Why Don’t Engineers Agree on Permanent Foundations for Manufactured Homes?

Written By: Paul Hayman, P.E.

It would seem that if any group of people would tend to agree on something, it would be engineers. But on the subject of permanent foundations for manufactured housing, you will rarely find two engineers in complete agreement as to what is required. Why is that?

The simple answer is that the source document, the September 1996 Permanent Foundations Guide to Manufactured Housing, is not clear. It is an inch thick document that spends about half a page defining permanent foundations in very general terms and then the rest of the document gives examples of foundations guaranteed to meet the manuals requirements (except for one which was removed after the authors decided it didn’tmeet requirements—even the authors can’t agree). The problem is that these example foundations, although elegant from an engineering perspective, are extremely expensive and can add thousands of dollars to set up requirements for which the buyer receives nothing.

As a result, the sample foundation designs are largely ignored and the most cited portions of the manual are the first page, which permits engineers to design alternative foundations from scratch, and the paragraph on existing construction, which states only the anchorage and footings on existing foundation need meet the “intent” [their word] of the new foundation requirements. Who defines intent? The engineer does. This turns the entire certification process for existing homes a matter of subjective interpretation. HUD has done little to help clarify the confusion as the manual has not been revised since its original publication in 1996. The pending HUD Model Installation Standards, due to go into effect sometime this year (but nobody knows when), may supersede the PFGMH, but for the foreseeable future, the confusion remains.

For now, the questions of interpretation remain unanswered by HUD in any official capacity. When I first began specializing in manufactured home foundations and I couldn’t get an official (i.e., written by a HUD engineer in an official capacity) response to my questions on interpretation, I sent a certified letter to every regional HUD office in the country.

In the letter, I outlined my interpretation of the requirements and asked that if they disagreed with me to please let me know. I received a phone call from an engineer in the Missouri HUD office. He was no longer acting in an engineering capacity, but he told me verbally that he agreed with my interpretation. However, he told me I would receive no written responses from any HUD regional office. He was right.

The confusing questions remain unanswered. Does the HUD manual require block/brick stem walls with frost line footings? No, but many will tell you yes. Does the HUD manual require tie downs to be anchored in concrete? Yes on vertical tie downs, no on lateral tie downs, but most will interpret it as yes on all tie downs. Are frost line depth footing protection required? Maybe. It depends on location and design. Do piers need to be mortared together? No, but many will tell you yes. Can bonding cement be used to upgrade dry stacked piers? Yes, but only if the bonding cement is used according to the manufacturer’s requirements which are not met by any manufactured home in the nation, so the real answer is no. Can architects sign off on manufactured home foundations? Yes, but some HUD offices will tell you no.

So what is a lender to do? Find an engineer who is thoroughly knowledgeable with the PFGMH. He can save your borrower a lot of money.

About the Writer. Paul Hayman, P.E., is owner of Hayman Residential Engineering Services, Inc. His company specializes in providing engineering certificates in 49 states. He can be reached at hresanswers@hayman-res.com or www.hayman-res.com.

SOURCE: Published by NAMP Publishing Group, a division of the National Association of Mortgage Processors (http://www.MortgageProcessor.org)