No lien or encumbrance upon the land created before the work was commenced or materials furnished shall operate upon the building or structure erected thereon, or materials furnished for and used in the same, until the lien in favor of the person doing the work or furnishing the materials shall have been satisfied; nor shall any lien or encumbrance upon the land created after the work was commenced or materials furnished operate on the land, or such building or structure, until the lien in favor of the person doing the work or furnishing the materials shall have been satisfied. Unless otherwise provided in the subordination agreement, if the holder of the prior recorded lien of a purchase money deed of trust subordinates to the lien of a construction money deed of trust, such subordination shall be limited to the construction money deed of trust and said prior lien shall not be subordinate to mechanics’ and materialmen’s liens to the extent of the value of the land by virtue of such agreement. In the enforcement of the liens acquired under the previous sections of this chapter, any lien or encumbrance created on the land before the work was commenced or materials furnished shall be preferred in the distribution of the proceeds of sale only to the extent of the value of the land estimated, exclusive of the buildings or structures, at the time of sale, and the residue of the proceeds of sale shall be applied to the satisfaction of the liens provided for in the previous sections of this chapter. Provided that liens filed for performing labor or furnishing materials for the repair or improvement of any building or structure shall be subject to any encumbrance against such land and building or structure of record prior to the commencement of the improvements or repairs or the furnishing of materials or supplies therefor. Nothing contained in the foregoing proviso shall apply to liens that may be filed for the construction or removal of any building or structure. Notwithstanding the provisions of subsection C of § 43-3, a general contractor may, prior to or after providing any labor, services, or materials, contract to subordinate his lien rights to prior recorded and later recorded deeds of trust, provided that such contract is (i) in writing and (ii) signed by any general contractor whose lien rights are subordinated pursuant to such contract.