Manufactured Home Requirements

 

Manufactured (Mobile) Home Installation

44 CFR 59.1 Definition: “Manufactured home” means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities.  The term “manufactured home” does not include a “recreational vehicle”.

A manufactured home includes a building that is transportable, a mobile home or a “double wide” under the NFIP regulations.

See FEMA’s Manufactured Home Installation in Flood Hazard Areas, FEMA-85, for additional guidance.

 

Manufactured Homes in Special Flood Hazard Areas (A Zones)

 

  1. For a manufactured home outside of an existing manufactured home park or subdivision, the requirements are the same as for site-built homes. Manufactured homes must be anchored to a permanent foundation.
  2. Within an existing manufactured home park or subdivision the community has the option of either requiring the home to be elevated at or above the BFE; or have the home elevated on reinforced concrete piers, blocks, etc., to at least 36 inches above grade.
  3. In the event of substantial damage (over 50 percent of pre-damage value), a replacement manufactured home must be elevated to or above the BFE.
  4. If a pre-FIRM (Flood Insurance Rate Map) manufactured home is moved at the onset of a flood event and moved back after the water recedes, it may be replaced at the same elevation.  NOTE: The manufactured home must be the same home that was previously moved and placed in the original building footprint.

 

Elevation

Generally, manufactured homes must meet the same flood protection requirement as “stick built” or conventional housing.  Since they are usually residential buildings, they must be elevated so the lowest floor is above the Base Flood Elevation (BFE).

General elevation and foundation requirements –

(1) Methods and practices.  Manufactured homes located wholly or partly within special flood hazard areas must be installed on foundations engineered to incorporate methods and practices that minimize flood damage during the base flood, in accordance with the requirements of the LAHJ, 44 CFR 60.3(a) through (e), and other provisions of 44 CFR referenced by those paragraphs.

(2) Outside appliances.

(i) Appliances installed on the manufactured home site in flood hazard areas must be anchored and elevated to or above the same elevation as the lowest elevation of the lowest floor of the home.

(ii) Appliance air inlets and exhausts in flood hazard areas must be located at or above the same elevation as the lowest elevation of the lowest floor of the home.

44 CFR 59.1 Definition: “Manufactured home park or subdivision” means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale.

44 CFR Section 60.3(c)(12) allows for a limited exemption to elevating to the BFE in pre-FIRM manufactured housing (mobile home) parks.  In such older parks, a newly placed manufactured home chassis may be elevated only three feet above grade provided it “is supported by reinforced piers or other foundation elements of at least equivalent strength.” This exemption does not apply to new manufactured housing (mobile home) parks, expansions to existing parks, to manufactured housing located outside a pre-FIRM park, or to repairing or replacing a manufactured home in a pre-FIRM park substantially damaged by a flood.

This exemption is a compromise that tries to balance the flood hazard against the severe economic impacts on some manufactured home park owners that would result if elevation to the BFE were required.  The exemption may not be necessary or appropriate for your community, especially if manufactured homeparks are able to meet the requirement to elevate to the BFE.  In other areas, the flood hazard may be so severe that the exemption may put lives and property at too great a risk.  Many states have not included this exemption in their model ordinances and it may not be in your regulations.

 

Anchoring

44 CFR  60.3(c)(6)  …[Manufactured  homes  must]  be  elevated  on  a  permanent foundation … and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.

A “permanent foundation” means more than a stack of concrete blocks.  It should include a below-grade footing capable of resisting overturning, the depth needs to account for frost depth and expected scour, the footing must be sized appropriately for the site’s soil bearing capacity, and the design needs to account for seismic and other hazards.

The following types of permanent foundations should be used:

  • ¨ Reinforced piers
  • ¨ Posts
  • ¨ Piles
  • ¨ Poured concrete walls
  • ¨ Reinforced block walls, or
  • ¨ Compacted fill

“Adequately anchored” means a system of ties, anchors and anchoring equipment that will withstand flood and wind forces.  The system must work in saturated soil conditions.  Usually this means over-the-top or frame tie-downs in addition to standard connections to the foundation.

Most states have manufactured home tie-down regulations.  Check with your state NFIP coordinator to see if your state’s regulations also meet the NFIP anchoring standard.  If so, you need only make sure that the state requirement is met for each new manufactured home installed in your floodplain.

See FEMA’s Manufactured Home Installation in Flood Hazard Areas, FEMA-85, for additional guidance.

The anchoring requirement does apply in an existing (pre-FIRM) manufactured housing or mobile home park.  Even if not elevated above the BFE, the owner must still certify that the anchoring system will still withstand the forces of a flood over the first floor.

 

Evacuation

In some areas, there is adequate warning time to remove a manufactured home from harm’s way.  Protecting such property should not be discouraged, so FEMA allows an evacuated manufactured home to be put back on the original site without having to meet the requirements for siting a new building.  An existing manufactured home can be returned after an evacuation without being elevated provided it is not enlarged or altered.

 

Recreational Vehicles

44 CFR 59.1 Definition: “Recreational vehicle” means a vehicle which is: (a) built on a single chassis; (b) 400 square feet or less when measured at the largest horizontal projection; (c) designed to be self-propelled or permanently towable by a light duty truck; and (d) designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

A recreational vehicle placed on a site in an SFHA must: ¨

  • Meet the elevation and anchoring requirements for manufactured homes,
  • Be on the site for fewer than 180 consecutive days, OR
  • Be fully licensed and ready for highway use.  “Ready for highway use” means that it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and has no permanently attached additions.

The purpose of this requirement is to prevent recreational vehicles from being permanently placed in the floodplain unless they are as well protected from flooding as a manufactured home.

 

 

 

 

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