From the south heading northbound on Hwy 99: Heading north, take the Western Ave exit. Continue on Western approximately .5 miles to Broad St. (Seattle Sculpture park is on the left side). Continue past Broad St., and just before the next light (Denny Way), move in to the far right lane. On your left, you will see the dark grey NW WorkLofts Building (U-shape building with greenery in the center). Seattle Aesthetics is located on the street level of that U-shaped building at the crosswalk of Western Ave. and Denny St. Signage is clearly marked on the street-front windows.
As you continue through the light in front of the building, you will see an alley on the right side that leads to a U-Park lot. You can turn right into the alley to reach the U-Park lots or go around the block and access the paid parking lots through the alley. To circle back around the block, take the first right (after the alley) on 1st Ave W, turn right at the next block (John St.) and then turn right into the alley. There are two parking lots accessible from this alley. You can also look for parking along Western Ave.