The
intersection of Walnut and Lake is within walking distance
from Cal-Tech and the trendy shops of historic Downtown
Pasadena, California. So, when Trammel Crowe Residential
of Costa Mesa began developing an entire city block
of luxury apartments, they knew they had a winner.
After all, the tenants could even watch the Tournament
of Roses Parade pass right under their balconies.
Experienced builders like Trammell
Crow understand the important of putting together
a good team. On large projects, the devil is in the
details, so when choosing a roofing contractor on this
project they worked closely with Lawrence Evensen,
President, All Style Roofing Specialists, Thousand
Oaks, California. "This project's staggered roof
design, building height and access offered a host of
challenges," said Evensen. "The owners of
the project insisted that we take extra precaution
to ensure a bulletproof, long life roof since access
to the roof areas after completion would be severely
limited due to the layout and location of the development." For
extra assistance Trammel Crowe brought in D7 Consultants,
Newport Beach, California, roofing and waterproofing
specialists, to work closely with All Style to approve
specifications, review bid documents, and provide continuous
on-site inspections. Issues such as building height,
foot traffic and tight mechanical equipment locations
made choosing the type of flat roof covering fairly
straightforward.
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| INSPECTION OF THE FINISHED ROOF ASSEMBLY. |
CertainTeed's Four-Ply (NB-N-B4) 20-year
NDL roofing system adapts well when installed on confined
or small roof areas. "Just to make the 4-ply system
a little more bulletproof, we kicked it up a notch
to a 5-ply (N-N-B5) built-up smooth surface roof over
a protective layer of rosin sheet," Evensen said.
And with the blessing of D7 and CertainTeed's Technical
Services group, the specification was written.
However, a much less obvious detail
remained. The Walnut Street project included 265 luxury
dwellings, and each apartment had central air conditioning.
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The locations of the
heat pump compressor units for each apartment were
rooftop mounted on platforms on the flat area of
the buildings. Each compressor unit had a pair of
copper tubes and one low voltage conduit that would
penetrate the structure through the newly installed
roof system membrane. The condenser tubes and wire
conduit, or "line sets", can be a prime source of
water intrusion inside a building. This problem is
complicated by the fact that one of the copper tubes
includes insulation, and water that gets inside the
insulation follows the tube like a highway through
the walls of the building, ultimately creating a
leaking apartment. The first floor apartments were
five stories below the roof decks, so a leak at ground
floor could create hard to identify long-term problems.
The line sets had to be waterproofed.
As a solution, All Style suggested
using their patented EPDM
Rubber Storm Collars. The
All Style three-hole line set collars isolate and waterproof
each of the three independent components of the line
sets, and secures them with a stainless steel hose
clamp. All Style demonstrated how effectively the line
set collars fit over the top of a standard lead pipe
jack, and explained the favorable economics of using
their simple storm collar system.
A plan was put in place to have each
line set enter the building through one 8 inch high
lead pipe flashing installed into the roof system following
standard CertainTeed construction details, CT-11 or
CT-12. Then, All Style's Line Set Storm Collars would
be installed by sliding the line sets into the pre-molded
nipples, and placing the Storm Collars over the already
installed lead flashings. A stainless steel hose clamp
on each of the three nipples would permanently secure
the Storm Collar to each flashing. Storm Collars create
the perfect counter flashing for lead pipes by creating
a waterproof umbrella, which keeps the water on the
roof.
"These Storm Collars are great. Let's
use them," said Joe Daniels, owner, D7 Consultants,
after the demonstration. "These are a simple solution
to a common problem we find on the roofs we work on."
Paying attention to the small details
of a roof project makes the difference between a successfully
waterproofed roof and a nightmare that keeps on giving.
After over six years, simple solutions like All Style's
Line Set Storm Collars have made the Walnut
Street Project a success story. The roof is watertight
and maintenance-free.
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