" beijing city estate makes over administrative measure " the 34th is made " open to booking commodity house , ought to according to cover inside floor area valuation " mandatory regulation , when signing commodity house to open to booking a contract consequently , the person that buy a house and development business can choose only according to set inside floor area computation ; and buy blame goods the residence , villatic or it is ok to buy those who show a house to buy room person to remain the same in floor area , set inside the floor area , proper motion in pressing a means of 3 kinds of valuation chooses a kind of means and development business to undertake conventional , also can agree by its other places such as usable floor area type undertakes valuation 《北京市城市房地产转让治理办法》第34条做出了“预售商品住宅的，应当按照套内建筑面积计价”的强制性规定，因而签订商品住宅预售合同时，购房人和开发商只能选择按照套内建筑面积计算；而购买非商品住宅、别墅或购买现房的购房人仍然可以在建筑面积、套内建筑面积、按套三种计价方式中自行选择一种方式和开发商进行约定，也可以约定按使用面积等其他方式进行计价。
