delivered the opinion of the court
Long and Furst leased to Curtin nine acres of land on which stood a furnace building, with a water-power or right, for the term of ten years, Curtin to pay an annual rent of $1 and all taxes assessed on the property during the term. Curtin also agreed “ to repair, improve and rebuild said furnace building, and put the same in proper condition for manufacturing iron, and to operate the same in the manufacture of iron.” lie undertook to complete the repairs and have the furnace in operation within three months and seven days from the date of the lease, and that all the improvements should belong to Long and Furst at the expiration of tho term ; provided that if ho should surrender the premises at the end of three years he should own one-half interest in said improvements. He also had the privilege of buying part of the land and the water-*542right, at a stipulated price, within one year from date of the lease.
The furnace had not been in operation for more than twenty years ; originally it was a charcoal furnace, had been changed to an anthracite furnace, and had always been run by waterpower. The forebay had rotted, and the water-wheel, shafting and machinery had decayed, or had been removed: The .buildings consisted of the furnace, a stone structure called the “ stack,” about thirty-eight feet square, and a casting-house, built of stone, fifty-nine' feet'long and forty-three feet wide, and one story high. These were in a somewhat dilapidated condition, especially the casting-house, a portion of its walls having fallen and its roof become worthless. There had been a bridge, or bridge-house, from the bank to the stack for the purpose of wheeling stock into the furnace, but the wood-work had so rotted that it needed rebuilding.
Curtin immediately took possession and began the improvements. The outer walls of the stack required little repair, and. its general appearance remained the same' as before. Its north side was the south wall of the casting-house, and needed no repair. He tore down the-gable of the north wall, a small portion of the east wall, and the greater part of the west wall to within about four feet of the ground, of the casting-house, the parts taken down being unsafe. These parts were not rebuilt with stone, the openings were encased with boards, and a new roof was put on the entire building, with a new ventilator at the top. He .erected an engine-house, forty-three feet by twenty feet, and placed in it. the engine with attachments and necessary machinery for running ; also a boiler-house, thirty-five feet by fifteen feet, and placed therein the boilers. He tore down an old stable that stood on the premises, using it as the principal part of the material for the engine and boilerhou'ses. • The bridge, or bridge-house, was also rebuilt.
There is no material conflict in the testimony respecting the condition of the property at the date of the lease, and of the improvements made by Curtin. It is manifest that extensive and costly improvements were necessary before iron could be manufactured. These the tenant was bound to make — they constituted the rent, except taxes, for the whole term, or the half interest in them was to be the rent if he elected to terminate the lease at the end of three years. In no event had he the right to remove the improvements. "Whatever was necessary to-put the furnace in proper condition for manufacturing iron, he covenanted to do, whether it was repairing or rebuilding. He was as much bound to rebuild the forebay and water-wheel, and replace all proper machinery for running the furnace by water, as he was to repair the stack, unless the agreement *543authorized the substitution of steam. It is true that the improvements to be made were not specified in detail, and that no value was named, and that the stipulated rent was $1 per annum. But for the whole term the landlords were to have all the improvements; these had real value, and were actual compensation for use of the land, though the parties did not choose to express the fact in very words. The learned judge of the common pleas was right in construing the lease to involve a building contract, and that the property was bound for improvements made under the terms of that contract, if the improvements came within the mechanics’ lien laws. Where the tenant contracts with the landlord to build, or to add to or repair buildings, to be paid for by the landlord, either in money or the use of the premises, he is the landlord’s agent, and the building is liable to a mechanics’ lien as in all other cases of contract: Hall v. Parker, 94 Pa. St. 109.
Hid the lessors authorize the substitution of steam-power? This is not determined by their right to hold all the improvements which the lessee might choose to make, but by the contract, which is to be interpreted in the light of the circumstances. The subject of the lease was an old furnace property, wLh water-power or right, and the only power that ever had been used in operating the furnace was water. There is not a word in the contract indicative of a purpose that new buildings should be erected other than rebuilding the old, or that other power should be used than that mentioned in the lease. All that the landlords could demand was, that the furnace be operated by water, in the same manner as it formerly had been ; all that the tenant was authorized to do was to bring that power into operation ; and persons dealing with tenant or agent for the making of improvements, were bound to take notice of the extent of his authority, for aside from the contract there is no evidence to bind the landlords for anything. Nothing in the relation of landlord and tenant implies authority in the tenant to make miprovements subject to a lien on the landlord’s property. The covenant to repair, improve and rebuild said furnace building includes erection of no building of a character differing from the old. An agreement for repairs and making repairs accordingly would not subject the property to a lieu — the property would not have been liable to lien for siich repairs as were necessary to run the furnace by water. The danger to the landlords would be far greater upon a contract for the introduction of steam-power, for in such case the property would be subject to a lien for the new buildings and machinery. It cannot be presumed that the parties contemplated abandonment of the water-power in absence of expression to that effect. As well might it be contended that the landlords authorized the *544erection of a rolling-mill, as that of engine-houses' and boiler-houses, and placing engines and boilers therein. A rolling-mill, though for manufacturing iron, was not intended nor was steam-power for the furnace. Therefore, as against the landlords’ property, the engine-house and boiler-house and the fixtures therein, are not the subjects of mechanics’ lien.
