Hurricane

Foundation Qualification Requirements

Ineligible Foundations

Homes on a foundation constructed of unrestrained stacked masonry or stone (a drystack foundation) are not eligible for any FORTIFIED designation. Note: Ineligible foundations may be retrofitted in accordance with a professional engineering plan and must comply with Section 1.2.3.2 (below) to be considered eligible.

All Elevated-Floor Home-to-Foundation Connections

To be eligible for designation or re-designation under the FORTIFIED program, homes with elevated floors (not slab-on-grade construction) must have adequate positive connections from the floor or wall structure to the supporting foundation. For example, homes on piers or pilings must have connections from the tops of the piers/pilings to the home’s floor beams and a home on piers with shallow foundations must have connections that provide a continuous load path to the foundations. All connectors must be free from damage, corrosion-resistant (if applicable) in accordance with Appendix D of this standard, and installed per the connector manufacturer’s installation instructions.

All Elevated-Floor Home-to-Foundation Connections

Foundations must be capable of resisting the design wind load requirements with no more than ¼-in. lateral deflection. Requirements specified in the US Department of Housing and Urban Development (HUD) Permanent Foundation Guide for Manufactured Housing (HUD4930.3G) dated September 1996 or later provide useful assistance in identifying suitable foundation options. Based on results of past inspections of home installations that were reported as permanent, the following requirements of the HUD Guide and FORTIFIED requirements are emphasized and are part of the Field Evaluation inspection.

• Screw-in soil anchors are not considered a permanent anchorage and cannot be used as any part of the required permanent foundation unless their heads are restrained from lateral movement by embedment in a reinforced concrete footing or concrete slab.
• All concrete masonry unit (CMU) bearing walls, piers, and columns, as well as any units used as part of systems to resist uplift, overturning, and lateral loads must be composed of reinforced concrete masonry with mortared bed and head joints. Cells with reinforcing must be fully grouted. Dry-stacking of CMU is not allowed.
• All bearing walls, piers, and columns must be installed on and connected to acceptable footings or a concrete slab. Footings and slabs must be protected from the effects of frost heave by extending below the frost line or by using a frost-protected shallow foundation design.
• Walls and piers used as part of the uplift, overturning, or lateral load–resisting system must include adequately sized connections and elements capable of resisting tension or compression loads as appropriate. Straps or cables are acceptable, provided they are connected to the home or its chassis and transfer the design loads to the slab or footings supporting the walls, piers, or columns. Use of frictional resistance between the home or its chassis and the tops of the walls, piers, or columns or between the bottom of the walls, piers, or columns and the footings to resist lateral loads is not allowed.