If the borrower neglects to offer security satisfactory to the board of directors within the time provided by the bylaws, his right to the loan shall be forfeited, and he may be charged with one month's interest, and all necessary expenses incurred, if any, in investigating and preparing the mortgage and note for his proposed loan. All mortgages given to the association shall be deemed conditional upon the performance of the provisions of this subchapter relating to the repayment of loans and interest thereon, and the bylaws of the association, although the same may not be fully expressed therein.