Ohio Admin. Code 4781-6-03.3 - Foundations
(A) General.
(1) Foundations for manufactured home
installations shall be designed and constructed in accordance with this subpart
and shall be based on site conditions, home design features, and the loads the
home was designed to withstand as shown on the home's data plate.
(2) Foundation systems that are not pier and
footing type configurations may be used when verified by engineering data and
designed in accordance with this rule and consistent with the design loads of
the MHCSS. Pier and footing specifications,
that are different than those provided in this rule, such as block size, metal
piers, section width, loads, and spacing, may be used when verified by
engineering data that comply with this rule and are capable of resisting all
design loads of the MHCSS.
(3)
Details, plans, and test data shall be designed and certified by an Ohio
registered professional engineer or registered architect, and shall not take
the home out of compliance with the MHCSS.
(4) Alternative foundation systems.
Alternative foundation systems or designs are permitted when they do not take
the home out of compliance with the MHCSS and
when they are in accordance with either of the following:
(a) Engineered foundation systems or designs
shall be manufactured and installed in accordance with their listings by a
nationally recognized testing agency based on a nationally recognized testing
protocol; or
(b) System designs
shall be prepared by an Ohio registered professional engineer or a registered
architect in accordance with acceptable engineering practice.
(B) Flood hazard areas.
(1) In flood hazard areas, the foundation,
anchoring, and support systems shall be capable
of resisting loads associated with design flood and wind events, and homes
shall be installed on foundation supports that are designed and anchored to
prevent floatation
flotation, collapse, or
lateral movement of the structure. The manufactured home shall be installed in
accordance with the manufacturer's instructions where available. If the
foundation system being used is not covered by the manufacturer's instructions,
the foundation system shall be designed by an Ohio registered professional
engineer or registered architect.
(2) Where manufacturer's installation
instructions do not address flood loads or flood hazard areas, the requirements
of the authority having jurisdiction, the floodplain authority, FEMA 85,
44 C.F.R. 60.3(a) to (e)
(Feb. 8, 1984), other provisions of 44
C.F.R.60
C.F.R.
60 referenced by those paragraphs, Chapter 1521. of the Revised Code, and
division
Chapter 1501:22-1 of the
Administrative Code shall govern.
(C) Piers.
(1) General. The piers used shall be capable
of transmitting the vertical live and dead loads to the footings or
foundation.
(2) Acceptable piers,
materials speciftication
specification.
(a)
Piers are permitted to be concrete blocks; hardwood or other listed and
approved shims, spacers, or caps, or with pressure-treated wood shims, spacers, or caps with a water borne preservative, in
accordance with the American wood
preserver's
protection association's (AWPA) "Standard U1 for Use
Category 4B" ground contact applications; or adjustable metal or concrete
piers.
(b) Manufactured piers shall
be listed or labeled for the required vertical load capacity, and, where
required by design, for the appropriate horizontal load capacity. Manufactured
piers shall be installed with an approved footing and in accordance with their
listing or pier manufacturer's installation instructions.
(3) Design requirements.
(a) Load bearing capacity. The load bearing
capacity for each pier shall be designed to included
include
consideration for the dimensions of the home, the design dead and live loads,
the spacing of the piers, and the way the piers are used to support the home.
(b) Center beam/mating wall
support shall be required for multi-section homes, and designs shall be consistent with tables 3.2 and
3.3 of this rule and figures 3E, 3F, and 3G of
this rule.
(4) Pier
loads.
(a) Design support configurations and
footing sizes for the pier loads, pier spacing, and roof live loads shall be in
accordance with tables 3.1, 3.2, and 3.3 and the MHCSS. Other pier and footing
designs are permitted in accordance with the provisions of Chapter 4781. of the
Revised Code.
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(b)
Manufactured piers shall be rated at least to the loads required to safely
support the dead and live loads as required by this rule and the installation
instructions for those piers shall be consistent with tables 3.1, 3.2, and 3.3 of this rule.
(D) Pier configuration.
(1) Concrete blocks. Installation
instructions for concrete block piers shall be developed in accordance with the
following provisions and shall be consistent with figures 3A and 3B of this
rule.
