HUD's regulations at § 203.43b of this chapter govern approval of real estate consisting of a one-family unit in a multifamily project, and an undivided interest in the common areas and facilities which serve the project, except where the project has a blanket mortgage insured under section 234(d) of the National Housing Act, 12 U.S.C. 1715y(d) (section 234(d)). Where the project has a blanket mortgage insured by HUD under section 234(d), this 24 CFR part 234 applies to the approval of a one-family unit in such project.