就違章建築之法律性質而言。從「法秩序一致性」原則及「違法性一致性」觀點論證,違章建築不論在行政法上或者民法上都具有違法性,違章建築是未經登記的違法建築,它是「具有違法性的工作物」,是一種性質上為「四分之三禁制物」之不應融通物。根本不應該再成為交易之客體。第二、就違章建築之法律地位而言。實務上創設違章建築具備之「事實上處分權」,性質上只是一種權宜的「殘缺所有權」或「不完整權利」,不應再考慮賦予具有完整物權地位之權利。違章建築之興建,不僅欠缺習慣法所應該具備之「共同體意思說」(被闡明的共同體普遍意思),也違反強行規定及公序良俗,更不符合法官認定與宣示其為習慣法之可能,亦無許其得適用或類推適用民法第767 條規定行使物上請求權之餘地。
Regarding the legal nature of the illegal building, if we justify from the principle of "legal order consistency" and the point of view of "consistency of illegality," the illegal constructions are illegal no matter in administrative law or civil law. Illegal buildings are unregistered constructions, it is "three-fourths of a ban" in nature. It should not be the object of the civil transaction. Relating to the legal status of illegal constructions, the "the right of disposition de fecto" created by of the supreme court in Taiwan is only an temporary "incomplete title" or "incomplete right of prosession" and should no longer be given the right of property or ownership. The construction of illegal buildings lacks not only the "common meaning" of the customary law, but also violates the provisions of the law and public order. It gains no possibility for the court to find and declare it as a customary law. It should not be allowed to apply or by analogy the provisions of Article 767 of the Civil Code, and to exercise the right of claim (rei vindicatio) as well.