I. There are thirty errors assigned, and twenty-three points in the argument of counsel for appellant.
To pass up>on each assignment of error is, in our judgment, unnecessary, because we think many of them belong to the same class and may be disposed of without separate consideration.
It appears that a part of the wall of one of the buildings was not as thick by four inches as provided in the contract, and that the windows in the basement story of one of the' buildings were set lower than the plans provided, and. that the work was not completed by the time stipulated.
The plaintiffs introduced evidence tending to show that these departures from the contract were either acquiesced in by the defendants, or caused by their acts, and that the buildings were accepted by them as being done in fulfillment of the contract.
This evidence was objected to by defendants, because not competent under the issues. The objections were overruled and the evidence admitted. The court instructed the jury as follows:
“1. In the first count of their petition the plaintiffs allege that they have performed their part of the contract, and that there is an amount due them thereon. Their right to recover on this count depends, then, on whether they have established their claim that they have performed their part of the contract. If the proof establishes either one of the following states of- fact, the plaintiffs will be entitled to recover on this count — First, that they have performed all the work which they undertook to perform substantially in the manner and within the time in which they agreed to perform it; or, second, that they performed a portion of said work in. the manner and within the time agreed upon, and were ready and willing to perform the balance according to the terms' of the agreement, but were prevented from so completing the same by some act or omission bf the defendants: or, third, that with *465.full knowledge of the manner in which the work was done, the defendants have accepted the same as a full performance of the contract by the plaintiffs. But if the proof fails to establish either of these states of fact, the plaintiffs cannot recover anything on this count of the petition.
“2. Your first inquiry, then, is whether the plaintiffs have performed the work they undertook to do in the manner and within the time in which they agreed to do it. What is required of them in the performance of the work is a substantial compliance, in the manner of doing it, with the plans and specifications. If they have deviated from the plans and specifications in matters which do not affect either the strength, value or convenience of the building, such deviation would be unimportant, and would not defeat their right to recover on the contract. But if in doing the work they have, on their own motion, so far departed from the plans and specifications as that the building is less valuable than it would have been had they followed the plans and specifications, they cannot, in this action, recover the balance which is unpaid under the contract, unless the defendants have accepted the work as done as a performance of the contract.
“3. If you should find from the evidence that plaintiffs performed the work actually done by them substantially as they agreed to do it, but that they have failed to do some portions of the work provided for in the contract, it will then be material for you to determine whether such failure was owing to any fault on their part. If they have omitted any material portions of the work which the defendants have not consented to or waived, or which was not caused by some failure of the defendants to perform some portions of the contract on their part, they cannot recover on said first count of their petition. But if they were ready and willing to do the omitted portions of the work (if there be any) and their failure to do the same was owing to the failure of defendants to furnish the noeessary material for doing it, their failure to do such *466omitted portions of the work will not defeat a recovery by them on the contract.”
To the giving of which instructions defendants excepted. The admission of the evidence above referred to, and the' giving of these instructions, was erroneous.
1. contract-pleading. The plaintiffs averred a performance of the contract, and it is well sebt-lecL that under such averment it is 110^ competent to show that a performance was waived, nor that the contract was altered by the act of the parties. A party cannot sue upon one contract and recover upon another. Lumbert & Co. v. Palmer, 29 Iowa, 104. For the latest utterance of this court upon the question, see Edgerly v. The Farmers’ Insurance Co., 43 Iowa, 587.
It may be conceded, as claimed by counsel for appellees, that “where a party to a contract is prevented from performing his part of it by the other party, he cannot therefore abandon it and sue on the quantum meruit, but is entitled to recover as in case of a complete performance.” But it does not follow that, under our ’system of fact pleading, he can allege a performance of the contract, and prove facts in excuse of performance.
2 _. moa_ ifleatiou of. II. We think the second instruction is also erroneous in directing the jury “that a deviation from the plans arLCi specifications, in matters which do not affect either the strength, value or convenience of the building * * * * * * would be unimportant, and would not defeat the right to recover on the contract.”
A party who contracts to have a building erected according to certain plans and specifications cannot be compelled to accept any kind of a building which, in the judgment of others, is equal in strength, value and convenience. It may be of great importance to him to have the building to suit his ideas of convenience. It seems to us this instruction, if not intended to have that effect, would be liable to lead a jury to believe that any building of equal value, strength and convenience would fill the requirements of the contract, and that *467the instruction should have been limited to slight and unimportant deviations.
3 _. den of proof. III. The court further instructed the jury as follows: “14. The plaintiffs by the contract were to* complete the building by the 1st of November, 1874, unless they were delayed by want of material. If they failed to complete said building by that time, and were not delayed by want 0f material, they would be liable for whatever damages the defendants have sustained by reason of such failure. The rental value of the building during the time which defendants were kept out of it, by reason of such failure, would be the measure of defendants’ recovery on this claim. But the burden is on the defendants to establish both the fact of the failure and that it was not caused by want of material, in making out the claim. ” To which defendants duly excepted.
The latter part of this instruction was erroneous, even conceding that evidence in excuse of performance of the contract was competent under the issue. When the defendants established the fact that the buildings were not completed by the 1st day of November, 1874, as the case then stood, plaintiffs were in fault, and the burden was then on them to show a valid excuse for their failure to perform the contract.
4 _. sev. severaity. IV. It is claimed by appellant that the contract is several, and not joint, and that plaintiffs cannot maintain a joint aetion upon it. In this position we do not concur. By ^ very ^ermg 0f ftie writing, both of the plaintiffs are bound to the defendants for the entire work and labor necessary in the erection of the block of buildings. For any failure both are liable, and upon that theory the defendants set up joint counter-claims. The mere fact that Smith was to receive a certain sum of money for the work and labor, and Fauble a certain other sum, does not make it necessary that they should bring separate suits.
There are other errors assigned, among which is the ruling of the court upon evidence as to the acceptance of the build* *468ings, and as to what is extra work, etc., which we do not deem it necessary to determine, as upon a new trial it is not likely the same questions will arise.
For the errors above discussed the judgment must be
Reversed.