The plaintiffs claim, also, for work and material furnished for the repair of the stack, on the ground that the furnace is a new building; they are not entitled to a lien for alterations or repairs, even if made by express order of the landlord, the Act of May 1st 1861, P. L. 550, not being in force in Clinton county. With respect to the merging of old buildings in new, it was said in Miller v. Hershey, 59 Pa. St. 64, “ The idea which runs throughout all the cases is newness of structure in the main mass of the building, that entire change of external appearance, which denotes a different building from that which gave place to it, though into the composition of the new structure some of the old parts may have entered. This newness of construction must be in the exterior, the main plan of the building, and not its interior arrangements. . . There may be a lien for a new structure added to an old one, such as a kitchen or side building ; as seen in Nelson v. Campbell, 4 Cas. 156; Lightfoot Krug, and Pretz’s Appeal, 11 Cas. 348 and 349, and Harman v. Cummings and wife, 7 Wr. 322. But the lien there, is for the new structure.” In Parrish & Hazard’s Appeal, 83 Pa. St. 111, upon elaborate review of a number of prior decisions, it was decided that substantial buildings made near an old building, for permanent purposes, and so connected with the original structure as to make their connection as available and essential as if built beside its walls, are additions of material parts to the original structure, and when they serve all the purposes that actual additions would serve, and their extent and value are significant enough to give notice to purchasers and creditors of the change in the character of the property, the work and the material therefor, and the machinery placed therein are subjects of mechanics’ liens under the Act of June 16th 1836. There the additions were made by the owners of the iron works and consisted of a new engine-house and boiler-house, in which were placed an engine and six boilers, all upon the furnace property, and they served all the purposes of the furnace that actual additions would have served. The claims were filed for the machinery against the new' houses and machinery therein, together with the ground necessary for their, enjoyment, and were sustained on the authority of Nelson v. Campbell, 28 Pa. St. 156; Lightfoot v. Krug, 35 Id. 348; Pretz’s Appeal, Id. 349, and Harman v. Cummings, 43 Id. 322, which rule that an *545addition toan old building isa new structure, within the intendment of the Act of 1836. It was also remarked that if the buildings be regarded as ordinary out-liouses, the same process of reasoning that supported the liens against additions in those cases, requires that the liens against the engine and boiler-houses and machinery therein, should he supported under the Act of April 21st 1856.
There is a marked difference between the case of an addition to a building, and the merging of an old building into a new one. A kitchen or wing added to a dwelling, does not transform the dwelling into a new erection; nor will an old furnace building become new by the addition of an engine-house and boiler-house. A lien may attach for tlie additions, but not for alterations or repairs of the old building. Where, for the purpose of enlarging a building, an addition was put up, seventeen feet in front, and running back to the rear of tlie building, and many changes were simultaneously made in the old portion, it was held that for the erection of the addition a lien arose binding the entire structure, but not for the alterations in the old part: Harman v. Cummings, supra.
That the stack and casting-house constitute the furnace building named in the lease, and that they externally appear to be the same structures used more than twenty years ago, seems too plain for doubt. It is scarcely pretended that the outer walls of the stack have been materially changed. Patching tlie broken stone walls of the casting-house with boards and putting on a new roof evidence repairs, not newness of structure of the mass of the building. The new bridge did not merge the old' furnace building. Had the proper work been done for utilizing the water-power it would have been a repair. It may be conceded, perhaps not doubted, that for the additions of the engine-house and boiler-house and machinery therein, under tlie Acts of 1836 and 1856, the property of the landlords would have been bound by the mechanics’ lien, had tlie contract authorized their construction; but for repairs and alterations of the furnace building, though expressly authorized, there was no lien.
This claim is filed against the entire premises for work done and materials furnished for the erection and construction of a casting-house and furnace, bridge-house, engine-house and boiler-house, known as the Mill Hall Furnace, and would be good if the main building were a new erection ; but the facts bring it within the ruling in Wharton, Bros. & Co. v. Douglas, 92 Pa. St. 66. That ease arose prior to the Act of June lltli 1879, P. L. 123, which requires the court, “in any stage of the proceedings to permit amendments conducive to justice and a fair *546trial upon the merits.” If the plaintiffs were entitled to a lien it would be important to consider whether they had right to amend their claim.
Judgment reversed.