I work in an assessment capacity - so don’t quite agree with G about the tax assessor “wanting a higher number” – most often, the assessment in towns is fair market value…and is based on about ~200 arms-length sales of other “like” properties in the neighborhood or town from the previous year. The factors taken into valuations are: quality and condition of house (and quality of build/construction), acreage/lot size, zoning and quality of neighborhood, age of structure, etc – and is revised every single year.
My state’s DOR has a law that property values released by assessors should fall within a range of ten percent above/below their full cash value…
In the town I work in, our assessments are almost alwayslower than what real estate appraisals appraise the property for – more often than not by at least six figures! Avg home valuation in this town is about $1.2 million.
Don’t forget to talk to your town’s Assessor, and see how the Principal Assessor has the building[s] and property valued. You can request a building card (sometimes called a “field card” or “property record card”) that will have a breakdown also, of your property.
G is right that equestrian-related structures often have little to no value in terms of bolstering property value; generally, anything without living area is going to be valued for much lower than cost. You will never, in my experience, have a valuation that rivals what the cost was for an indoor or other equestrian structure.
It may be worth it to find an equestrian appraiser, as for many appraisers, they are looking for clients interested in demolitions or subdividing bigger lots to make multiple housing entities… so to them, your buildings and structures are effectively worthless.