On June 24th I wrote a detailed letter to the City of Berkeley's Building Department, City Manager and City Solicitor regarding their memorandum of proposed changes to the Cities Building Codes.
They want to implement various changes related to the construction of and methods of waterproofing balconies, along with requiring inspections of decks and balconies on apartment complexes and condominiums, While their proposed changes are well intentioned, some of them are a little crazy in my opinion.
My biggest objection is having Architects, General Contractors and Pest Control Technicians inspecting decks...why do I say that?
Read my letter and leave a comment telling me what you think!
June 24, 2015
City of Berkeley
Mr.
Eric
Angstadt, Christine
Daniel, Zach Cowan
Building &
Safety Department
2120 Milvia Street
Berkeley CA 94704
Dear Mr. Angstadt,
Ms Daniel and Mr Cowan,
Let me first say
that I am deeply sorry and anguished over the tragedy that occurred
last week with the deaths and injuries to thirteen people. I cannot
fathom the sorrow that the bereaved parents and families must be
experiencing.
My background
includes six years as an estimator/sales person for several large
deck waterproofing companies doing business in the San
Diego/LA/Orange County/Ventura/San Luis Obispo areas, as well as
being a CSLB licensed (currently inactive) waterproofing contractor
for seven years. I am now a consultant and perform deck inspections
for real estate transactions and for HOA's. I have sold and installed
hundreds of thousands of square feet of deck systems in my career.
I have been one of
the experts used by several media sources for comments and opinions
on the causes of the deck failure. As owner of DeckExpert.com I
promote the use of Pedestrian Traffic Coatings at our website of the
same name for use on balconies, stairs, roof decks and walkways.
Pedestrian Traffic Coatings are walkable waterproof membranes
typically used on decks, stairs and balconies covered with plywood
decking and these are also listed and evaluated as roof assemblies
for low slope roofs. These membranes are listed in ICC-ES' website
under Division Seven Thermal and Moisture protection under 07 18 13.
I would like to
take a few moments of your time to lay out my recommendations that
the City of Berkeley should consider implementing to avoid another
tragedy in the future. I understand that there are several
recommendations already in the works, and I would hope you will
consider incorporating my recommendations as well.
As you know
already, the deck that failed appeared to have a Grace 3000 bituthene
membrane as it's waterproofing, covered with a topping slab of
concrete. Basically this is the same as a plaza deck, found over
below grade parking structures with the living units built using wood
framed construction. These plaza type decks must be carefully
assembled as once covered with a topping slab, the waterproofing is
impossible to inspect or repair without removal of the topping slab.
Plaza decks must have a subsurface drain system in place to deal with
water that is bound to get under the topping slab.
Plaza decks in my
opinion and experience have had many problems with their assemblies
in the past, due to the technical skill necessary and the usual lack
of skilled labor who understands how to assemble them. I believe that
these types of assemblies should be banned from use on top of wood
framed and plywood covered decks.
In lieu of
plaza deck assemblies, I would instead propose that the City of
Berkeley consider implementing a requirement that only pedestrian
traffic coatings be used on plywood covered decks. The main reason
for this is that pedestrian traffic coatings are “an all in one”
solution to waterproofing these decks while providing a walkable
surface at the same time. They can be easily inspected and are
relatively easy to repair if damaged. Most Division Seven Pedestrian
Traffic Coatings are also Class A roof rated systems (ASTM E-108)
and many are also rated as One Hour assemblies (ASTM E-119),
therefore meeting the Cities fire resistant requirements. Many of
these systems can be finished in any number of ways with texture and
pigmented sealer as well as stained/stamped etc to look like tile,
stone, wood etc. There are several different system types available,
leaving architects and specifiers choices among concrete based
coatings, liquid applied coating, slip sheet systems and sheet
goods. Concrete and many of these coatings can also be used to
correct deficient slope conditions, so achieving a 1/4” slope per
foot is very easy to do on flat decks that were not framed with
slope in them.
In regards to
the Berkeley Building Code changes proposed, I concur with the
recommendation to require Ventilation of weather exposed enclosed
assemblies under Section 1203.6. Most of our manufacturer's already
require this in their general requirements in their CSI
specifications. I also concur with the inclusion of access panels on
the underside for inspection of the framing.
In regards to
adding Section 1404.13 Projections exposed to weather, after
consideration, I concur with using pressure treated wood or steel
for framing the deck. I do believe that properly waterproofed,
conventional douglas fir framing is perfectly suitable for the
framing, however, rot resistant materials will certainly perform
better if exposed to water over a longer period of time.
Under Section
2304.11.4.2 Wood structural members, I propose that the City
eliminate the use of moisture permeable floors or roofs such as
concrete or masonry slabs. My reasoning is that these types of
assemblies trap water in them and as they are typically part of a
plaza type deck system, are not conducive to using them on balconies
covered in plywood anyway.
