I have had several professional installers reach out to me lately regarding some recently issued addendums (documents or designs) to the manufacturer’s installation manuals. So, I thought we should talk about these addendums to help installers take advantage of these alternative approaches to the installation, and possibly sound a warning on some steps that might be overlooked.
Should you receive any designs or documents from the manufacturer (or any other source) that are not a part of the installation manual that was shipped with the home, I suggest you consider the following:
These addendums, designs, or documents MUST be stamped by the manufacturers DAPIA (design approval primary inspection agency), and the particular manufacturer must be identifiable on the documents. Without these elements, these documents should not be used. Remember, only use DAPIA approved designs!!!
Even with the DAPIA stamps and the manufacturers identification on these addendums, it is important to be certain that they are current. DAPIA approvals are always changing to keep pace with changing construction structure methods and evolving building codes. If you are hanging onto details and designs that are more than a few years old, double check with the manufacturers Quality Assurance Manager to be determine if the documents that you are using are current.
Read the fine print! Take the time to read and re-read every note on any addendum you use and be prepared to defend every step you have taken. There are often limitations that may restrict the use of certain designs. For example, many foundation addendums require a minimum soil bearing capacity of 2,000 PFS, so be certain you haven’t overlooked such limits to these addendums.
Obtain all needed support documents! For example, if the addendum is limited for use on non-frost susceptible soils, you will need to have documents in your installation file to show the soil meets these requirements. Maybe you are using designs that require you to determine the “air-freeze index, so you’ll need to gather this information before construction begins!
Don’t forget the local building code official! Most addendums require acceptance by the local authority having jurisdiction (AKA code official), so discuss the addendum with him/her during the building permit application process. Get his approval in writing (if possible). Keep in mind, you are the primary source of information for the code official. Make certain that you are both on the same page before the construction starts!
Finally, as we have talked about in the past, you are required to maintain records of every home you install for at least 3 years. Be certain to keep copies of these addendums along with your other records.