Kerwin Lee, AIA, CASp
It has been over two years since the tragic balcony collapse in Berkeley. The city reacted by creating their own ordinance to address the issues, mainly focusing on maintenance. The state has enacted their own Emergency Amendment to the code, which was enacted at the end of January of this year for a 18-month period. The Building Standards Commission has extended the Emergency Amendment.
The requirements, which amends Part two of the Title 24 and Part ten for existing buildings, has three main points:
- Waterproofing documentation
- Ventilation of concealed spaces, and
Details of the code requirements can be found in Bulletin 17-01, Dated February 2, 2017 from the Building Standards Commission at: https://www.documents.dgs.ca.gov/bsc/Info-Bulletins/BSC_Bulletin_17-01_FINAL.pdf
Let’s start with “Maintenance.” This responsibility falls on the local jurisdiction as to how to implement this. When the city of Berkeley looked at this, it was estimated that 6,000 letters would be sent of building owners. Each local jurisdiction will deal with this as they see fit.
Item 2 “Ventilation” is new to the code. The code currently does not address, require or is silent on the issue of ventilation for enclosed balconies or other types of projections. Ventilation is generally associated with moisture with condensation related to a temperature difference between spaces. Although the code addresses keeping moisture (weather protection) out of these areas, the basic assumption of the new section is that if there is moisture within these assembles, the ventilation will help mitigate the problem. The addition of ventilation will also provide visual opportunity to inspect the enclosed or sealed off areas more easily. The alternative is to provide access panels or performing destructive demolition for inspection and repairs. So the venting in the ordinance is different from venting in the current code.
The addition of the vents may address one issue, but may also create another issue related to fire protection of the structure. All new R-1 and R-2 structures are required to be fire resistive in design, Type A construction. This would include projections, like decks and balconies. These projections are considered floor or floor/roof assemblies and required to have the same fire resistance as the rest of the building. By adding all of these vents, which is required in the ordinance to be a minimum 1/150th of the area of the space ventilated, this may compromise the fire resistance integrity of the balcony. For an 8 x 10 foot deck, a minimum of about 77 square inches of venting is required. This is potentially a lot of unprotected openings.
Item #1 “Documentation” has a big effect on how drawings are created. The code change requires designers to show the waterproofing associated with the types of exterior elevated elements. First of all how many designers are competent with waterproofing? One can find many details for roofing, decking and opening protections, but what happens when these elements are joined together? What happens when a door opens on to a balcony or deck? Now we have a door opening intersecting a balcony, a horizontal element. This can be a very complicated detail for waterproofing. Perhaps the code change addresses this by requiring venting and physical inspection, with the assumption of waterproofing failure. This issue could be a big responsibility and liability for the designer.
Comments from Steve Winkel, FAIA
I cannot comment in detail on what the CBSC Exterior Elevated Element (EEE) subcommittee will recommend, as we are in the midst of developing those recommendations. But Kerwin’s comments are all spot-on. The issue of documentation is one where architects who do not consider themselves adept at specifying and detailing deck waterproofing may need to seek expert consulting advice. They also need to be very aware that these issues involve intersections of multiple systems of walls, doors, windows and decks where there are transitions between waterproofing elements, all of which can lead to failures to prevent water intrusion. The one issue Kerwin did not mention was about increased requirements in the new provisions for inspections prior to enclosing deck elements. Designers should consider inclusion of special inspection provisions for decks and balconies under the provisions of CBC Chapter 17.