Regarding
adding Section 601.4 Structural Maintenance; I concur with requiring
inspections. I have several changes to propose; these being
requiring inspections every two years instead of the proposed five
year interval. In my experience as a waterproofing contractor and
consultant, five years is to long between inspections. A lot of
serious damage can occur in a short time. Manufacturer's of
Pedestrian Traffic Coatings require as part of their warranty that
their systems be inspected yearly. Regarding who should inspect the
decks-waterproofing is a specialty trade. In my work as an educator,
I usually have a room full of people where 90% or more are general
contractors. General contractors are just that, generalists. I've
found in my experience that most do not understand waterproofing in
general and decks in particular. While structural pest control
licensees know the signs of dry-rot, wood destroying organism
infestations etc, they do not understand waterproofing either.
Engineers and architects are generally familiar with waterproofing
concepts and can certainly recognize inherent defects and issues
with contiguous building materials and would be suitable candidates
to perform inspections. I believe the best candidates to perform
deck waterproofing inspections are waterproofing consultants. As a
group, we are very familiar with installing and maintaining
waterproofed decks and balconies. It may sound self-serving and I
appreciate anyone thinking that it is, however, as an example, I've
spent nearly 14 years as an estimator and owner and applicator of a
firm specializing in waterproof deck installations. I've found that
many of my peers were applicators and as we “age” out of being
able to work on our hands and knees we seem to transition into
consulting and inspecting. The Roof Consultants Institute (RCI) and
Sealant Waterproofing Roofing Institute (SWRI) are two organizations
that are focused on roofs, decks and waterproofing systems and are
probably best qualified to do such inspections. We have familiarity
with general building requirements and understand the importance of
contiguous building materials needing to be weather resistant as
well.
I would
suggest that the City add the following requirements for deck
waterproofing; these being that building inspectors begin inspecting
the waterproofing of the decks as it's being installed, including
inspecting the flashing system and substrate prior to covering with
a membrane. Most importantly, inspectors should verify that the deck
is sloped or tag the deck so that it will be sloped and they can
check the slope before signing off and allowing finish coats to be
installed. Once the membrane is installed, but before it is
decoratively finished, it be inspected again. As part of the
requirements, the City should allow only ICC-ES pedestrian traffic
coatings with Class A ratings minimum and One Hour where already
required. The ICC-ES report should be made part of the submittal for
building permit approvals.
Regarding
substrate-the use of Oriented Strand Board (OSB) for pedestrian
traffic coatings is not accepted by ICC-ES nor any manufacturer. All
fire testing is performed using plywood only. OSB, in my experience,
despite the claims by manufacturer's that it's better at water
resistance, is a sponge. I've seen OSB expand and it doesn't return
to it's original dimensions. Therefore, OSB should be banned for use
on decks and plywood be the only acceptable substrate allowed. I
would caution against requiring pressure treated plywood, mechanical
fasteners used on some systems may not be compatible and liquid
applied coatings may have issues as well with compatibility.
Regarding
railings-steel/aluminum railings that mount onto the deck should be
banned. In my experience I've found that it is impossible to
guarantee a waterproof deck won't leak when railings penetrate the
waterproofing. Only metal railings that mount to the fascia should
be allowed. Wood 4x4 posts penetrating through the plywood and
bolted to the deck framing can be flashed and waterproofed. The key
in waterproofing these wood posts is that they MUST be wrapped with
bituthene/Tyvek/building paper and then either boxed in for a final
finish or a post sleeve, typically made of plastic/synthetic
materials is slipped over and finished on top with a decorative “hip
roof” style cap to shed water.
As a general note,
it is contained within the CBC 1998 code 1402.2 that openings in
exterior walls are required to be flashed in such a manner as to make
the opening weatherproof. For waterproofing purposes on decks, metal
flashings, be they galvanized steel, copper or stainless steel, are
meant for the purpose of terminating our coatings to. All deck
waterproofing systems must be run up the vertical leg of the flashing
so that contiguous building materials are installed down over the
flashing, forming a weather resistant barrier. Counter-flashings, be
they Z bar or weep screed for stucco provide the mechanism for water
to be shed off and away from the buildings interior.
Furthermore, as a
general note, building inspectors and the building department must
ensure that proper weather resistant barriers meant to waterproof the
decks, the building and the foundation are specified and installed
properly. These systems are just as, if not more important to long
term comfort, use and enjoyment of the building than framing,
mechanical and electrical systems. Inspectors should be required to
closely inspect all weather resistant barriers, including siding,
windows, doors, foundation waterproofing and the decks and roofs to
ensure they meet or exceed code requirements.
I sincerely
appreciate your concern in wanting to strengthen and improve building
codes and requirements for the safety and security of occupants. I
hope these recommendations will be considered and implemented. I am
willing and able to appear in front of any panel, council meeting or
with the building departments staff to discuss these recommendations.
Please let me know if you would like me to appear to testify/discuss.
Sincerely,
William Leys
