S.C. Code Ann. § 27-35-40

When a person enters upon or uses the premises of another without agreement or without the permission of the owner or by trespass the owner may at his option waive such tort and treat and deem such person a tenant at will. In such case the landlord shall have and be entitled to a reasonable rental for the use and occupation of such premises and all remedies for the enforcement of his rights in respect thereto as in other cases of tenancy at will.