Interpretation #8472

Published November 20, 2020

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Original Request

Code Version
2017
Code
RESIDENT
Code Description
Chapter
Chapter 4 Foundations
Section
R403.1.1, R403.1.6, R404.1.9
Topic
Manufactured Building (Modular home) foundation.

Question

Question # 1.) When using hollow isolated masonry piers foundation for a Modular home, does the foundation have to meet the same standards/requirements of the 2017 Florida Building Code (FBC) as for a conventionally built building?
Question # 2.) Can an engineer construct and the building official approve a foundation using the standards/requirements for a HUD/FDOT manufactured building (Mobile home) foundation i.e.; Rows of dry stacked hollow masonry piers with wood cap block, with soil anchors, and ignore the standards/requirements set forth in Chapter 4 of the 2017 FBC to be utilized as a foundation for a modular home?

Answer Published 11/20/2020 at 8:44 AM

1. Yes. Code does not have an exemption for modular homes. Section R101.2 provides the scope for the FBC-Residential.
2. Maybe. An engineer can design a foundation as long as the design meets all the loads specified loads. The provisions of the FBC-B are prescriptive and an engineer can deviate from them with engineering design. Large deviations from the FBC-R, particularly in stated loads, merit thorough investigation during plan review.

Commentary

For additional information regarding manufactured homes, please refer to FAC 15C-1 and 15C-2