Future Reuse for Parking Structures

Hi Jeremy, We worked on a project where some parking was above grade, below a tall tower in a dense urban area. We convinced the owner to go to flat floor parking instead of sloped parking, and increase the floor to floor somewhat, so it could be turned into usable space once the future arrives. The project has not yet been built, though, due to other reasons. -Kjell

There's lots of great work out there on this topic, starting with the little sidebar in BuildingGreen / Environmental Building News back in 2003 describing John Reynolds' proposal that we design parking decks so they can turn into courtyard-style office buildings or residential developments.   We tried to implement this strategy in our Dalney building at Georgia Tech project.   The key impediment is that parking garages in the US want 60' clear spans and would prefer to be concrete (for durability of exposure to the nasty stuff of cars) and the paradox that cars are light, people are heavy--that is, we can design a parking deck to carry the live load of 1 car per 200sf (say, 40psf) while office buildings and residential corridors may want to support up to 100psf.  So you have to provide a beefier structure now to enable a potential higher live load 20 - 40 years from now)--more dollar cost and more carbon cost.

Other issues:

• Even "flat" parking areas usually need to slope to drain, which adds up to a lot of elevation change you'll have to fill in later. 
• You generally need a higher floor-to-floor height for the future uses than you do for an open-air structured parking deck now--and this in turn affects the slope of the ramps between floors at the future 'courtyard'; so either the client would have to accept a steeper slope than was their preference or a shallower mechanical system than their facilities people preferred.  Nobody likes to compromise...

We explored a bunch of different scenarios (see attached slides) but found that there was still a small carbon benefit to overbuilding the parking deck now--but a 10-15% first-cost premium, for a project that had already a signed fixed price contract in place.   Our compromise outcome was that we designed the adjacent deck to accommodate a future steel/timber office building on top, following the outline of Reynolds' proposal; the incremental cost of the foundations and main structure to accommodate this future building on top was small.      Takeaway:  You can design for the less-car future, but you either have to budget for it up front (as some municipal parking garages are willing to do) or be willing to give on some preferences around things like ramp slopes or mechanical systems.

For the Packard Foundation we worked with the city to approve drastic reductions to minimum parking requirements to eliminate underground parking. The key was landbanking surface parking that be converted if needed to structured parking if TDM plan was proven to not work. So there was required monitoring of parking levels for 5 years. Turned out: they met their commitments so all is well! The city, Los Altos,CA, applauded the creativity of the approach in the end. Brad Jacobson FAIA, LEED(r) AP, DBIA Partner Pier 1 The Embarcadero, Bay 2 San Francisco, CA 94111 +1 415-214-7276 [cid:G_190118_N24_webview_bb0303a9-c805-4097-ac97-3ab99950504f.jpg]

Jeremy, Thankfully it is commonplace in the locations we work to be reducing parking requirements more and more. Some urban projects now forgoing parking all together when a similar project would have required it just a few years ago. Parking transition is something that we assess in all projects of what does this space become if even less parking is needed in the future (either from autonomous vehicles, public transportation, shifts in working/living habits). How would you bring daylight into a subsurface parking level? How do you design height and structure to meet other uses (office, resi, retail)? We haven’t converted a parking structure yet but are definitely designing in flexibility to those being constructed today. It is part of the larger resilience and future risk reduction discussion we have with clients. Here is some work we did on autonomous vehicles that looked at future transitioning of parging structures/space. Autonomous Vehicles – Arrowstreet Kate _______________________________________ Katherine Bubriski, AIA CPHC, LEED AP BD+C, Fitwel Ambassador Director of Sustainability & Building Performance 617.666.7006 Direct Arrowstreet Fro

What a fabulous story. David Johnson, NCARB, AIA Principal (he / him) d: 510.480.4949 m: 415.987.7490 o: 503.445.7372 SERA 338 NW 5th Ave., Portland, OR 97209 Portland + Oakland seradesign.com