Foundation Requirements

The following table lists each foundation component and any related requirements for “proposed or under construction” cases.

Foundation Component

Requirement

Piers and Footings

The load-bearing piers and footings must

·   be of sufficient size and number to distribute the weight of the manufactured home evenly

·   be of materials acceptable to the building authority having jurisdiction, and

·   (where applicable) have footings which extend below the frost line.

Concrete Slabs or Continuous Footings

·   Concrete slabs or continuous footings are acceptable in areas where their use is permitted by local building authorities.  Steel anchorage devices must be cast into the concrete slab or footing and be capable of providing holding strength to resist horizontal and uplift forces.

Anchoring Devices

Anchoring devices, adequate to resist all loads, must

·   be attached to the main frame of the unit by a bolted, welded, or mechanical connector

·   be placed at every supporting pier or as specified by the manufacturer, and

·   extend into the pier footing. 

Anchoring straps or cables affixed to ground anchors, other than pier footings, will not meet this requirement unless specifically allowed by the building authority of jurisdiction.

Hurricane Ties

Properties located in Wind Zone II or III (wind speeds in excess of 80 mph) must be provided with diagonal hurricane ties which have been properly engineered for the location, and comply with the requirements of the building authority having jurisdiction.

Important:  The installation procedures included in both the manufacturer's foundation instructions and NCS BCS Handbook A225.1 are not generally adequate for manufactured homes in these areas.