Modular Housing refers to structures constructed according to state and local codes off-site in a factory, transported to a building lot, and assembled by a contractor into a finished house. Although quality can vary, all of the materials – from framing, roofing and plumbing to cabinetry, interior finish and electrical – are identical to what is found in comparable quality conventional “stick-built” housing.
The Appraiser must treat modular housing the same as stick-built housing, including reporting the appraisal on the same form. The Appraiser must select and analyze appropriate comparable sales, which may include conventionally built housing, modular housing or manufactured housing.
For additional information see Handbook 4000.1 II.D.3.c.vii.D at https://www.hud.gov/program_offices/administration/hudclips/handbooks/hsgh