通外面的门应该买铁皮门(steel entry door),home depot大概不到$200. 量好尺寸,不用换门框。
http://www.homedepot.com/Doors-Windows-Entry-Doors/h_d1/N-5yc1vZbuhp/R-202036412/h_d2/ProductDisplay?catalogId=10053&langId=-1&storeId=10051#.UNM4L-Ri684