Private Residence, San Francisco
As
locations go, this private residence certainly has one of the most
sought-after zip codes in San Francisco! Sitting directly across from
the St Francis Yacht Club on Marina Boulevard, this luxury property now
boasts a stunning multi-level 1200 square foot roof terrace, offering
breathtaking waterfront views. Designed by ODS Architecture, based in the San Francisco Bay area, the roof terrace offers a glorious outdoor space, whilst the Glazing Vision Flushglaze walk-on rooflights,
imported specially from the UK, and interspersed in the decking, ensure
that the bedroom suite floor below is bathed in diffused daylight.
Structural challenges of adding a roof terrace to this period property
Built
in the 1920’s in the Spanish Mission style, this 3-storey property
already offered an impressive 4000 square feet of space, but the
homeowner wished to extend the house further, particularly looking to
unlock the potential of the unused, run-down flat roof by adding a
fully-operational outdoor kitchen as well as spacious dining and living
areas. A viewing platform to take advantage of the views out over the
marina was also on his wish list.
ODS Architecture was appointed
by the homeowner in 2012 to undertake this ambitious project. Renowned
for their contemporary approach to residential design, this project was,
however, a new departure for the team at ODS – taking a traditional
house and adding a modern twist to it. The brief to build a stylish roof
terrace as well as to reconfigure the master bedroom floor posed a
number of significant structural challenges. Firstly, changes to the
historic façade of the property were not allowed by the State of
California, plus any new construction had to be out of view of the
street as much as possible. Furthermore, the close proximity of the
neighbours’ houses on both sides compromised the amount of natural light
entering the client’s home, and the inability to install windows
because of insufficient clearance to the property line meant a regular
upper floor extension in a traditional masonry sense was not going to be
appropriate. Building a roof terrace,
or deck, is never an easy task but at Marina Boulevard, this was going
to be particularly challenging as the silver-painted rooftop was in a
state of disrepair.
ODS’s innovative design for a new multi-level,
multi-functional roof terrace, incorporating a modernization of the
third floor of the house, demanded highly creative construction
techniques. General building contractor, Jeff King & Company, working in close collaboration with ODS,
re-framed the roof with new wooden supports, metal connectors and
hardware to ensure that it could take the weight of the planned roof
terrace. Vertical cables on the side of the house were made to fit.
Large roof terraces
always require careful attention to waterproofing, and at Marina
Boulevard, where old and new systems needed to be finely tuned in order
to create a completely waterproof envelope, a high-tech waterproof
system had to be devised. Additionally, the deck was laid with durable
chip-, fade- and crack-resistant porcelain tiles that could be easily
removed and replaced should there be a leak, or water damage in the
future. They are also fireproof, an important feature given the type of
appliances installed on the roof terrace and the closeness of the
neighbouring properties to either side.
Multi-level layout for roof terrace design
The
lower tier of the roof terrace contains the impressive outdoor kitchen,
resplendent with stainless steel Viking appliances and concrete counter
tops, which are a nod to the stucco plaster walls of the old house. The
dining area, complete with a large dining table, is adjacent to the
kitchen and on the next tier there is small bar and a fire pit for
alfresco entertaining. The “crow’s nest”, the viewing platform, is
reached by a glass and timber stairwell, and was created by the contractor
where the original roof was sloped. This level deck, based on a
pedestal system that reaches up to 24 inches, is split into 4 quadrants
to ensure proper drainage and is waterproofed to protect the sitting
room below, which is accessed from both the master bedroom and the main
deck. This room provides a contemporary, yet intimate space in which to
relax and retreat should the weather prove inclement. It can be closed
off by glazed sliding doors yet it is bright and airy, and offers a
quiet peaceful zone to observe the marina.
