For as many types and varieties of manufactured homes as are now produced—with more to come—there are equally as many varieties of installation and support systems. This is the first guide to consider and compare the major foundation alternatives in use across the country. This guide was developed to fill this void with two goals in mind: to present a compilation of foundation ideas and inventions culled from experts and practitioners across the nation; and, to offer a range of practical and cost-competitive foundation solutions.

There is no single "best" foundation system. There is, however, a way to organize the process of deciding among alternative foundation designs that are appropriate for a given site and budget. The process starts with recognizing and prioritizing the major factors that influence the selection of the foundation system. Whether the main considerations are initial cost, frost heave resistance or a host of other issues, this information will help the reader focus on an appropriate foundation design. Understanding the foundation alternatives and proven design and installation practices is the next step. By presenting both sets of information, this guide helps narrow the field among many options and establish a methodical process for decision making.

Purpose of the Guide

Users of this guide should find practical and helpful solutions to their individual situations. Whether the reader is a retailer trying to find better and more economical ways to deliver a finished home, a contractor faced with an unusual soil condition, or anyone wanting to better understand the alternatives, suggestions can be found in this guide. There are summaries and tables for quickly identifying appropriate foundation systems for a particular site and homebuyer, as well as technical details for direct application to the project at hand.

A Source of First Resort for Foundation Systems Information

The guide is intended to be instrumental in fostering the wider dissemination of good ideas and "out of the box" thinking that characterizes the manufactured housing industry in general.

Some foundations use a combination of interior piers and perimeter walls to support the home.		Some foundations are recessed to create a "site-built" look.

Foundation Alternatives Rather Than a Single Best Solution

Each system included in this compilation suggest advantages in at least some settings. Comments about the pros and cons, as well as the special limitations of each system, are included.

When deciding among alternatives, several key conditions and objectives should be considered, such as: What is the budget? What kind of financing will be sought? What type of soil is found at the site? Is the area subject to frost? Is the home being placed in a land-lease community or on private land? Is the area subject to high winds, floods, or deep frost penetration? This guide explains how these factors influence the selection and design of a foundation, and makes suggestions and recommendations.

Information On All Types of Systems

The intent of this document is to be inclusive, offering guidance on an array of foundation systems. However, since there are many design variations, the guide only begins to sort through the options. The guide also suggests a way of organizing foundation systems into categories that are helpful in understanding almost any foundation design. Often the home manufacturer's installation instructions provide guidance on design and construction of foundation and support systems. While this document is intended to complement the manufacturer's guidelines, where there are discrepancies between the two documents the manufacturer's instructions should be followed.

A Wide Range of Designs

Ideas and examples of foundation designs were solicited from all parts of the manufactured housing industry. As a result, practitioners willing to share their ideas suggested many very practical and proven concepts. Experts, including licensed professional engineers and contractors, reviewed each system that was submitted. Some designs were eliminated because they were too specialized in their applicability. The designs that are included are worthy of consideration for many types of applications, sites and design objectives.

There are numerous ways homes are actually attached to their foundations.

HOW THE GUIDE IS ORGANIZED

The guide is organized into three sections as follows:

Factors to consider in foundation selection and design

This section discusses the major factors that drive the choice of a foundation system and the issues that influence the specific design of a foundation. The factors, listed below and discussed in detail, are used to rate the relative merits of foundation designs:

1. Site conditions
   
2. Major design factors
   
3. Best design practices
   

Non-proprietary systems, built of readily available materials

This section covers four foundation classifications:

• Pier and ground anchor support systems (the most popular method of securing manufactured homes to the ground)
  
• Crawl space systems
  
• Slabs-on-grade foundation systems
  
• Basements

A non-proprietary system is considered to be "in the public domain" — usable by anyone without paying a royalty, fee, or other consideration for its use. It is not a product of manufacturing or individual company output. Non-proprietary systems can be constructed by any qualified contractor, using materials available from most building suppliers.

Included in each foundation class are a series of case studies drawn from actual installations and contributed by practitioners from across the nation. The case studies suggest how a basic concept can be modified to meet the specific needs of a site, home design, or buyer preference.

Proprietary systems, wholly-owned by a single company

This section contains information about several proprietary foundation products marketed to the manufactured housing industry. A proprietary system is a product, manufactured by a company that owns some protectable interest in the design. Some are patented. There is spirited competition among manufacturers of these proprietary systems, resulting in rich choices for the retailer, builder, contractor and homebuyer.

The information contained in this section was prepared by the companies themselves. The following products and companies are represented:

• All Steel Foundation, Oliver Technologies, Inc.
  
• The Anchorpanel, Fast Track Foundation Systems
  
• Rigid Foundation Anchoring System, JM Products, Inc.
  
• The Storm Anchor System, The Anchor Post Company, LLC
  
• Vector Dynamics Foundation System, Tie Down Engineering
  
• Xi Foundation System, Tie Down Engineering