Opinion,
Me. Justice Mitchell’:The regulation of party-walls is a very ancient form of exercise of the police power, and came to Pennsylvania from the customs of London, like so many other parts of our early law. Those interested will find the subject discussed in a note to Bloch v. Isham, 7 Amer. L. Reg., N. S., 10. But such regulation, as it exists in this and most others states, is an interference with the rights and enjoyment of property, sustainable only on the police power, and therefore to be governed and measured by the strict extent of the statutory grant. «
The plaintiff’s right to recover in this action, therefore, must clearly appear in the provisions of the act of April 8, 1872, P. L. 986. Section 5 of that act, providing for tearing down and replacing an existing party-wall, which is unsuited for a new building about to be erected, is the one under authority of which plaintiff proceeded; but that section does not determine when contribution from the adjoining owner shall be due, and to ascertain this we must turn to § 4, which provides that the adjoining owner “ shall not use said party-wall by building into or against it, or by in any way using it for any new building or structure, until he shall have paid,” etc. This provides for two contingencies : First, a new wall where none was before, which cannot be used at all till payment; and, secondly, a new wall replacing an old one, of which no new use can be made without paying. If the old wall is sufficient for the old use, and the new one is built solely to accommodate a new use, the adjoining owner who merely continues the old use cannot be called upon to contribute for his neighbor’s improvement. The statute does not make him in any way liable to pay until he be*637gins himself to make a new use of the new wall, and his liability even then is for his proportion of, so much of the wall only as he uses. Thus, if the wall is one hundred feet high, as modern buildings not unfr,equently are, and the adjoining owner only desires to use forty feet of it, he is only liable for four tenths of one half the cost of the wall, and he cannot be called upon to pay that till he begins to make actual use of it. This is the plain language of the statute, and it is the fair and just rule. It is, moreover, in accordance with the construction always given to the act of 1721,* regulating party-walls in Philadelphia, and thus keeps the laws in the two great cities of the commonwealth in harmony.
The replacing of defendant’s beams and supporting them in the new wall, in the same manner and to the same extent that they had been supported in the old, was not a new use, but a continuance of the old. The only change made was for plaintiff’s benefit, and at his instance.
There is nothing in the testimony about the change in the plan and size of the wall upon defendant’s request, to call for a different rule in this case. The change was of no present advantage to defendant, nor did he make any promise to pay at an earlier day than the law fixed. It was a mere suggestion on his part, looking to the probable future use of the wall; and it was apparently accepted by the plaintiff and- the building inspector as wise and proper, in view of such future use. There was nothing in it to vary the present legal position of the parties. Both of defendant’s points should have been affirmed.
Judgment reversed.
Act of February 24, 1721, 1 Sm. L. 125.