Leviticus 27:13-15

13And if they will in any wise redeem it, then they shall add a fifth [part] thereof unto thy valuation.

14And when any one halloweth his house, that it may be holy to Jehovah, the priest shall value it, [judging] between good and bad: as the priest shall value it, so shall it stand.

15And if he that halloweth it will redeem his house, he shall add the fifth of the money of thy valuation unto it, and it shall be his.