The provisions of § 31-53 shall apply to the construction or rehabilitation of homes by an eligible developer under this part, whenever the eligible developer either (1) obtains a mortgage loan from the state for the construction or rehabilitation of ten or more houses or (2) enters into contracts or agreements with ten or more individual recipients of mortgage loans from the state within any six-month period to build houses for them on land or lots which are a part of a single common land development. The provisions of said section shall not be applicable to any type of builder engaged in the construction of a single home for a single mortgagor, except for a housing authority and except as provided above, or to any builder not engaged in the construction of homes under the provisions of this chapter.