I actually have experience with this while I was re-financing recently.
My unpermitted addition (a loft within a condominium with 18 ft. ceilings) was basically ignored in the appraisal process.
I asked the appraiser about unpermitted additions in general and he said, “As long as the addition looks good – and looks up to code – then I just ignore it in the appraisal process. It won’t help or hurt in the appraisal – it’s just there.”
Which seems fair. If you want “credit” for it, you should go through the permit process. If you don’t care, just make sure it looks nice and don’t bother. Just my 2 cents.
