Interesting thread
I like all the comments, but want to take issue on whether you need to "guarantee" the cost to cure estimate.
Let us not forget that this is appraising, an expression of opinion. An opinion is defined by my version of Webster as "a belief or idea, held with confidence but with out direct support or knowledge."
So long as there is a reasonable and credible basis for a professional judgement, we as professionals are not obliged to "guarantee or prove" any of our opinions. We must not have errors of ommission or commission, we must use correctly appropriate methods and techniques, and we must consider all relevant issues impacting value that a typical appraiser (or client) would expect in a similar type situation. What we must accomplish in our appraisal is avoid unsupported assumptions.
In this instance, Dan indicated that he has acknowledge what he believes to be a property defect and has a supportable basis for a cost to cure. He should at least explain that basis orally to his client and preferably in his written report as well. As many poster have noted, he should recommend that an structural inspection is probably warranted, and that based on the results of that inspection, he may need to revise his cost to cure. If he does those things, he has, at least it is my opinion, done what I would expect any appraiser to do, at least in regards to the structural issue.
As Mike G. implies, the function of the report would change the diligence required. Assuming this appraisal is for lending puroses, the above comments are germane. If the appraisal were ordered for the function of settling a lawsuit over faulty construction for this construction defect, a higher level of diligence would be required in determining the extent of the physical defect.
Regards
Tom Hildebrandt GAA