The plaintiffs contend, under their motion to review the judgment, that the finding by the trial court to the effect that the contract between the parties was for but a part and not for all of the services actually rendered by the plaintiffs was erroneous and should have been set aside as contrary to the weight of the evidence; that then a finding should be made that the services which were in fact rendered were all under the contract, arid, the value being fixed at $1,750, that amount should be allowed as damages.
There is no dispute but that when defendants went to plaintiffs’ office and arranged with them for their professional services the defendants had not then purchased or decided upon the purchase of any particular lot on which to erect a factory building. It is also without dispute that some sum was mentioned by defendants as being the maximum cost of any building which they could undertake to erect. It is also without dispute that sometime prior to the receiving by plaintiffs of sealed bids from contractors to do the work under the completed plans and specifications which they had finally prepared, the defendants had abandoned the idea of putting up a building of their own and had made arrangements for the leasing of one.
There is sharp dispute between the witnesses as to whether or not the defendants did, after the completion of the preliminary sketches and the stating by plaintiffs of the approxi*292mate cost of a building which could be completed either under mill or concrete construction according to the general outline and scope of such preliminary sketches, direct the plaintiffs to proceed to completion with the plans, sketches, and specifications upon which complete and final bids might be received. There is also no question but that a very substantial part of the services rendered and performed by the plaintiffs were rendered subsequent to such order, if any such were given. The trial court was of opinion, as is evident from his written opinion and findings, that the plaintiffs had not met the burden of proof required of them as to their theory of the contract.
An examination of the record does not convince us that the trial court was wrong in so deciding, and his conclusions, therefore, in that regard must be and are upheld.
In the disposition of this case, therefore, it must be assumed that the entire services rendered by the defendants and found to be of the reasonable value of $1,750 were not rendered under and pursuant to the contract between the parties, but consisted in large part of matters and services in excess of those for which plaintiffs contracted and agreed to pay.
The issue as to whether the services were of the wide extent claimed by the plaintiffs or of the more restricted nature claimed by defendants, was squarely presented by the pleadings and was present all through the trial. It was of course incumbent upon plaintiffs, if entitled to recover under either theory of the case, to present to the court competent evidence upon which a proper assessment of damages might be made. The plaintiffs evidently elected to stand squarely upon their view and position as to the contract between the parties, and upon that alone. Plaintiffs continue to so stand upon that view, both by their motions in the trial court after trial and their motion to review here, no request for a new trial being made. Their entire evidence, both that by the plaintiffs themselves and by the architects *293called by them to also testify as experts as to the reasonable and customary charge for such services in the locality where they were rendered, all was to the effect that such charge Avas a rate of three and one-half per cent, upon the approximate cost of the proposed building. ■ All the witnesses included as necessary and essential elements of such method of computation and rate the entire services as rendered by plaintiffs, and to the full extent thereof, rather than of or upon the limited services under such a contract as was found by the court.
The difficulty now presented, however, is that,,while such method of computation would fit the situation covering the entire services, it affords no basis upon which a court or jury could properly arrive at an estimate as to the value of the services necessarily performed within the restricted field covered by the narrower contract as found by the court. There is no testimony as to the amount of time necessarily spent in the performance of the contract as so limited or any customary rate of compensation.for such limited services. There is nothing from which it is possible to say that the amount done under that contract was any certain or definite proportion of the entire work done and services rendered.
The court being confronted with this dilemma and evidently considering that it became his duty to assess damages in some amount to the plaintiffs, it being conceded by the pleadings that they were entitled to some, then determined that in his judgment the value of such services was $600. No basis is suggested in the opinion of the trial court nor by respondents here by which the sum of $600 can be arrived at as such valuation rather than $500 or $700 or any other sum.
The value of such services as were here rendered by plaintiffs was not a subject of general knowledge or such as comes within the wide field wherein courts can take judicial notice of certain classes of facts. The very nature of plaintiffs’ evidence as to the value of such services shows *294that proper proof of the measure of compensation in such matters is peculiarly one requiring the evidence of those familiar as experts with such work and the customary pay therefor in the particular locality where rendered.
