Existing versus New Foundations on Manufactured Housing?

On December 14th, 2009, posted in: Residential by

| Tags: , , , ,

There is a very important issue that many lenders and even some engineers don’t recognize, and that is the issue of new construction versus existing construction when evaluating foundations on manufactured homes. Do existing manufactured homes have to meet the same foundation requirements as new construction? The short answer is no!

The required HUD manual is the September 1996 Permanent Foundations Guide to Manufactured Homes which is a design manual for foundations on manufactured homes. The manual was intended to give specifications for foundations on new construction. However, engineers are required to certify compliance with this manual for existing construction. So what standard do they use? Many engineers will require that existing construction meet the same requirements as new construction, but that is not what the manual states.

The only reference to existing construction is a short two sentence paragraph (paragraph 101-2) that states: “The practices recommended in the Handbook are not intended to be applied retroactively to existing sites unless the authority in the jurisdiction considers such application essential for safety and health of occupants. Upgrade of existing anchorages and footings shall meet the intent of the definition of permanent foundation stated herein.”

Let’s look at what this means.

The practices recommended in the Handbook are not intended to be applied retroactively to existing sites

. . . This statement explicitly states that existing construction should not be held to the same standard as new construction.

. . . unless the authority in the jurisdiction considers such application essential for safety and health of occupants. (I am not aware of any authority anywhere in the US that has mandated the PGFMH standards for safety and/or health reasons.)

Upgrade of existing anchorages and footings shall meet the intent of the definition of permanent foundation stated herein. Here is the sentence that causes so much confusion. First, existing foundations only need meet the “intent” of the standards.

Who decides what constitutes “intent?” The engineer does! This is why it is hard to find two engineers who will agree on what an existing foundation needs to be HUD compliant.

Second, that sentence states that “anchorages and footings” shall meet the engineer’s definition of intent. What about the skirting wall and piers? Are they exempt from consideration on existing foundations? Does the engineer have to address only the anchorage and footing and nothing else? Again, it will depend on the engineer.

I have seen engineers run the entire spectrum from “grandfathering” any existing foundation, which is clearly unwarranted, to requiring the letter of the new construction standards, which is also clearly unwarranted.

The “intent” of the anchorage is to adequately tie the home down during expected wind and seismic events. The“intent” of the footing is to adequately support the weight of the home given soil load bearing conditions and frost depth requirements. It is important to choose an engineer who is very knowledgeable about the PFGMH standards. An engineer who is inexperienced in these standards could wind up costing your borrowers thousands of dollars in unnecessary upgrades.

Share
No Responses to “Existing versus New Foundations on Manufactured Housing?”

Leave a Reply

You must be logged in to post a comment.