OMHC Approval of ABS (Pier) Pads

On April 20, 2011, the Ohio Manufactured Homes Commission (OMHC) held a hearing on proposed changes to Ohio Rule 4781, which governs installation of manufactured homes in Ohio. One change to those rules was to allow ABS pads as footings for manufactured homes. The exact wording is as follows:

"ABS footing pads shall be permitted if used in accordance with the manufacturer installation instructions and/or specification sheet of the specific ABS pad being used. The use of ABS pads must be used in conjunction with solid perimeter skirting in accordance with paragraphs (D) (1) to (D) (4) and (E)(1) to (E)(6) of rule 4781-6-02.5 of the Administrative Code."

We attended this hearing specifically to voice concerns about this revision to the previous rules that did not allow these pads. Three ABS pad manufacturers, Oliver, Polyvulc, and Tie-Down Engineering, also spoke at the hearing in favor of the changed rules. Our assessment of the attitude of the OMHC during the hearing was that it favored the rule change. Therefore, we wrote the letter attached to this blog post and submitted it to the OMHC within the comment period (less than 24 hours). That letter is included here:

OMHC Has Approved ABS Pads For Manufactured Homes


We found later that the OMHC had indeed passed the rule change, allowing ABS pads.
As the letter states, we are concerned that ABS pads will be used in conditions where they are not intended. Although the rule change states that the installer must follow the manufacturer's installation instructions, we had reviewed the instructions of the three main pad manufacturers and found them greatly lacking in detail, and where there is a lack of detail, there is opportunity for misuse. In a conversation with two of the manufacturer's representatives after the hearing, we were informed that other states that have allowed ABS pads also have training sessions particularly for ABS pads. Our feeling is that if ABS pads are allowed, they need to have such required training additional to following the manufacturer's instructions.

Essentially, our concern is that ABS pads require that soil be used as a replacement for concrete footings or slab. Granted, some soils can be "hard as concrete" when at certain moisture content and without organic matter and voids. That is to say, the soil has the same bearing capacity as concrete. However, unlike concrete, which has a bearing capacity that changes little over a wide range of conditions, the bearing capacity of soil can change dramatically.

Therefore, if soil is going to be used to replace concrete, the soil conditions must be controlled. In the one decently documented case where ABS pads were successfully used, soil moisture and frost heave were well-controlled. In this case, insulated skirting to maintain temperatures above freezing in the crawlspace and drainage around the home's perimeter were used. The manufacturers' installation instructions usually state a minimum required soil bearing capacity and that the pads be placed "at or below the frost-line". The insulated skirting, moves the frost line to grade. The required soil bearing capacity is in part essentially a requirement for proper drainage because the soil bearing capacity can drop significantly as the soil moisture increases. Thus, soil moisture needs to be controlled through proper drainage.

But, can installers be trusted to measure soil bearing capacity accurately or to accurately calculate whether an ABS pad be able to take the weight put on it? Can most inspectors be trusted to check the right parameters and review the required information. The OMHC has left those questions wide open. Currently, installers and inspectors are not required to have special training. Therefore, no two installers will be doing the same installation or checking the same parameters. That is why we wrote the letter to the OMHC. If ABS pads are going to be used, they need to be used properly and uniformly. They cannot simply be used in place of concrete footings because soil is not exactly the same as concrete and the weight being put on the soil will usually be more for ABS pads than for concrete footings.

We are going to continue pursuing the issues of proper training for ABS pad use. We are also aiming for the requirement that a licensed engineer approve the use of ABS pads to assure that homeowners get the home that they believe they are buying. In a future blog, we plan on commenting research sponsored by the Ohio Manufactured Home Association which has been used to back the approval of the pads. Stay tuned.