No agreement, that a building erected with the consent of the landowner by one not the owner of the land upon which it is erected shall be and remain personal property, shall be effectual against any person, except the owner of such land, his heirs, devisees and persons having actual notice thereof, unless such agreement is in writing and signed by such landowner or by someone duly authorized for that purpose, and acknowledged and recorded as deeds are required to be acknowledged and recorded under this chapter. This section shall not apply to agreements entered into prior to the 28th day of April, 1903, and then outstanding.