How much is that accessory dwelling worth? How do we really put a value on it? It’s not always easy to figure that out in real estate, so I wanted to share some of the issues I tend to think through as an appraiser when there is an accessory unit on a property. Anything you’d add? I’d love to hear your take.
Things to consider when valuing a property with an accessory dwelling:
1) Comps: How much are other homes with accessory units selling for? This is a fundamental question to ask. Since data is often limited we might have to look through years of neighborhood sales (or competitive neighborhoods) to try to find something that has sold with an accessory dwelling unit (ADU). Even if the sales are older or a bit different in size we can at the least come up with a percentage or price adjustment to try to get a sense of what the market has been willing to pay. Ideally we’d find three model match sales in the past 90 days, but that’s probably not going to happen. Remember, we might not use the really old sales as comps, but we can still use some of the older data to get a sense for how the market has behaved regarding accessory units.
2) ADU Minimum: At a minimum an accessory unit needs to have a bathroom, sleeping area, and kitchen. This means an outbuilding without a bathroom really isn’t an accessory unit. And that Man Cave / She Shed isn’t an accessory dwelling because it’s basically a game room meant for hanging out instead of living.
3) 2nd Unit or Not: Are we dealing with a second unit or an accessory unit? It might sound like I’m splitting hairs to ask this question, but there is actually a difference between a full-fledged second unit and something that would be classified as an “accessory” unit (or “Granny flat”, “Mother-in-Law” unit, or “Guest Quarters”). I wrote a post here to describe the difference. In short, whether something is a full second unit or merely an accessory dwelling could potentially change the way we approach valuing the unit and which comps we choose.
4) Just a House: How much would the property sell for if it just had a house without an accessory unit? This doesn’t help us put a value on the accessory unit, but in a sense it helps us start gauging value for the neighborhood. This at least gives us a place to begin.
5) Combining Square Footage: Often times an accessory unit’s square footage gets lumped into the main square footage of the house. This happens in MLS and sometimes it happens in Tax Records. So we might read a home is 2000 sq ft when in reality the main home is only 1400 sq ft and the accessory unit is 600 sq ft. In this example we don’t really have a 2000 sq ft house but rather a 1400 sq ft house with an accessory unit. The question becomes, could the subject property sell on par with homes that are 2000 sq ft? Maybe. Maybe not. This is where we have to do research. I will say quite a few properties are priced based on a lumped square footage and then they end up sitting instead of selling. This is not always the case, but it reminds us to be careful about assuming a home with an accessory unit is always going to have the same value as a larger home.
6) Permits: Was the accessory unit permitted? If you are hoping to see more significant value recognized for an accessory dwelling, having permits is a key factor. My friend Gary Kristensen in Portland wrote a post on ADUs and he says, “Provide the appraiser and your lender with documentation that your ADU was legally permitted. Also, list information about rental income, expenses, and detail construction costs (if your unit was recently constructed).” Good advice, Gary.
7) Rent: Can the accessory unit be legally rented? What is the market rent? This is where we might use the Income Approach to come up with a value (another blog post). Imagine an accessory dwelling has a market rent of $1000 per month. Now imagine an appraiser says the extra unit is worth $10,000. Does that seem reasonable? Doesn’t it seem low right away since the unit would be 100% paid for after 10 months? Or imagine a unit rents for $300 but it’s being given $150,000 in value. Doesn’t that seem excessive based on the low rent? Thus sometimes when we know market rent we can begin to sniff out whether a value adjustment is even approaching reasonable.
8) Square Footage Adjustment: If I’m adjusting $50 per sq ft for extra square footage in my report, would it be reasonable to see that same adjustment for the 600 sq ft accessory dwelling? This is only a question I ask myself. There isn’t a constant where the market will pay the same amount for square footage for the main dwelling and something else (converted basement, converted garage, accessory unit). Part of it depends on quality too. If the extra unit has a quality clearly below the main house, it’s probably not reasonable to see buyers pay the same amount for square footage outside the house. Though if the quality is the same, we might be looking at an adjustment that is similar or the same to that which is given to the house. Again, there is no rule here. This is only a question I ask myself in the background when approaching an accessory unit. I would never automatically give an adjustment like this. Remember, square footage adjustments are NOT based on the entire value of the property divided by the square footage.
9) Cost vs. Value: We all know the cost of something doesn’t necessarily translate to the value, but cost can help us gauge quality. There might be a difference in value for an accessory unit that cost $125,000 compared to $15,000, right? This is basic logic, but let’s not overlook the importance of it.
I hope that was helpful.
Questions: Anything you’d add? Did I miss something? If you work in real estate, how do you come up with the value of an accessory unit? I’d love to hear your take.
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