How do I value an office space on an industrial highway with no comparable sales or renters?
I've spoken to 3 real estate agents so far and none have been able to help me - very few do commercial in this area (small town near a big city). 

There have been no sales in the near term, so say the agents. Most people on this road own manufacturing/machine shops and do not rent, so determining a fair rental price is really tough. Calculating a cap rate seems impossible.

The building currently has a month-to-month residential tenant (against code) paying $1200/month for 2300 sqft. But they are not going to stay long, so I need to figure out what the rent is. I am 100% interested, I just can't seem to value it properly.
[{"id": "h1bs3lp", "text": "Could you call some local businesses and see how much they would pay? \n\nAre there any commercial appraisers in the town?  They are certified usually in valuation. Brokers can't  always give you that information for liability reasons.", "replies": [], "depth": 1}, {"id": "h1btr6z", "text": "Did you ask commercial brokers based in the big city?\n\nYou can value it based on replacement cost if it is basically vacant.\n\nYou can go out further, most likely as long as it is along the highway, to look for similar places for rent. Even if you have a NOI figure, you need a cap rate to properly value it.\n\nIf the nearby commercial properties tend to be owner-occupied, you can try to figure a cap rate from market rents and those sales.\n\nIf residential rent is similar to office rent on a per sq ft basis, you can figure NOI based on a modified gross lease at $6 per sq ft (annually).", "replies": [{"id": "h1bu6c3", "text": "Thanks. Seems like i really need to find a broker/appraiser familiar with this area.  \n\n\nWill an appraiser give you a ballpark evaluation without requiring payment? I need to make an offer and go under contract before it's worth spending $500 on an appraisal.", "replies": [{"id": "h1c4ggx", "text": "Draft an LOI that outlines how you'll come to a price. If both you and the owner agree on the method for determining the price, then you can move forward to agree on the inputs for the formula.", "replies": [], "depth": 3}, {"id": "h1cj04d", "text": "Gonna cost way more than $500. An appraiser will not provide a value without payment in most cases.", "replies": [], "depth": 3}, {"id": "h1dcruc", "text": "Commercial appraisals are several thousand dollars.\n\nBut I don\u2019t think you need an appraisal at this point. - based on what you\u2019ve stated.", "replies": [], "depth": 3}], "depth": 2}], "depth": 1}, {"id": "h1bujye", "text": "call a commercial agent or appraiser in the big city.  \n\nThis is one of those things where you have what you have, and sometimes its not ideal.  There probably is info in other similar locations you can use, but how to adjust that or what to use is something that is likely to need some area expertise.", "replies": [], "depth": 1}, {"id": "h1bynwd", "text": "Go to the nearest city look up from Loopnet.  \n\nIncome approach is what you really need since there are no comps.", "replies": [{"id": "h1chjex", "text": "Income approach? What do you mean", "replies": [{"id": "h1cia8t", "text": "Look it up. Appraisal income approach.", "replies": [], "depth": 3}, {"id": "h1cpw1s", "text": "You estimate the income of the gross and factor in desirability and risk to get your cap rate then you find the price\n\n1200 x 12 is 14400. Say the location is like 8-15 cap rate. The higher the cap rate the lower the asking price. A 15% cap rate is like 100k I think.\n\nYour goal is to find that ratio of high cap rate to entice buyers and also get the value for seller", "replies": [{"id": "h1hnoan", "text": "where in there States can you buy something for a 15 CAP?", "replies": [{"id": "h1i2e48", "text": "Wherever this guy is \ud83d\ude02", "replies": [], "depth": 5}, {"id": "h28eirc", "text": "It\u2019s probably easy to find high cap rates for something like trailers in small town, but you probably can\u2019t get loans for them. As soon as a property is nice enough and expensive enough to be able to support loans, I\u2019m sure that the cap rate would drop quickly.", "replies": [], "depth": 5}], "depth": 4}], "depth": 3}, {"id": "h1cpzpr", "text": "You need to find out what other people are paying per dollar of income.  What are the cap rates on recent sales as close to your prop as possible? Apply that cap rate to your property's income to determine a value. Widen that cap rate out 25bps to account for your property not having close comps/your area not being desirable for industrial / rural location. Then maybe widen again since lenders and buyers worry about retenanting in rural locations.", "replies": [], "depth": 3}], "depth": 2}], "depth": 1}, {"id": "h1cjnvf", "text": "I would recommend driving around the area and asking the opinions of brokers who have their signs out. They will generally have the expertise on the area and have an idea of what you could rent the property for. \n\nThe value of this type of property is mostly driven by what you can rent it for.", "replies": [], "depth": 1}, {"id": "h1d1cox", "text": "What are you going to do with the property? Use it or lease it? If there aren't any leased commercial buildings in the area there may be a reason for that. If you're going to use it I'd use replacement cost since your alternative would be to buy land and build.", "replies": [], "depth": 1}, {"id": "h1d4js8", "text": "How much rent will someone pay for the space?", "replies": [], "depth": 1}, {"id": "h1dce1f", "text": "Your question isn't clear. Are you looking for a property value? Or are you trying to determine market rent for the property? \n\nI'm guessing you are the owner and trying to lease the space to a new tenant?", "replies": [], "depth": 1}]