That the trial court had knowledge from personal experience as to the reasonable value of services such as were rendered by the plaintiffs under the contract does not appear in the record. Though a trial court has particular personal knowledge or experience in such line of work from which he would be qualified to form a judgment upon such a matter, even then such particular personal experience could- not be used as a basis for making -such a finding. Neither jurors nor trial courts in arriving at their conclusions of fact .in any particular case can properly act upon -their special individual knowledge as to matters which are not of common knowledge. '
In matters outside of the field of general knowledge and in cases where the testimony of'experts or those particularly familiar with the matters at issue is necessary, the findings of all triers of fact, either court or jury, must be based upon testimony of witnesses or other evidence made a -part of the record. Kuder v. Waukesha Co. 172 Wis. 141, 178 N. W. 249; Menn v. State, 132 Wis. 61, 64, 112 N. W. 38; Shafer v. Eau Claire, 105 Wis. 239, 243, 81 N. W. 409; Johnson v. Superior R. T. R. Co. 91 Wis. 233, 237, 64 N. W. 753; Sherman v. Menominee River L. Co. 77 Wis. 14, 22, 45 N. W. 1079; Jones, Evidence (2d ed.) § 133.
In such a situation as here presented neither court nor jury has any more right to arrive at a conclusion of their own without testimony to support it than has a court or jury to disregard competent proper evidence as to the value of services where there is no contradiction thereof in the record. Ladd v. Witte, 116 Wis. 35, 40, 92 N. W, 365. It is only in cases where the value of attorneys’ services is at issue that a trial court may exercise his own independent judgment as to the value of such services so far as they were rendered in *295the case before him. ' There is good reason for such a rule and it has beén often recognized. Larscheid v. Kittell, 142 Wis. 172, 177, 125 N. W. 442; 2 Ruling Case Law, 1060; 6 Corp. Jur. 764.
The'defendants’ answer, quoted in the above statement of facts, contained allegations which should and must be treated as an admission to the effect that the sum of $200 was due to plaintiffs for their services. Upon such admission the plaintiffs might have moved the court under sec. 2892, Stats., for an order requiring the immediate payment of the amount so admitted, and such order could be enforced under the express provisions of said section, as might be a judgment or provisional remedy.
Such admissions of liability as were máde by the defendants in their answer herein are still binding upon them, and upon such admissions the plaintiffs were and are entitled to a judgment for the sum of $200, together with interest from the commencement of this action and their costs in the circuit court.
Although the defendants use language in their answer whereby they “offer to allow judgment to be taken against them in this action for the sum of $200 with costs,” still such language, when used in such a formal pleading as an answer, cannot be considered as an offer of judgment under sec. 2789, Stats., or as having any effect upon plaintiffs’ right to costs in the trial court or in any other regard.
Under said sec. 2789, Stats., the offer of judgment therein provided for must necessarily be embodied in some other document than the answer itself, for if such statutory offer of judgment is not accepted within the limited period it must be withdrawn from all consideration of the court until after trial, and cannot be used in evidence in any way (Bourda v. Jones, 110 Wis. 52, 59, 85 N. W. 671); nor can it be subsequently accepted after the period limited in the statute. Smith v. Thewalt, 126 Wis. 176, 105 N. W. 662.
But when, as here, such alleged offer of judgment is *296embodied in the answer itself, it becomes a part of the pleadings and therefore of the record of the case and is properly before the court, and may be offered in evidence and considered by the jury during the trial. Schoette v. Drake, 139 Wis. 18, 22, 120 N. W. 393, and cases there cited; Sims v. Mutual F. Ins. Co. 101 Wis. 586, 589, 77 N. W. 908.
The language used in the case of Landauer v. Kasik, 155 Wis. 376, 144 N. W. 974, suggesting, that a somewhat similar admission in the answer there before the court might be considered an offer of judgment as well as an admission, must be deemed qualified to the extent herein indicated.
By the Court. — Judgment reversed, and the cause remanded with directions to enter judgment for plaintiffs in accordance herewith.