacing without perimeter piers and at one-half the perimeter-pier spacing when perimeter piers are installed.

Pier Spacing vs. Tie-Down Spacing

Piers transfer vertical gravity loads to the ground. Anchors and tie-downs resist uplift and lateral movement from wind. The systems are governed by different tables and rules and cannot substitute for each other. Texas addresses piers in §80.23 and anchoring systems in §80.24. One verified point of contact is §80.24(e)(2)(C): where a tie location is clearly marked as a shear-wall strap, a perimeter pier must be installed at that location. This page does not publish anchor spacing, strap angles, tie-down layouts, jacking, cribbing or blocking procedures.

10. Other State Divergences

Mississippi’s current factory-built-home rule, effective July 1, 2026, gives a verified example of state requirements for used homes that differ from both the federal new-home model standard and the Texas generic method. Its values change with home width, section count, wind zone and whether soil bearing capacity reaches 2,000 psf. For a new home, Mississippi’s rule starts with the manufacturer’s installation instructions. This table is deliberately limited to the federal model standard, Texas and Mississippi. It does not represent a completed 50-state survey.

Table: State and Federal Maximum Frame-Pier Spacing — Selected Verified Jurisdictions
Jurisdiction and scope	Maximum frame-pier spacing	End-pier rule	Primary verification
Federal model standard, initial installation of new homes	120 in (10 ft) o.c. outer limit	No more than 24 in from both ends	★ 24 CFR §§3285.1 and 3285.310
Texas generic method for used homes	8 ft without perimeter support; 8/10/12 ft with perimeter by beam depth, subject to shorter result	No more than 24 in from main-frame end	★ 10 TAC §§80.21 and 80.23
Mississippi used single-section, soil ≥2,000 psf	8 ft at 14 ft wide or less; 6 ft over 14 ft wide	1 to 2 ft from each I-beam end	★ Mississippi Regulation MH-5, Rule 5.06.8
Mississippi used single-section, soil <2,000 psf	4 ft	1 to 2 ft from each I-beam end	★ Mississippi Regulation MH-5, Rule 5.06.8
Mississippi used multi-section or used Wind Zone II	6 ft	1 to 2 ft from each I-beam end	★ Mississippi Regulation MH-5, Rule 5.06.8

Source: ★ current primary rules. Mississippi MH-5 effective July 1, 2026. All rows verified July 28, 2026.

11. Coastal Texas and Corpus Christi Notes

Components used near the coastline: Under 10 TAC §80.21(d), nonconcrete stabilizing components and systems used within 1,500 feet of the coastline must be specifically certified for that use, and anchors must be resistant to corrosion. The rule defines coastline by reference to the Gulf shoreline and qualifying connected bays or estuaries.
Nueces County is Wind Zone II: Texas Occupations Code §1201.256 lists Nueces County in Wind Zone II. Wind zone governs the anchoring and stabilization system rather than the gravity-load spacing tables. Texas §80.24 provides the verified connection: a perimeter pier is required at a location clearly marked as a shear-wall strap.
Mapped Special Flood Hazard Areas: Corpus Christi’s official Floodplain Development Permit states that a permit is required for development in a mapped Special Flood Hazard Area. The federal pier-load tables do not account for flood loads, and §3285.302 addresses flood-resistant foundation information separately. See the City of Corpus Christi Flood Maps for current SFHA boundaries.
Site soil must be established: Texas permits the soil-bearing determination methods stated in §80.23 and says its soil-type chart is informational, with exact soil type determined by a certified laboratory. The rule requires footers to bear on firm undisturbed soil or fill compacted to at least 90% of maximum relative density. This page does not assign a soil class to a Corpus Christi parcel.

Installation and releveling are licensed activities in Texas. TDHCA’s official licensing notice states that installation and releveling require a licensed and bonded installer. For more information on pier and support repair in Corpus Christi, see the service page.

12. Methodology

Every official value on this page was checked against a primary government source on July 28, 2026. The original evidence consists of two reproducible joins: 204 federal calculated rows across two support cases and a 380-row Texas generic used-home crosswalk.

Federal Sources

The current eCFR text of 24 CFR Part 3285 was checked section by section, including §§3285.1, 3285.2, 3285.202, 3285.303, 3285.305–3285.307 and 3285.310–3285.312. The federal load tables were also checked against the 2025 annual CFR edition on GovInfo. HUD’s official Manufactured Home Installation Program FAQ was used for the agency’s published interpretation of the Table 3 wording conflict.

Texas Sources

Texas figures were read from TDHCA’s current Manufactured Housing Rules compilation effective December 21, 2025. Section 80.23 within that compilation carries an effective date of January 20, 2009.

