Metamorphic
Senior Member
- Joined
- Mar 15, 2008
- Professional Status
- Certified Residential Appraiser
- State
- California
This really shouldn't be that hard.
The lack of readily available data for an ADU is not convincing evidence of the lack contributory value for an ADU. The ADU might be worth nothing, but that's a not a reasonable starting assumption. If the appraiser wants to make that case he'd have to present some convincing data.
If you take the more likely option....that the ADU contributes value.....there are several options for beginning to understand the potential size of the contribution.
-Prior sale analysis. Comparison of historic sale data for the subject with similar age sales without the ADU should provide a value indication for the ADU.
-Analysis of ADU or inclusion of Comps from nearby competitive markets that have ADUs.
-Analysis of the subject based on the combined utility of the 1,900 main home and the 600sf ADU. It shouldn't be that hard to find a 2500 sf comp somewhere. While not all buyers would accept the detached GLA at the contributory rate for normal GLA (small children), there is certainly a group that would not find dis-utility in the detached ADU and many that would find superior utility.
Particularly at 1,900 sf for the main home...you're a long way from superadequacy for living space on a lot in most markets in this country. My starting assumption would be 100% contributory $/sf value for the ADU and I'd be looking for my market data to pull me away from that number. I'd suspect that in a neighborhood in the maturity or gentrification you'd see 100%; maybe half that if the neighborhood is in the development or decay phases.
Its really important remember that your'e not talking about a superadequate main home to begin with.
The lack of readily available data for an ADU is not convincing evidence of the lack contributory value for an ADU. The ADU might be worth nothing, but that's a not a reasonable starting assumption. If the appraiser wants to make that case he'd have to present some convincing data.
If you take the more likely option....that the ADU contributes value.....there are several options for beginning to understand the potential size of the contribution.
-Prior sale analysis. Comparison of historic sale data for the subject with similar age sales without the ADU should provide a value indication for the ADU.
-Analysis of ADU or inclusion of Comps from nearby competitive markets that have ADUs.
-Analysis of the subject based on the combined utility of the 1,900 main home and the 600sf ADU. It shouldn't be that hard to find a 2500 sf comp somewhere. While not all buyers would accept the detached GLA at the contributory rate for normal GLA (small children), there is certainly a group that would not find dis-utility in the detached ADU and many that would find superior utility.
Particularly at 1,900 sf for the main home...you're a long way from superadequacy for living space on a lot in most markets in this country. My starting assumption would be 100% contributory $/sf value for the ADU and I'd be looking for my market data to pull me away from that number. I'd suspect that in a neighborhood in the maturity or gentrification you'd see 100%; maybe half that if the neighborhood is in the development or decay phases.
Its really important remember that your'e not talking about a superadequate main home to begin with.