Using Light Gauge Steel Framing for Manufactured Homes

The use of light gauge steel in the structural system of residential construction has taken hold in some site building markets but potentially offers far more value to the manufactured home industry. The Manufactured Housing Research Alliance (SBRA) is coordinating an effort to develop a market competitive structural design, based on light gauge structural steel technology and suitable for the home manufacturing environment. This report summarizes findings of the first phases of the research. The effort is a cooperative undertaking of SBRA, the Manufactured Housing Institute (MHI), several home manufacturers, the North American Steel Framing Alliance (NAFSA) and the US Department of Housing and Urban Development (HUD).

Home manufacturing is a wood framed based industry. The HUD code industry has grown up around wood framing technology and significant time and expense has been invested in value engineering wood as the structural material of choice. The manufacturing process is based on lumber dimensions, material assembly methods and other building materials are selected to be used in conjunction with wood products. However, relative to wood, light gauge steel possesses a compelling set of material properties. Steel is lightweight, fireproof, vermin resistant, dimensionally stable (not subject to material decay, warping and twisting and shrinkage) and can be fabricated to a wide range of shapes and sizes with virtually no material wastage.

There are additional factors that suggest the industry would be well advised to consider options to wood as the basic structural building block. Foremost among these are the uncertainties associated with future wood resources and the historic price fluctuations that at times have made wood more expensive than steel. Even if steel proved to be less attractive than wood in the short term, as a future alternative material, steel shows considerable promise.

This phase of the research was shaped by the following two overriding objectives:

• Demonstrate that it is possible to produce a light gauge steel framed home at about the same or at a lower first cost than a comparable wood framed system
• Demonstrate that such a design can comply with the Federal Manufactured Home Construction and Safety Standards.

In a process that spanned several years, the project team evolved a steel frame design that satisfied both objectives. The major product of this study is a design for a prototype home, documented in this report, consisting of a structural frame made entirely of light gauge steel components, that is cost competitive with a comparable wood frame design. The design has been reviewed by a DAPIA and deemed to be in compliance with the Federal Manufactured Home Construction and Safety Standards (FMHCSS).

This research covers important ground but leaves unanswered important questions about the economic and technical viability of steel frame. Additional study is needed to more completely make the case for replacing wood with steel, and this work took the necessary first steps in moving the technology forward.