Mississippi Source

The state comparison uses Mississippi Regulation MH-5 effective July 1, 2026. That current primary publication supersedes the older 2015/2016 rule citation.

Federal Calculation Method

For each soil and footing row in the 8×16 pier column of the §3285.312 unreinforced cast-in-place footing table, governing capacity is the lesser of the published footing capacity and the 8,000 lb single-stack pier limit. That governing capacity is solved against §3285.303 Table 1 for the frame-only case and Table 2 for the frame-plus-perimeter case. Linear interpolation is used only between the published four-, six-, eight- and 10-foot rows. Every value is then capped at 120 inches under §3285.310(c). Files floor interpolated maximums to the lower whole inch.

Texas Calculation Method

For every Texas combination, the crosswalk selects the largest published spacing whose required pier load does not exceed the published footer capacity. No interpolation is used. Main I-beam rows with perimeter support are additionally capped at 8, 10 or 12 feet for 8-, 10- or 12-inch beams.

Quality Checks

102 federal rows for the frame-only case
102 federal rows for the frame-plus-perimeter frame-pier case
34 federal soil-and-footing combinations
19 federal combinations governed by the 8,000 lb single-stack pier cap
380 Texas crosswalk rows (60 no-perimeter, 240 perimeter-supported main-frame across three beam depths, 80 perimeter-pier)
Exactly three Texas rows with no supported listed spacing
Reproduction of both worked examples in the Texas rule
Exact 8,000 lb federal interpolation verified: between 6,900 lb at 8 ft and 8,500 lb at 10 ft, 8,000 lb resolves to 9.375 feet (112.5 inches)

No official source value was estimated, imputed or replaced. Interpolated federal values and joined Texas values are labeled ● calculations. Source-table values remain ★ values.

13. Limitations

1. This is a reference chart, not a foundation design. It cannot establish the correct spacing for a particular home on a particular property.
2. The federal 10-foot figure is an outer maximum, not a default or recommendation. The calculated federal rows include cases with no supported result at the smallest four-foot Table 1 row.
3. The manufacturer’s DAPIA-approved installation instructions govern where they apply. Under 24 CFR §3285.2, a new home’s approved instructions are the controlling starting document.
4. 24 CFR Part 3285 covers the initial installation of new manufactured homes. It does not itself create a releveling standard for an already-installed home.
5. The federal derived chart models one specified pier and footing basis. It uses a single-stack 8×16 concrete-block pier and the 8×16 pier column of the unreinforced cast-in-place footing table.
6. The federal tables carry stated design assumptions. Tables 1 and 2 include a maximum 16-ft nominal section width, a 10-in I-beam and specified dead loads; Table 3 has its own stated assumptions.
7. The federal tables exclude flood and seismic loads. They are not intended as the generic design tables for those hazard areas.
8. The Texas crosswalk applies only when the Texas generic used-home method controls. It does not apply to new Texas homes, registered systems, specially designed systems or homes outside Texas.
9. Texas calls its soil-type chart informational and requires exact soil type to be determined by a certified laboratory. The page does not infer a site’s structural soil value from appearance or location.
10. The current federal Table 3 contains a wording conflict. HUD’s official FAQ says Figure C Note 2 is correct and the loads are totals for both sections; the CFR table note still says “each section.” Both facts remain visible.
11. The current eCFR soil table prints “CG, MH” in class 4A while Note 2 to the same table refers to CH and MH. This page preserves the printed symbol rather than silently correcting the federal text.
12. State coverage is deliberately limited. Federal, Texas and current Mississippi provisions are included. The page does not claim a completed 50-state survey.
13. Pier spacing and anchor spacing are different systems. Nothing here supplies an anchor count, tie-down spacing, strap angle or wind-resistance design.
14. The page provides no jacking, cribbing, shimming, blocking, anchor-installation or releveling procedure. Lifting and supporting a dwelling is work for qualified professionals.
15. The displayed verification date changes only after the cited sources and generated outputs are rechecked.

Figures Deliberately Not Published

No primary measurement was verified for a national average pier spacing, a universal pier count, a national percentage with improper spacing, or a national failure rate attributable to pier spacing. The “six to eight feet” range is not presented as a standard — the verified provisions show why no single range can answer every installation.

14. How to Cite This Page

The attribution block below identifies the organization, page, version and verification date in a neutral format that can be adapted to the reader’s citation style. Derived values should be described as calculated results, while official values remain attributable to the issuing government source listed in the source line beneath each table.

Publication: Corpus Christi Mobile Home Leveling Research
Page title: Mobile Home Pier Spacing Chart
Dataset title: Mobile Home Pier Spacing: Federal Calculated Spacing and Texas Pier Spacing Capacity Crosswalk
Dataset version: 2026.07.28.1
URL: https://corpuschristimobilehomeleveling.com/research/mobile-home-pier-spacing-chart/
Last verified: July 28, 2026
Access date: Reader’s access date

Which dataset files accompany the page?

