General answer for exterior express is $700 to $850 per SF building includes expense for site work, building, F/F/E, soft cost, and real estate. So, if shell is 1,500 SF, estimated project cost would be $1.05 million (1,500 X $700).
Specific answer depends on public need for carwash. Here, total available market in defined trade area is a function of DIY segment (home, self-serve) and DIFM (conveyor, in-bay).
Public need is determined with demand/supply balance. If 40 percent wash at home and 20 percent use self-serve, 40 percent would be available to support a new wash. Whereas suitability of location is usually determined with attraction rate (i.e. 1.0 percent).
In other words, to attract more than 80 cars per day (8,000 X 0.01), the site would need to “pull” customers away from competition as well as from driveway.
Test the sanity of this.
80 CPD X 312 days X $8.50 average sale = $212,000 (rounded)
How likely is it the site can capture sales of $212K from 12,000 people of which 40 percent wash at home and 20 percent self-serve?
Another attribute of new wash is ability to support debt. Is $212K enough?
$212K X 0.5 expense / 12 months / 1.5 debt service coverage = $6,000 rounded
$6,000 based on general terms and conditions is equivalent of $900,000 amortization.
$900,000 is equivalent total project cost of $1.125 million ($900,000 / 0.8).
EBTD = ($212,000 X 0.5 expense) – ($6,000 X 12)
EBTD = $34,000
Risk reward = $34,000 / ($1.125 mil X 0.2)
Risk reward = 0.15:1
This is type of risk reward a number of self-serve developers chased before the big bust. Now, most are underwater or vacated.
I’m not saying 12,000 cannot support a conveyor because I know certain markets that do so. However, the prospect of injecting equity of a quarter million dollars or so merits more than napkin analysis.