The California Building Code (CBC) impacts housing development in San Francisco and across the state. Updates to the CBC occur every three years, and these changes can dramatically impact our approach to future projects. The City of San Francisco has significant amendments to the code, particularly relating to the Green Building Ordinance. State building codes and local amendments have a strong influence on why San Francisco is the most expensive place to build housing in the country.
In order to better understand these changes, the San Francisco Housing Action Coalition (SFHAC) recently hosted Jeff Brink from DCI Engineers and Paul McGrath from MEYERS + Engineers. Jeff and Paul walked SFHAC’s Regulatory Committee through the 2016 CBC to highlight recent updates to the state code, as well as San Francisco amendments, to illustrate what we can expect going forward.
Two notable changes involve allowable building height and area limits. The presenters displayed a table comparing current building code requirements for Type III buildings to show how increases in a both a building’s height and total floor area had been achievable by fully sprinkling a building under the prior code.
However the 2016 update no longer allows for both height and area “bonuses” for a fully-sprinkled building – it is either/or. However, the overall area of a Type III building permissible under the new code has increased, but without an additional height increase. Given the greater area possibilities under the new code, this triggers consideration of “fire walls” – the updated code now allows for collapse of either side of the wall without posing a risk to the structural integrity.
One of the more exciting 2016 CBC updates has to do with wood frame buildings, following up on our previous discussion of Mass Timber. Under the 2013 CBC, a five over one building (five stories of wood over one story of concrete) was the maximum allowable under 85 foot height limits. The 2016 CBC now stipulates that concrete isn’t limited to one floor and the building can be a five over three (or a six over one) configuration.
Structurally, the most interesting aspect is not the 2016 changes, but rather what we can be expecting from the 2019 CBC updates that will be implemented for buildings in 2020 and beyond. The conversation will continue around Cross-Laminated-Timber plus the implementation and improvements to the 2016 CBC updates.
CALGreen has updated its requirements for electric vehicle parking spots of between 4% and 10% of the spots for any commercial portion of a housing project. The 3% remains in place for the residential parking spot (Stay tuned for stronger requirements for San Francisco).
Developers should consider how to address capacity for the anticipated proliferation of Electric Vehicles (EV), which are expected to account for 25% of vehicles on the road worldwide by 2030, which is only a decade down the road from when projects currently being designed will open. Could this percentage be double the 25% in the Bay Area?
Installing this capacity now will have major cost impacts with increased PG&E service size. It’s perhaps better to install the minimum now; and operate the building for a few years: which will allow enough time to collect measured electrical load date. A sensible loophole in the NEC allows us to use this data to demonstrate that additional EV stations can be installed within the building’s existing utility service capacity.
Mechanically, the CMC requires that residential kitchen exhaust, toilet exhaust and dryer exhaust run in separate ducts (it used to be possible to combine kitchen and toilet exhaust, to save a riser). San Francisco takes this a step further, and insists that all ranges have a ducted kitchen hood: re-circ hoods have gone the way of the dodo.
The Energy Code (Title 24, Part 6) insists on Commissioning on buildings 3 stories and larger (if >10,000 SF). It also now encourages windows and doors to have interlocks which will shut down (or do temperature reset) on the AC or heating in the units when they are open for more than five minutes. It’s possible to avoid the expense of the several hundred dollars to do this per unit; but this will result in a hit to your performance energy model to the tune of up to ~5% that will need to be compensated elsewhere.
While the state code provides for solar ready buildings, where buildings ten stories and under must allow 15% of the roof (including any podium) for future installation of solar photovoltaic (PV) electricity) or solar thermal (hot water); San Francisco’s Better Roofs Ordinance requires that the solar be built-out on day-1. Allow $6- $10/SF for your total roof area. The Ordinance allows for 30% of the roof area as green roof to be substituted for the 15% solar build-out; but this will not often be seen as a practical solution, as you will still need to allow for the 15% of the area for future. How many buildings, especially tall ones, can set aside 45% of the roof area for solar / green roofs?
The good news is that the new codes will result in buildings that allow people to live longer and happier lives. The bad news, aside from the potential structural benefits allowing for increased use of wood frame, is that many of the other changes will cost more money. Construction costs in the most expensive market in the country keep rising, and the challenge of providing affordable housing gets harder.
If you have any questions for Paul (paul@meyersplus.com) or Jeff (jbrink@dci-engineers.com), feel free to reach out.
