Opinion by
Mr. Justice Moschzisker,On May 15, 1916, plaintiff sent defendant a written offer to support a certain building, in the City of Pittsburgh, while the latter was excavating an adjoining lot; this proposal states the price, $1,300, the materials to be used, and the manner in which the work shall be done; it was accepted on the stipulation that the structure should be kept in its then “present condition” and *193bracings placed across two adjoining alleys. Defendant, in tbe meantime, had commenced to underpin tbe building, but tbe results were not satisfactory, and, June 23, 1918, plaintiff contracted to do, in addition to tbe work already agreed upon, all tbe excavating and underpinning, for another $1,300. Pursuant to these contracts, plaintiff proceeded with and claimed to have completed tbe specified work. Subsequently, defendant paid $800 on account and was allowed a credit of $88; but refused to pay tbe remainder of tbe agreed consideration. Tbe present suit was brought to recover this balance, and defendant filed an affidavit of defense admitting tbe contracts, at tbe same time denying that plaintiff bad performed tbe work called for therein; in consequence of which, it averred, tbe building in question bad sunk and swayed over tbe property line onto tbe next lot, causing defendant an expense of $2,500 to re-align it. A certificate was asked for tbe difference between this last-mentioned sum and tbe amount claimed by plaintiff; but tbe latter, in reply, denied all matters of set-off.
At trial, plaintiff admitted that, in accomplishing tbe stipulated work, it bad not strictly complied with tbe methods provided in tbe written agreement, but claimed, in extenuation, that defendant bad rendered such performance impossible; further, that, while tbe work bad not been executed in every particular in strict accord with tbe contracts, yet there bad been substantial compliance, and any sinking of tbe structure, or movement of tbe building off its proper line, was in no manner or degree properly attributable to tbe way in which plaintiff bad done its work. All tbe issues involved were submitted to tbe jury in a charge concerning which no complaint is made, and plaintiff recovered a verdict for tbe full amount of its claim. Defendant subsequently filed motions for a new trial and judgment n. o. v.; both being refused, judgment was entered on tbe verdict, and this appeal ensued.
*194The only questions stated for our consideration are, first, whether the trial judge erred in admitting certain evidence over defendant’s objections, and, next, whether the latter was entitled to judgment non obstante veredicto.
In its reply to the affidavit of defense, plaintiff alleges defendant interfered with the progress of the work, thus rendering compliance with the details of the contracts impossible. The first assignment relates to the admission of testimony as to the conditions on the ground when plaintiff’s operations were commenced; but the evidence therein referred to is merely explanatory of the manner in which the work was done and how defendant interfered with its progress. The same may be said of the second assignment. The allegations of defendant’s interference, contained in plaintiff’s reply, are, we think, sufficient to justify the testimony here complained of. The Practice Act of May 14,1915, P. L. 483, does not require the details of matters intended to be proved, or the evidence relied upon, to be set forth in the pleadings; had defendant desired greater particularity, it should have moved against plaintiff’s reply in the manner provided by this statute; see section 21 (P. L. 487) thereof and opinion of that excellent jurist, the late Judge Irwin, of Washington County, in Sturtevant Co. v. Regan et al., 26 Dist. R. 189.
The third, fourth and fifth assignments complain of the admission of evidence to show that, as a matter of fact, the alleged disturbance of the building occurred after plaintiff had finished its work. This was objected to on the ground that no sufficient notice is contained in plaintiff’s reply of any such answer to defendant’s claim of set-off. The reply denies the structure either sank or swayed through the fault of plaintiff; and the evidence now under consideration is to the effect that the machinery in the building had operated smoothly during.the time plaintiff was engaged in performing its work, whereas this state of affairs did not continue when the Eichley *195Co., which was subsequently employed by defendant, to put the building back on its line, took control; that, on the contrary, after this latter concern went to work, the belts on the machinery required readjustment. The circumstances shown by this'evidence tend to support plaintiff’s allegation that the building did not sink or sway by reason of its method of work; and a pleader is not obliged to aver his means of proof: Moore v. Susquehanna Mutual Fire Insurance Co., 196 Pa. 30, 34. We are by no means convinced the evidence in question was improperly accepted.
The sixth and seventh assignments are based on the admission of a plan showing the position of the building with reference to the property line; in this we see no reversible error.
The eighth assignment relates to testimony introduced over defendant’s objection that it was not proper rebuttal. The order of the admission of evidence is a matter for the trial court, which does not call for review except in extreme instances, and this is not such: see opinion of our Brother Walling in Aland v. Pyle, 263 Pa. 254, and cases there cited.
The ninth to twelfth assignments, inclusive, which .complain of answers to certain of defendant’s points, might be refused consideration because they are neither referred to in nor comprehended by appellant’s statement of the “questions involved.” The answers to the points in question, however, accord with the rulings on the evidence, which we have already discussed; and the guiding principle, on which they are based, is that one who impedes the performance of a contract by another cannot take advantage of. his own wrong, to prevent a recovery: Grove v. Donaldson, 15 Pa. 128, 135; Gast v. Miller (Supreme Ct.), 2 W. N. C. 361,.362; Wilson v. Crowell, 48 Pa. 58, 66.
The final assignment goes to the refusal of judgment for defendant n. o. v.; as to this, it is sufficient to say ¡that, since the evidence on the issues involved was con-. *196fiicting in many particulars, the case was necessarily for the jury. We see no merit in any of appellant’s complaints.
The assignments are all overruled and the judgment is affirmed.