MH Installers
On-Line Continuing Education
Contents of this Course
Installation Standard applicable to PreApril 1, 2007 homes
 Requirements for steps
 Ramps, Steps and Handrails
 Refresher on Post-2007 Home Standards
 SPS 320 Code Enforcement Refresher
 Understanding Soils and Frost Heave

3 Primary Resources
Installation Codes
 UDC Codes
 Slides

Let’s Get Started
Act 45 laws of 2005 authorized the
Department Commerce (now
Department of Safety & Professional
Standards) to adopt installation standards.
 The UDC applies to both new and used
(relocated) homes. However, the
production date as shown on the data
plate determines which code applies.

Pre-2007 Home
In this course Pre-2007 means a home
build before April 1, 2007.
 The applicable code is fairly short and is
found in SPS 321.40. It is linked for you
on the course page at
www.housingalliance.us/InstalCE.htm

Pre-2007 Code
Anchoring is a preferred way to protect
the home from the wind. However, if the
home is not on a frost protected
foundation, anchors can damage the
home.
 Since frost protected foundations are not
required neither is anchoring.

Pre-2007

Soil Requirements – SPS 321.40(2)
◦ No footing may be placed on




Unprepared fill material
Top soil
Alluvial soil
Mud
◦ All organic material must be removed
Pre 2007
Soil bearing capacity must be determined
so that the footing can be properly sized.
 A pocket penetrometer is the least
expensive method

Controlling water is primarily
accomplished by grading the site.
 Unlike the federal code, grading for Pre
2007 home is only required for 5 feet
around the home. 10 feet however would
be preferred but again not required.

Footings
Once the soil bearing capacity is
determined the size of the footing can be
determined.
 The minimum footing size is 16 by 16
inches

Footings

If a ABS pad is used, its bearing capacity
for a 16 by 16 pad must be 6,000 lbs
Footings

There are 4 acceptable types of footings
◦ One nominal14 by 6 by 16 inch solid
concrete block or two nominal 4 by 8 by 16
inch blocks
◦ An 18 inch hole bored below the frost line or
to unfractured soil and filled with concrete
◦ A 16 by 16 inch ABS pad
◦ Any other Department approved systems
Piers
In a pier where a single block is at the top
of the pier with double blocks below, the
double blocks must be positioned with
their joint parallel to the main frame.
 If a double block pier is used, the two
footing blocks may be positioned with the
joint parallel or perpendicular to the main
frame.

Piers

A manufactured steel stand is accepted as
a pier. Check it’s load bearing capacity
however before use.
Pier Heights
Single stack piers are limited to 36 inches
 Above 36 inches up to 80 inches double
blocks with alternating orientations are
required.
 Above 80 inches mortar and ½ inch a
steel reinforcing rod is additionally
required
 There is no limit on height

Pier Placement
The maximum pier separation is 7 feet
 The piers must be plumb and centered
under the contact area at the point of
support
 The outside piers cannot be more than 3
feet from the exterior of the home.
 Additional piers are required in clear span
openings in exterior walls or openings in
mating walls of 4 or more feet

Blocks
Must be 2 core design. Cannot be 3 core
or solid.
 Cores are always placed vertically
 No concrete block can contact the main
frame

Caps


Since concrete piers cannot contact the
frame, a cap is required.
Acceptable caps are
◦ A solid concrete at least a nominal 2 inches
◦ A solid wood block at least a nominal 2 inches



The cap must be the same width and length
as the top of the pier
A two-piece cap shall be positioned with the
joint perpendicular to the frame
The combined height of the cap material
cannot exceed 3 ½ inches
Shims
Shims must have a dimension of at least 4
inches by 8 inches
 They must all be from the same species of
wood. (ABS shims are not allowed)
 Shims and caps must be at least equal to
No. 2 spruce pine and have a fiber
bending stress rating of 1200 psi or better
 Shims are to be driven in pairs from
opposing sides of the pier

Wood
Trees are divided into two classes
hardwoods and softwoods
 Hardwoods have broad leaves and
softwood have needles
 Hardwood/Softwood does not describe
the “hardness” of the wood
 Drying wood from green to 5 percent
moisture in some cases triples its
strength

Wood
Force applied to one side of a beam
creates compression on that side and is
way to measure strength
 The following woods have stress bending
rates high enough to meet the 1200 psi
rating

◦ Douglas Fir
◦ Hemlocks
◦ Spruce Pine Fir but only select, no. 1 or no. 2
Spruce Pine Fir no 3 would not be acceptable
Clearance
A minimum clearance of 12” shall be
maintained under at least 75% of the
home.
 (For homes built on or after 4/1/2007 the
entire clearance area must be 12”)