(a) Load-bearing concrete blocks meeting
ASTM C-90 shall be used and shall have nominal dimensions of at least eight
inches by eight inches by sixteen inches and an average net area minimum
compressive strength for three units of nineteen hundred psi;
(b) The concrete blocks shall be stacked with
their hollow cells aligned vertically; and
(c) When piers are constructed of blocks
stacked side by side, each layer shall be at right angles to the preceding one,
as shown in figure 3B of this rule.
(2) Caps.
(a) Structural loads shall be evenly
distributed across capped hollow block piers, as shown in figures 3A and 3B of
this rule.
(b) Caps shall be solid
concrete or masonry at least four inches in nominal thickness, or hardwood
lumber at least two inches nominal in thickness; or be corrosion-protected
minimum one-half inch thick steel; or be of other listed materials. ACQ treated
lumber shall not have direct contact with I-beams. Roofing felt, six mil
plastic, or equal may be used as a barrier between ACQ caps and the
I-beam.
(c) All caps shall be of
the same length and width as the piers on which they rest.
(d) When split caps are used on
double-stacked blocks, the caps shall be installed with the long dimension
across the joint in the blocks below.
(3) Gaps. Any gaps that occur during
installation between the main chassis beam and foundation support system shall
be filled.
(a) Nominal four inch by six inch
by one inch shims are permitted to be used to level the home and fill any gaps
between the base of the main chassis beam and the top of the pier
cap.
(b) Shims shall be used in
pairs as shown in figures 3A and 3B of this rule and shall be driven in tightly
so that they do not occupy more than one inch of vertical height.
(c) Hardwood plates no thicker than two
inches nominal in thickness or four inches nominal concrete block must be used
to fill any remaining vertical gaps.
(d) Gap fill materials, not made of masonry,
shall not exceed three inches, by a combination of nominal two by eight wood
block and one set of one- inch wood wedges or
shims.
(4) Manufactured
pier heights. Manufactured pier heights shall be selected so that the
adjustable risers do not extend more than two inches when finally
positioned.
(E)
Clearance under homes.
(1) A minimum clearance
of twelve inches shall be maintained between the lowest member of the main
frame I-beam or channel beam) and the grade under all areas of the home. No
more than twenty-five per cent of the lowest member of the main frame of the
home shall be less than eighteen inches above grade.
(2) A minimum clearance of eight inches shall
be maintained between the bottom of the lowest wood frame member and the
exterior grade.
(F)
Design procedures for concrete block piers.
(1) Frame piers less than thirty-six inches
high.
(a) Frame piers less than thirty-six
inches high shall be permitted if constructed of single, open, or closed-cell
concrete blocks, eight inches by eight inches by sixteen inches, when the
design capacity of the block is not exceeded.
(b) The frame piers shall be installed so
that the long sides are at right angles to the supported I-beam, as shown in
figure 3A of this rule.
(c) The
concrete blocks shall be stacked with their hollow cells aligned vertically and
shall be positioned at right angles to the footings.
(d) Horizontal offsets from the top to the
bottom of the pier shall not exceed one-half inch.
(e) Mortar is not required unless specified
in the installation instructions or required by an Ohio registered professional
engineer or registered architect. Where mortar is required, minimum type S
mortar shall be used.
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(2) Frame piers thirty-six inches to
sixty-seven inches high and corner piers.
(a)
All frame piers between thirty-six and sixty-seven inches high and corner piers
over three blocks high shall be constructed out of double, interlocked concrete
blocks as shown in figure 3B of this rule, when the design capacity of the
block is not exceeded. Mortar is not required for concrete block piers unless
otherwise specified in the installation instructions or required by an Ohio
registered professional engineer or registered architect. Where mortar is
required, minimum type S mortar shall be
used.
(b) Horizontal offsets from
the top to the bottom of the pier shall not exceed one-half inch.
(3) Pier tolerances. Piers shall
be plumb and level with tolerances per figure 3D of this rule.