Table: Dataset Files Available for Download
File	Format	Rows	Contents
Federal frame-only calculation	CSV	102	Soil, footing, material and thickness, published capacity, pier cap, governing capacity, roof load, exact spacing, conservative display, interpolation brackets, source and date
Federal frame-plus-perimeter	CSV	102	Same structure using Table 2 frame-pier loads
Texas pier spacing crosswalk	CSV	380	Support system, location, width, beam depth, footer, soil, loads, selected spacing, next row, status, source and date
Dataset metadata	JSON	—	Dataset identity, version, methods, limitations, source list, distributions and quality checks

15. Dataset Download

Federal Frame-Only CSV (102 rows)Federal Frame+Perimeter CSV (102 rows)Texas Crosswalk CSV (380 rows)Dataset Metadata JSON

16. Frequently Asked Questions

How far apart should mobile home piers be?

Under the federal model installation standards, frame piers go no more than 120 inches, or 10 feet, on center under the main rails and no more than 24 inches from both ends of the home. That is an outer limit. The supported spacing for a particular installation depends on the controlling instructions, roof live load, soil bearing capacity, footing size, pier type, support configuration, openings and site conditions.

Is 10 feet always allowed between mobile home piers?

No. Under federal Table 1, the required frame-pier load at 10 feet is 6,800 to 8,500 pounds depending on roof live load. At 40 psf, the 8,500-pound requirement exceeds the 8,000-pound design-capacity limit for a single-stack 8 by 16 concrete-block pier, and footing or soil capacity can require a shorter spacing at any roof live load.

What does “on center” mean in a pier spacing rule?

On center means the distance is measured from the center of one pier to the center of the next, rather than from one outside edge to another. The common abbreviation is o.c.

Is six to eight feet the standard mobile home pier spacing?

No federal or Texas provision verified for this page establishes six to eight feet as a universal standard. The federal model standard has a 10-foot outer limit for its new-home installation scope, while the Texas generic used-home tables publish results from 4 to 12 feet depending on support configuration, home width, I-beam depth, soil and footing capacity.

How does soil bearing capacity affect pier spacing?

Soil bearing capacity limits how much load a footing of a given size can transfer to the ground. In the federal 8 by 16 pier column, a 16 by 16 unreinforced cast-in-place footing carries 1,600 pounds at 1,000 psf soil and 7,000 pounds at 4,000 psf soil; the corresponding minimum cast-in-place thickness is six inches in both rows.

Does a bigger footing always allow wider pier spacing?

No. Once a footing capacity exceeds the 8,000-pound design-capacity limit for a single-stack 8 by 16 concrete-block pier, that pier cap becomes the binding constraint. It controls 19 of the 34 federal soil-and-footing combinations used in this page’s single-stack calculation.

Does a double-wide use the same pier spacing chart as a single-wide?

Not entirely. Multi-section homes also have mating-line or marriage-line supports, and openings along that line carry separate federal loads. Texas likewise gives marriage-wall support its own relationship to main-frame and perimeter spacing, so a frame-pier number cannot be applied to every support under a multi-section home.

Are pier spacing and tie-down spacing the same?

No. Piers transfer vertical gravity loads to the ground. Anchors and tie-downs resist uplift and lateral movement from wind, are governed by different provisions and cannot substitute for the pier and footing system.

Which chart applies to a new manufactured home in Texas?

The manufacturer’s DAPIA-approved installation instructions apply. Under 10 TAC §80.21(a), a new manufactured home must be installed by a licensed installer according to those instructions; the Texas generic standards used in this page’s crosswalk are one permitted method for used homes.

Does the Texas crosswalk apply outside Texas?

No. It is derived from the Texas generic standards and is limited to the situation in which that used-home installation method controls. Other jurisdictions can use different requirements, and a manufacturer’s instructions, registered system or site-specific engineered design can control instead.

How many piers should be under a mobile home?

Home length alone cannot produce a reliable count. The answer also depends on both main rails, end offsets, the supported spacing, perimeter support, mating-line supports, sidewall and marriage-line openings, concentrated loads and the controlling installation method.

Do flood or coastal conditions change the answer?

Yes. The federal pier-load tables state that they do not account for flood or seismic loads. In Texas, nonconcrete stabilizing components and systems used within 1,500 feet of the coastline must be specifically certified for that use, and a Corpus Christi project in a mapped Special Flood Hazard Area is subject to the city’s floodplain-development requirements.

17. Sources

All 19 sources listed below are primary government publications verified July 28, 2026. ★ marks source-table values throughout the page.

Last verified: July 28, 2026

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