This is the end of the Pre-2007 Home Installation Code Section
Stairs, Steps, Railings – Consult SPS
321
Stairway leading to non-habitable attics or
crawl spaces are not covered by the UDC
 Generally, stairways must measure at least
36” in width

Spiral Stairs



Often not just a decorative feature but a space
necessity.
Spiral staircases shall be at least 26 inches wide
measured from the outer edge of the supporting
column to the inner edge of the handrail.
At the top and bottom of a flight, measurement shall be
taken from the top of the nosing to the finished floor
surface unless the finished surface is carpeting, in which
case measurement shall be made to the hard surface
below the carpeting.
Except for spiral staircases risers may not
exceed 8 inches in height measured
vertically from tread to tread.
 Risers in spiral staircases may not exceed
9.5 inches in height measured vertically
from tread to tread.
 Rectangular treads shall have minimum
tread depth of 9 inches measured
horizontally from nosing to nosing.

Headroom


Stairways shall be provided with a minimum headroom
clearance of 76 inches measured vertically from a line
parallel to the nosing of the treads to the ceiling, soffit
or any overhead obstruction directly above that line.
The headroom clearance shall be maintained over a
landing that is at the top or bottom of a stairway for a
minimum distance of 36 inches in the direction of
travel of the stairway.
Variance in Height
Within a stairway flight,
the greatest tread depth
may not exceed the
smallest tread depth by
more than 3/8 inch and
the greatest riser height
may not exceed the
smallest riser height by
more than 3/8 inch.
WOW!
The walking surface of stair treads and
landings shall be a planar surface that is
free of lips or protrusions that could
present a tripping hazard.
 Stairways leading to non-habitable attics
or crawl spaces are not covered by the
UDC.
 Generally, stairways shall be at least 36
inches wide.

Common Defects
Openings in handrails/guardrails
 Gripping surfaces on handrails
 Headroom
 Uniformity
 Landings

Cable or Ropes

If cables or ropes are
used in a handrail or
guardrail shall be strung
with maximum openings
of 3 ½ inches with
vertical supports 4 feet
Incorrect – opening
exceeds 3 ½ inches

Stairways with open
risers shall be
constructed to prevent
the through-passage of a
sphere with a diameter of
4 inches or larger
between any 2 adjacent
treads.
Design Standards
Handrails and guardrails must be designed
to withstand a 200 lb load applied in any
direction.
 Any glazing used must be safety glazing
 Exterior handrails and guardrails must be
made of metal, decay resistant or
pressure treated wood, or shall be
protected from the weather.

Handrails Forms



A common violation regarding
decks and stairs involves
handrail shapes.
Must be symmetrical at the
vertical centerline to allow for
equal wraparound of the
fingers and thumb.
Where the handrail is round
or truncated round cross
sectional gripping surface must
have a whole diameter of 2
inches.
2 inches
Continuity

Handrails must be continuous for the entire length of
the stairs except:
◦ At an intermediate landing
◦ A handrail may have newel posts
◦ At an intermediate wall provided
 the upper rail is returned to the wall or provided with a flared end,
 The horizontal offset between the 2 rails is no more than 12”
measured from the center of the rails, and
 Both upper and lower rails can be reached from the same tread
without taking a step.
Landings
An intermediate landing is required in any
stairs that has a height of 12 feet or
more.
 Intermediate landings connecting straight
stairs or stairs at a right angle must be as
wide as the stairs and measure at least 36
inches in the direction of travel.
 Curved or irregular landings shall have a
radius of at least 36 inches.

Landings
The level landing at the top and base of
every stairs shall be as wide as the stairs
and shall be at least 3 feet in the direction
of travel
 A landing is not required

◦ between the door and top of the interior
stairs if the door does not swing over the
stairs
◦ Between a sliding glass door and the top of an
exterior stairs of 3 or fewer risers
Landings

The exterior landing, platform or sidewalk
at an exterior doorway shall not exceed 8
inches below the interior floor elevation
and shall have at least 36 inches of surface
in the direction of travel
Ramp Landings
A level landing shall be provided at the
top, at the foot and at any change of
direction of the ramp.
 The landing must be at least as wide as
the ramp and shall measure at least 3 feet
in the direction of travel.

Ramps



Ramps shall not have a
slop greater than 1 in 8.
(One foot of rise for each
8 feet of run.)
Walkways with a slope of
less than 1 in 20 are not
considered ramps.
Ramps must have a slip
resistant surface.
Clearance
The clearance between the handrail and a
wall shall be at least 1 ½ inches.
 Handrails and their trim can project a
maximum of 4 ½ inches into the required
width of the stairs or landing.

