Water damage and flooding of manufactured homes

Manufactured Structures Bulletin 27

To:

Minnesota Building Officials, MMHA, A.P.A.C., Dealers and Installers

From:

Thomas R. Joachim
State Building Official

Date:

April 1997

Subject:

Water damage/Flooding of Manufactured Homes

Due to flooding in many areas of Minnesota, the Minnesota Building Codes and Standards Division encourages municipalities that have manufactured home communities or manufactured homes installed on private property within their jurisdiction to notify the manufactured home residents and park managers of possible hazards caused by flooding.

The three types of pressures caused by flooding are hydrostatic, hydrodynamic, and debris impact. Some of the damages that may occur to a manufactured home from the pressures;

Lateral displacement of walls and floors.
Cracking of wall finishes.
Saturation of soils may cause footings to become unstable and fail.
Flotation may cause support system to become unstable or anchoring system to fail.

t also stated in a Federal Emergency Management Agency (FEMA) Report from 1985 that a two foot depth of flood water on a manufactured home may result in damages up to about 80% of the value of the manufactured home. This would include items of non-structural nature not previously mentioned. Some of the non-structural items affected by flood waters would be;

Floor and Wall Insulation
Siding and Sheathing
Mechanical duct work located in the belly area of the home
Gas line connections in and under the home
Plumbing systems connections or drain/waste slope
Electrical connections under home (receptacle from heat tape, and electrical in floor and walls)
Furnace
Water Heater

Municipalities should inform manufactured home residents which have had their manufactured homes in flood areas of the following:

Have gas line system retested for leakage in accordance with MSBC 1350.3400 subp. 4.
Remove skirting around home to allow drying.
Have a Registered Installer check soils around footings for washout or scouring, check shims and piers for stability, check anchors (if installed) for stability from withdrawal.
Check drain/waste lines for proper slope and leaks.
Remove bottom board (belly paper) to allow drying of insulation, decking, structural lumber. If necessary replace insulation and belly paper with materials of like kind for compliance to MSBC 1350.3800.
Loosen siding or sheathing to allow for drying of construction materials and insulation in order to avoid decay and bacterial growth.
Check for water in ductwork and remove.
Have an electrical contractor check all affected electrical system items for damage.
Check and clean water lines.
Check Furnace.
Check Water Heater.

The items listed are not required and are meant as examples of items to be checked for protection of the homeowners and the value of their manufactured homes. In some cases if water did not touch the bottom of the manufactured home proper only footings, piers, and anchors may require inspection for damages.