Unlocking daylight to living space below the roof terrace
A key consideration, however, for the architects and contractor in the design of the roof terrace was the need to unlock the daylight
to the lower bedroom & bathroom suite floor, whilst simultaneously
protecting the privacy of these intimate quarters. The original roof had
4 square-shaped skylights, which had allowed for natural light to enter
the living space below. As the old roof was being covered with the new
roof deck, and the old skylights removed, a glazing solution was
required that would guarantee a direct source of daylight, and could
utilise the original skylight apertures. Additionally, the glazing had
to be sufficiently robust to be walk-able so as to not compromise the
structure or the practicality of the deck itself, and it had to be able
cope with inclement weather conditions, including heavy rainfall. Safety
too was a critical factor in the selection of the glazing – it had to
be safe underfoot.
After extensive research ODS specified a series of Flushglaze walk-on rooflights,
manufactured in England by Glazing Vision, a highly respected and
innovative glazing specialist producing high-quality rooflights for the
residential and commercial markets both in the UK and overseas. Unlike
skylight products available in the USA, the Glazing Vision Flushglaze
rooflights were designed and tested to withstand heavy foot traffic
whilst maintaining watertight integrity. Architect, contractor and
client all felt that these rooflights best met their exacting criteria.
The Flushglaze walk-on rooflights
had the advantage of being able to be installed flush with the
porcelain floor tiles used on the main roof terrace, making for a
perfectly flat surface. A lack of any visible internal framework meant
that, crucially, these rooflights would not spoil the visual effect – on
the contrary they would enhance the contemporary appearance of the roof
terrace, adding a distinct wow factor.
Safety & privacy considerations
For
the three rooflights located on the main deck the glazing had been
specifically ordered with a sandblasted finish. This would result in a
more diffused light entering the bedroom suite below, but would also
improve obscurity, thereby offering greater privacy too, an important
factor for the client given that the roof terrace would be used
frequently for entertaining guests.
Additionally, the sandblasted finish
provided better slip-resistance than standard glazing. Slip resistance
is measured using mean Pendulum Test Values (PTV), with values of 25-35
deemed as having moderate slip risk and 36+ as a low slip risk. Glazing
Vision’s sandblasted glass achieves a PTV of 50 as standard, well above
the threshold of PTV 36 to be categorized as having a low-slip
potential, and it was considered ideal for use at Marina Boulevard.
“Crow’s nest” at the top of the house
The
fourth of the Glazing Vision Flushglaze walk-on rooflights, and the
largest at 67 x 34 inches, was installed on the viewing platform, and
unlike the other 3 rooflights, its glazing had a fritted finish. A
screen-printed frit, that included particles within the ink to create a
rough texture, was applied to the glass in a unique pattern to provide
40% coverage, significantly increasing the slip resistance of the glass.
Indeed, fritted glass generally achieves a PTV of 60, thus providing an
even better slip resistance than the sandblasted.
The generous size of the Glazing Vision Flushglaze walk-on rooflight
on the viewing platform also ensured that daylight flooded the narrow
walkway underneath, from which the adjacent master bedroom sitting room
also benefited. Complimenting the contemporary staircase leading up from
the main deck, this almost frameless rooflight stylishly combined with
the IPE wood flooring to create a kind of nautical feel, a perfect
environment from where to watch the Americas Cup race!
Whilst this challenging project took 2 ½ years to complete, the resulting roof terrace is testament to extraordinary teamwork. Indeed, as the contractor, Jeff King & Co.
explains, it was the result of the client, architect and contractor
“working collaboratively to understand the design intent and to make
sure that the craftsmanship realized the dream”. And, importantly for
the State of California, this modern roof terrace is neither visible
from the street, nor does it detract from the historic character of the
neighbourhood. The success of this build earned Jeff King & Co. the
2016 Contractor of the Year award (Landscape design/outdoor living).
The
roof terrace design is convincing in its simplicity, and the
sensitivity to colour and materiality ensures it blends seamlessly with
the rest of the house, so that when walking into the living space on the
master suite floor, as Alan Ohashi of ODS proudly states, “one has the
feeling that nothing had really happened” above. Architecture at its
finest!
To find out more about design considerations for roof terraces you can download our latest guide.