Required Handrails



When the ramp has a gradient greater than 1 in 12
AND which overcomes a change in elevation of 24
inches or more, shall have a handrail on both sides.
Every ramp that overcomes a change of elevation of 8
inches or more shall have at least one handrail.
Handrails shall be located to the top of the handrail is at
least 30 inches but not more than 38 inches above the
ramp surface.
Openings in Handrails


The opening in a handrail shall
prevent the passage of a
sphere with a diameter of 4
inches or larger.
The triangular area formed by
the tread, riser or guardrail
shall have an opening that
prevents the passage of sphere
of 6 inches or more

This design is decorative but
openings exceed 4 inches.
This completes the section on stair, ramps and handrails
Federal Installation Standard
Each state must adopt a version that is at
least as stringent as the federal model
code.
 Each manufacture must provide 2 sets of
instructions

◦ At least 1 method for temporary support
when sited at the plant, retailer’s lot or home
site
◦ Instructions for the installation of the home
Federal Installation Standard
An installer must follow the temporary
set instruction until the home is placed
on its foundation
 Failure to support the home while stored
could result in structural damage

Federal Installation Standard
Variation to the installation instructions
by an installer is not permitted unless
permitted by the manufacturer, a
professional engineer or architect.
 Any alteration to the instructions must
not impose additional loads to the home
or its foundation

Federal Installation Standard

The installation standard applies to
manufactured homes only not
◦ Modular homes
◦ RV’s

A manufactured home is defined in
federal law as 8 body feet or more in
width or 40 body feet in length or when
erected is 320 or more square feet
(additional requirements can be found in
the definitions section of the code)
Federal Installation Standard

Before placing the home on the site
consider the impact of:
◦ Fire separation distances as may be required
by NFPA 501A and any local requirements
◦ The existence of flood plains
◦ Wind zone
◦ Roof load zone
◦ And the Thermal zone
Caps – this section is unique to WI*

Acceptable caps are*
◦ A combination of up to two-4” thick concrete blocks and not more than
one-2” hardwood lumber.
◦ Lumber must be at the top of the pier.
◦ A 4” block cannot be the bottom block in the pier but by be mixed with
other blocks
Caps
The cap must be the same width and
length as the top of the pier
 A two-piece cap shall be positioned with
the joint perpendicular to the frame

Federal Installation Standard

The location and spacing of piers depends
upon:
◦
◦
◦
◦
◦
◦

The dimensions of the home
Live and dead loads
Soil bearing capacity
I-Beam size
Footing size
Factors such as location of doors/windows
Unlike the WI Standard for Pre-2007 homes
the maximum spacing is 10 ft unless the
manufacturer provides for a greater distance
Federal Installation Standard
A single stack concrete pier load must
not exceed 8,000 lbs
 The concrete blocks must conform to
ASTM C-90


Prior to 2000, ASTM C90 included two different type designations for
concrete masonry units: Type I units were defined as moisture-controlled
units; Type II units were defined as non-moisture controlled units. All units
must still comply with the requirements for minimum compressive
strength, maximum water absorption, maximum variation in dimensions,
face shell thickness, web thickness, equivalent web thickness, and maximum
linear drying shrinkage exactly as they had before the removal of type
designations.
Pay special attention where a mating wall does not
support the ridge beam this is considered an
unsupported span
Where there is an open span that is greater than
10 ft, an intermediate pier is required 10 ft on
center despite the fact there is no direct support
above to the ridge beam
Piers can be off set up to 6” to clear plumbing,
electrical, mechanical, crawspaces or other devices
Federal Installation Standard
If outriggers or floor joists are used as an
alternative to perimeter supports, the
loan design must consider the additional
loads when sizing the pier and footings
 The end piers under the I-Beams may be
setback from the outside edge of the
home a maximum of 24” (This compares
to 36” in the Pre-2007 code.

This ends the Federal Installation Standard section
UDC Enforcement – SPS 320
The UDC is a minimum-maximum code
meaning that a municipality may not adopt
an ordinance on any subject within the
scope of the UDC including restrictions
on occupancy for any reason other than
noncompliance with the Code.
 A municipality cannot adopt that are less
stringent that the UDC
 Installation of manufactured home is a
part of the UDC.

UDC Enforcement



Is broader than just one and two family
dwellings, adult family homes providing care,
treatment and services for 3 or 4 unrelated
adults are also covered by the UDC.
Additions and alterations may be covered by
the code at the option of municipality
Determining if the code applies to an
addition or alternation is whether the
ordinance doing so was in effect at the time
of permit application or the beginning of the
project if no permit is required
UDC Enforcement
“Addition" means new construction
performed on a dwelling which increases
the outside dimensions of the dwelling.
 "Alteration" means an enhancement,
upgrading or substantial change or
modification other than an addition or
repair to a dwelling or to electrical,
plumbing, heating, ventilating, air
conditioning and other systems within a
dwelling.