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(4)
All piers over sixty-seven inches high. Unless the manufacturer's installation
instructions specifically contains
contain a design, piers over sixty-seven inches high
shall be designed by an Ohio registered professional engineer or registered
architect in accordance with acceptable engineering practice. Mortar is not
required for concrete block piers unless otherwise specified by the design.
Where mortar is required, minimum type S mortar shall be used.
(G) Perimeter support piers.
(1) Piers required
at mate-line supports, perimeter piers, and piers at exterior wall openings
shall be permitted to be constructed of single open-cell or closed-cell
concrete blocks, with nominal dimensions of eight inches by eight inches by
sixteen inches, to a maximum height of fifty-four inches, as shown in figure 3A
of this rule, when the design capacity of the block is not exceeded.
(2) Piers used for perimeter support shall be
installed with the long dimension parallel to the perimeter rail.
(H) Manufactured piers.
Manufactured piers shall be listed and labeled and installed to the pier manufacturer's installation instructions. See this rule for additional requirements.
(I) Piers over sixty-seven inches high.
Piers over sixty-seven inches high must be designed by an Ohio registered professional engineer or registered architect, in accordance with acceptable engineering practice.
(J) Pier location and spacing.
(1) The location and spacing of piers depends
upon the dimensions of the home, the live and dead loads, the type of
construction (single- or multi-section), I-beam size, soil bearing capacity,
footing size, and such other factors as the location of doors or other
openings.
(2) Mate-line and column
pier supports shall be in accordance with this rule and consistent with figures
3E to 3G of this rule.
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(3)
Piers supporting the frame shall be no more than twenty-four inches from both
ends and not more than ninety-six inches from center to center under the main
rails. If the piers supporting the frame is more than ninety-six inches, but
not more than one hundred twenty inches, from the center to center under the
main rails, the increased dimensions shall be approved by an Ohio professional
engineer or registered architect or in accordance with the
manufactured
manufacturer's installation manual.
(4) Pier support locations. Pier support
locations and spacing shall be presented to be consistent with figures 3H and
3I of this rule, as applicable, unless alternative designs are provided by a
professional engineer or registered architect in accordance with acceptable
engineering practice.
(K) Required perimeter supports. Perimeter
pier or other supports shall be located as follows:
(1) On both sides of side wall exterior doors
(such as entry, patio, and sliding glass doors) and any other side wall
openings of forty-eight inches or greater in width, and under load-bearing
porch posts, factory installed fireplaces, and wood stoves.
(2) Other permiter
perimeter
supports shall be:
(a) Located in accordance
with table 3.2 of this rule.
(b)
Provided by other means such as additional outriggers or floor joists. When
this alternative is used, the designs required by this rule shall consider the
additional loads in sizing the pier and footing supports under the main chassis
beam.
(L)
Footings.
(1) Materials approved for footings
shall provide equal load-bearing capacity and resistance to decay as required
by this rule. Footings shall be placed on undisturbed soil or fill compacted to
ninety per cent of maximum relative density. A footing shall support every
pier.
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(2)
Acceptable types of footings.
(a) Concrete.
Footings are to be either:
(i) Four inch
nominal precast concrete pads meeting or exceeding "ASTM C
90-02
90,
Standard Specification for Load Bearing Concrete Masonry Units," without
reinforcement, with at least a twenty-eight day compressive strength of three
thousand pounds per square inch (psi);
(ii) Six inch minimum poured-in-place
concrete pads, slabs, or ribbons with at least a twenty-eight day compressive
strength of three thousand pounds per square inch (psi). Cast-in-place concrete
footings may also require reinforcing steel based on acceptable engineering
practice, the design loads, and site specific soil conditions. Poured footings
shall be level and screeded smooth; or
(iii) Footing tolerances. Improper footings
as illustrated in figure 3J shall not be approved.
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(b) Engineered plastic composite footing
pads.
(i) Engineered plastic composite footing
pads shall be permitted if used in accordance with the manufacturer's installation instructions and/or specification
sheet of the specific engineered plastic composite pad being used. The use of
engineered plastic composite pads must be used in conjunction with solid
perimeter skirting in accordance with paragraphs (D)(1) to (D)(4) and (E)(1) to
(E)(6) of rule 4781-6- 02.5
4781-6-
03.5 of the Administrative Code.
