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Manufactured Home Installation and Setup Terminology

Learning the lingo and terminology used in the manufactured home installation and setup process is the first step in understanding the process and ensuring that you get your home properly set up.

A  few common terms you should know:

Dealer Installers are employees or subcontractors of the dealership where you buy the home. In the US, manufactured home builders cannot sell a home themselves, there has to be a middleman or dealer.

Licensed Installer is an installer that is not a direct employee of a licensed dealer or builder. They must be licensed and bonded if state law requires it.

Stabilizing Devices are piers, footings, ties, anchoring equipment, anchoring assemblies, etc. that support and secure the manufactured home.

Manufactured home installation and setup

There are two main types of foundations, permanent and non-permanent.

Permanent Foundations

There are several types of foundations that a manufactured home can have. The permanency of the installation, chosen appearance, and the location of the home will determine which foundation is used.

If a homeowner owns the land and has no intention of moving the home again, a permanent foundation is usually the best. This kind of installation allows the homeowner the ability to retire the manufactured home’s title and get the property classified as real property.

The three main categories of permanent foundations are floating slab, roll-on, and pit-set. There’s also the basement and roll-on foundations.


Floating Slab Foundations

A floating slab foundation is a poured concrete pad with re-bar or J-bolts installed into the concrete so that the tie-downs can be attached to them instead of Helix Anchors.

The concrete floating slab foundation is usually only 6 inches thick but due to the way the concrete is formed and shaped the home can move along with the slab when the ground freezes, avoiding the possibility of cracking the foundation or damaging the home. There is a variable to the single floating slab foundation where two strips of concrete are used instead of one large slab.

Roll-on Foundation

Roll-on foundations are used when a homeowner wants the home to be even with the ground level. A deep foundation is dug out and reinforced walls are poured to so that the home looks as if it is sitting directly on the ground.

Manufactured home installation and setup - placing a manufactured home over a full basement

Pit-set Foundation

pit-set foundation is similar to a floating slab except the slab is poured one or two feet below ground level and walls are poured around the perimeter of the foundation to be even or slightly higher than the ground level. This creates a completely enclosed foundation.

Basement Foundation

Basement foundations are self-explanatory. A full or half basement is built under the home. This single wide is installed over a basement foundation.

Manufactured home installation and setup - single wide over a full basement foundation

Non-Permanent Foundations: Pads and Footings

For non-permanent foundations, there are two main choices, pads and footings.

A surface set pad foundation uses cinder blocks on level ground.

pier footing foundation system consists of several re-bar reinforced concrete columns that are poured to set directly under each pier or block set of the home. These columns may or may not meet the frost-line depth for that location.

The size of the foundation is determined by the soil bearing capacity and the size of the pad. Each state will have a minimum foundation pad size and will state what material the pad can be constructed with. For instance, Florida’s smallest pad size is 16”x16” and can be made of concrete or plastic, wood is not acceptable.

The size of the foundation determines the pier spacing and the amount of weight that each pad can carry. The manufacturer’s installation manual will provide additional information for proper pad sizes. Below is a footing pad diagram from a Skyline Homes manual:

Manufactured home installation and setup - footing pads for manufactured homes

Support Piers

Site built homes have stem walls on the outside, directly under the exterior walls. Manufactured homes have piers positioned under the chassis.

Piers are made of steel or concrete. There are three main support areas on a manufactured home: the frame or I-beam, the center-line, and the outside perimeter.

Perimeter piers must be centered under the I-beam and at the marriage line if the home is multi-section. The spacing of the piers must be carefully calculated by the installer. The block plan discussed earlier is used to determine this spacing.

There are various rules regarding the different piers. Clearance, pier height, single vs double stacked blocks, shims, and many more guidelines must be followed. The homeowner should research to know the specific rules for the home type and the location.

Blocking Plan

A blocking plan will be included with each home installation manual. It will be similar to the one below:

Single wide mobile home blocking plan

The illustrations below portray the various types of piers and footings that a manufactured home can have.

Manufactured home piers and footing installation x

 

Note: If a double interlocked pier is filled with concrete it can usually be used up to 80 inches in height.

Blocks under a new manufactured home w straps
Source: unknown

 

Steel pier and frost line footer:

Steel pier and frost line footings w text x

 

 

An illustration showing the difference between perimeter piers and center-line piers:

 

 

Perimeter and center line piers for manufactured homes

Anchors and Tie-Downs

Anchors, or tie-downs, are used to anchor the home’s frame to the earth or the foundation.

Improper anchoring or tying-down a home is the main reason we see so many homes on their sides on the weather channel. It is not the home itself but the lack of tie-downs or anchoring system used on the home.

If a new manufactured home is correctly tied down it can withstand over 110 mph winds.

Screen shot at a m
Source Unknown

Types of Anchors and Tie-Downs

Ground Anchor – any device approved by the DMV that is used for the purpose of securing a manufactured home to the ground in order to resist wind forces. Ground anchors are rated by working load, which is the maximum load for design purposes. The ultimate load is the working or design load multiplied by the safety factor of 1.5.

Frame Tie or Tie Down – any device or method approved by the department and used for the purpose of securing the mobile/manufactured home or park trailer to ground anchors in order to resist lateral wind forces.

Underbelly and blocks under a new manufactured home with tie downs
Source: Unknown

Vertical Tie – any device or method approved by the department and used for the purpose of securing the mobile/manufactured home or park trailer to ground anchors in order to resist vertical or uplift forces caused by the wind.

Over-Roof Tie – any device approved by the mobile/manufactured home manufacturer or listed by the DMV to be used for the purpose of securing the manufactured home to ground anchors in order to resist wind forces. Ties may be installed over metal roofs.

 

Waynes mobile home service
Source: Wayne’s Mobile Home Service