"Approved" means an approval by the
department or its authorized
representative. (Approval is not to be
construed as an assumption of any legal
responsibility for the design or
construction of the dwelling or building
component.)
UDC Enforcement
Municipalities adopting the UDC must do
so in its entirety
 Where an existing building or
manufactured home is placed on a
different foundation, the new foundation
is consider an addition or alteration.

UDC Enforcement
In the case where a municipality does not
adopt the UDC, enforcement falls to the
Department of Safety & Professional
Services which may then contract for that
function
 If a municipality adopts an ordinance
while a permitted project is underway,
oversight then shifts to the municipality

UDC Enforcement
The UDC does not override local zoning
 The UDC does not apply to Indian
reservation land held in trust by the US
government

UDC Enforcement
Action to approve or deny a uniform building
permit application shall be completed within 10
business days of receipt of all forms, fees, plans
and documents required to process the
application, and completion of other local
prerequisite permitting requirements
 The sole reason for municipality or authorized
UDC inspection agency denying a building permit
application or the plans is that they do not
substantially conform to the provisions of the
code and other legal requirements

UDC Enforcement

Upon a finding of noncompliance with the
UDC, the municipality or inspection
agency must notify the permit applicant
and the owner.
This completes the UDC Enforcement section.
Understanding Soils

Soil type refers to
the different sizes of
mineral particles in a
particular sample.

Soil is made up of
finely ground rock
particles, grouped
according to size as
sand and silt in
addition to clay and
organic mater such
as decomposed plant
matter
Soils
The largest particles,
sand determine
aeration and drainage
characteristics of soil
 Clay’s tiniest submicroscopic particles
are chemically active
which binds with
water and plant
nutrients


The ratio of these
particle sizes
determines soil type:
◦ Clay
◦ Loam
◦ Clay-Loam

There are three soil
types
Soils

In testing a soil, try
to make a ball. If you
can roll a ball in your
hand the soil is clay
Soils

The Proctor compaction test is a
laboratory method of experimentally
determining the optimal moisture content
at which a given soil type will become
most dense and achieve its maximum dry
density.
Soils

The "Modified Proctor" test uses a 10 lb.
hammer falling through 18 inches, with 25
blows on each of five lifts (layers).
The compactive effort of
about 56,000 ft-lbf/ft³ is
achieved in the Modified
Proctor Test.
Soils






The original Proctor test uses a 4-inchdiameter.
The Proctor test gives two important
results: the maximum density of the soil and
the effects of moisture on soil density.
The most widely used field tests for field
compaction are:
1. Sand Cone Method (ASTM D-1556)
2. Drive Tube Method
3. Nuclear Method
Soils

Unlike the use of a pocket penetrometer,
The Proctor and Modified Proctor Tests
are conducted in the lab, not the field.
Soils
To compact clay soils a vibratory roller is
generally used. (Pictured below left)
 To compact clayey and silty soils, a
sheepsfoot roller is used mainly. (Pictured
below right)

Soils

Generally a contractor is given a
percentage of optimum compaction that
must be attained in the field. This is
referred to as the Relative Density or
R(%). Acceptable relative densities
generally range from 90 to 95% Part
3285.202 requires compaction to 90%.
Soils

Grading contractors usually limit the
depth of fill to 8” layers before
compaction.
Water and Frost
The volume of water expands a maximum
of 9% when frozen.
 Vertical loads caused by ice become a
problem when:

◦ they add to existing vertical loads
◦ act in a different direction
◦ act sequentially to aggravate the problem
Water and Frost
Water is unusual as a compound because
it expands when frozen
 Water is the only compound that can
cause frost heave in soil
 During frost heave, one or more soil-free
ice lenses grow, and their growth
displaces the soil above them

Water and Frost

Owing to the Gibbs-Thomson effect of
the confinement of liquids in pores, water
in soil can remain liquid at a temperature
that is below the bulk freezing point of
water. In fact, this leads to a decrease in
the freezing point / melting point that is
inversely proportional to the pore size
Water and Frost

Frost heaving requires:
◦ a frost-susceptible soil
◦ a continual supply of water
◦ freezing temperatures penetrating into the
soil

Therefore, remove the water even in a
frost-susceptible soil and there is no
heaving
Slides Completed

Please download the course exam at this
time. Send your completed exam to Julie
Patten call her at (608) 255-3131for
further directions.