(ii) Engineered plastic composite footing
pads shall be listed or labeled for the required load capacity and installed in
accordance with their listing.
(c) Placement in freezing climates. Footings
placed in freezing climates shall be designed using methods and practices that
prevent the effects of frost heave by one of the following methods:
(i) Conventional footings shall be placed
below the frost line depth for the site unless an insulated foundation or
monolithic slab is used in this rule. When the frost line depth is not
available from the authority having jurisdiction, a registered professional
engineer, registered architect, or registered geologist shall be consulted to
determine the required frost line depth for the manufactured home
site.
(ii) Monolithic slab systems.
A monolithic slab may be permitted above the frost line when all relevant
site-specific conditions including soil characteristics, site preparation,
ventilation, and insulative properties of the under floor enclosure are
considered and anchorage requirements as set for in rule
4781-6- 02.4
4781-6-
03.4 of the Administrative Code, and the
monolithic slab system shall be designed by an Ohio registered professional
engineer or registered architect:
(a) In
accordance with acceptable engineering practice to prevent the effects of frost
heave; or
(b) In accordance with
ASCE/SEI 32-01. The design shall accommodate the anchorage requirements set out
in rule 4781-6- 02.4
4781-6- 03.4 of the Administrative Code.
(iii) Insulated foundations. An
insulated foundation shall be permitted above the frost line, when all relevant
site-specific conditions including soil characteristics, site preparation,
ventilation, and insulative properties of the under floor enclosure are
considered and the foundation is designed by an Ohio registered professional
engineer or registered architect:
(a) In
accordance with acceptable engineering practice to prevent the effects of frost
heave; or
(b) In accordance with
ASCE/SEI 32-01. The design shall accommodate the anchorage requirements set out
in rule 4781-6- 02.4
4781-6- 03.4 of the Administrative Code.
(d) Sizing of footings.
The sizing of footings depends on the load-bearing capacity of the soil,
footings, and the piers as set forth in this rule.
(e) The size and capacity for un-reinforced
cast-in-place footings shall be in accordance with figure 3K of this rule.
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(M) Combination systems.
Support systems that combine both load-bearing capacity shall also be sized and designed for all applicable design loads.
(N) Permanent foundations.
Permanent foundations shall:
(1) Have a continuous perimeter wall that
complies with the requirements of HUD's September
1996 permanent foundation guide for manufactured homes;
(2) Have footings that are either below the
frost line or protected from frost heave;
(3) Tongue wheels, axles, and hitches shall
be removed from under the manufactured home; and
(4) Conform to Chapter 4781-6 of the
Administrative Code.
(O)
Stable foundation means:
Foundations not to frost depth but protected against frost heave by the installation properties of the under home enclosure and shall conform to Chapter 4781-6 of the Administrative Code.
(P) Temporary foundation means:
Footing not below frostline
frost line
or protected from frost heave and shall be permitted on private property for no
more than six months,
.
two
Two six- month
extensions may be granted by the authority having jurisdiction upon written
request if the installations
installation is in accordance with Chapter 4781-6 of
the Administrative Code.
(Q) Special
snow load conditions.
(1) In general,
foundations for homes, which
that by special request of the home owner are designed
for and located in areas with roof live loads greater than forty
pounds per square foot shall be designed by the
manufacturer for the special snow load conditions in accordance with acceptable
engineering practice. Where site or other conditions prohibit the use of the
manufacturer's instructions, a registered professional engineer or registered
architect shall design the foundation for the special snow load
conditions.
(2) Ramadas.
A ramada is any freestanding roof or shade
structure, nstalled or erected above a manufactured home or any portion there
of. Ramadas may be used and shall be self- supporting except that any
connection to the home shall be for weatherproofing only.
Notes
Promulgated Under: 119.03
Statutory Authority: 4781.04, 4781.14
Rule Amplifies: 4781.04, 4781.14
Prior Effective Dates: 09/15/2006, 01/01/2010, 06/02/2011, 12/01/2012
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