When Clark Roofing of
Waco, Texas, was selected to re-roof three McLennan County facilities in
downtown Waco, they knew there would be challenges. The roofs were all 35-plus
years old and leaked; one was notorious for ponding water. There was 95 tons of
gravel ballast to remove. Product deliveries would require navigating busy
streets, power lines and rooftop-mounted communication towers. The buildings’
historic features needed to be preserved.
What the crew could not have predicted were the added challenges
of working during the early weeks of the COVID-19 pandemic and during protests
for racial justice.
But attention to detail, determination, and a knack for finding
creative solutions are deeply engrained in the Clark Roofing culture. The crew
completed the work in just 20 working days, delivering new TPO roofing systems
that will stand up to the Texas heat and hail. Most important, everyone
remained safe.
The built-up roofing (BUR) systems on the McLennan County
Sheriff’s Office, the McLennan County Records Management building, and the
McLennan County Courthouse Annex were in rough shape. At 35 years old, 45-50
years old, and 45-50 years old respectively, each had significant leaks. They
remained structurally sound, however, so recovering them, rather full
tear-offs, was chosen.
Designed to Take What Texas Dishes Out
Waco is in “Hail Alley,” and average high temperatures top 90
degrees Fahrenheit from mid-June until mid-September. To create roofing systems
that would withstand those conditions over the long haul and receive the
desired 30-year no-dollar-limit system warranties, Clark Roofing looked to
their go-to single-ply roofing system — 80-mil-thick standard TPO in white,
fully adhered.
Nearly
400 squares of TPO from Mule-Hide Products Co. was
installed on the three buildings.
“In our experience, the thicker TPO is by far the best option in
terms of durability and getting hail ratings and FM Global coverage,” says
Clark Roofing General Manager Mike Anderson. “TPO can handle the Texas heat.”
The fully adhered systems also will withstand the hailstorms Waco
experiences every year better than mechanically attached system would.
“If a large piece of hail strikes a plate or screw, it can damage
the membrane,” Anderson explains. “With full adhesion, you’re only using
fasteners on the perimeter to meet wind uplift or FM Global requirements.”
Full adhesion costs 10 percent to 20 percent more than mechanical
attachment, but given the pounding that Texas roofs take, it is an investment
that will be recouped in roofing system durability and longer lifespan,
according to Anderson.
The key is the wrinkle-free installation that full adhesion
provides. “To withstand hail, the roof needs to be very tight,” Anderson says.
“If there are places where the membrane isn’t touching the substrate, hail has
a better chance of puncturing it. You’re also less likely to have ponding water
when the membrane is wrinkle-free.”
TPO Bonding Adhesive from Mule-Hide Products was used to adhere
the membranes. “Solvent-based adhesives flash off faster than water-based
adhesives, deliver a stronger bond, and can be used on cooler days,” Anderson
says.
In each roofing system, a single layer of 1.5-inch-thick Mule-Hide
Poly ISO Flat insulation was used as a top layer insulation and a separation
board. The insulation was adhered using Helix Max Low-Rise Adhesive from
Mule-Hide Products.
Heavy Lifting
But before the new roofing systems could be installed, 95 tons of
gravel ballast had to be removed. To ensure proper adhesion of the adhesive,
the substrate must be clean and dry before the adhesive is applied. Many
contractors would have simply shoveled the gravel off, filling three dumpsters,
and called it a day.
From their previous, off-the-jobsite experimentation, the Clark
Roofing crew knew that extra attention paid to surface preparation would result
in a stronger bond. So, after shoveling, they swept the surfaces with a
motorized broom and blew away the remaining dust, filling 19 dumpsters.
All three rooftops were ballast-free and clean before installation
of the first new roofing system began, ensuring that crew members cleaning one
roof section did not track dirt onto newly installed TPO.
It took nearly two full days to complete the clean-up, but it paid
off in a tight bond between the insulation and the substrate.
Eliminating Problems
The roof of the Sheriff’s Office building had been plagued by
ponding water for years. The original project specifications called for using
tapered insulation to remove the water. But Clark Roofing had another solution
that cost approximately $40,000 less to implement. Six TPO-clad troughs — 12
inches wide and 200 feet long — were instead installed, each connecting to
scupper outlets on the building’s perimeter to direct the water off the roof.
The roof of the Courthouse Annex building was littered with 40
obsolete, damaged or torn-off penetrations for exhaust fans, sewer fans and
air-conditioning units. They created an obstacle course and were the source of
many of the roof’s leaks.
The crew removed the penetrations, along with miles of unneeded
conduit and wire, reducing the potential for future leaks and making navigating
the rooftop far easier.
“When we started, you couldn’t walk 3 feet without bumping into
something,” Anderson says. “Now you can go 10 or 15 feet without any trouble.”
Preserving History
The Records Management building, constructed in 1916 for the Texas
Telephone Co. and expanded in the early 1950s, is an architecturally
significant fixture in downtown Waco. One of its signature features is its clay
tile parapet walls.
Following the standard practice of installing wood blocking, then
plywood, and finally the TPO membranes would have taken away from the
building’s historic look. So, the Clark Roofing crew stopped the TPO membranes
short of the parapet caps and terminated them inside the walls, out of sight
from the street. They then refilled the joints and applied Foxfire Matrix Pro
SS-WB for waterproofing. The roof was watertight, with the building’s character
preserved.
Challenging Roof Access
Busy streets and the presence of high-voltage power lines made
material deliveries challenging at all three buildings. Crews blocked off
streets as necessary, working quickly to minimize disruptions. Many deliveries
were scheduled at night or on weekends when traffic was lighter.
Deliveries at the Courthouse Annex required flawless communication
between the crane operator and roofing crew. There was only a 15-foot area in
which to work. Communication towers used by the Sheriff’s department and other
county agencies are located on the building’s roof, anchored by big guidewires.
The building’s parapet wall is 5 feet high.
The crane operator could not rely on visual signals from crew
members on the rooftop to direct him, as he could not see them over the wall.
So, they used two-way radios, with crew members verbally guiding the crane
operator inch by inch.
“You have to really trust someone to do that,” Anderson says. “He
was spot-on.”
Early Days of COVID-19
The COVID-19 pandemic arrived just as the projects were beginning.
But the roofs had been leaking for months, so there was no thought of
postponing the work.
A variety of protocols were followed to keep everyone safe,
including:
A supervisor was always
on the jobsite for quality control and safety. Sometimes two were there — one
on the ground and one on the roof.
All meetings were
conducted virtually.
To avoid going inside
the buildings, crew members rode a manlift to the rooftops. It took a full hour
to get the eight- to 12-person team in place, adding a full day to the job.
All crew members wore
face coverings, safety goggles and disposable gloves and regularly sanitized
their hands. The crew went through as many as 200 disposable facemasks each
week, and gaiters reminded them not to touch their faces.
Social distancing was
practiced. “We don’t even think about staying 6 feet apart anymore,” Andersons
says. “It’s automatic.”
Hand tools were not
shared. If equipment, such as welders, needed to be shared, it was sanitized
before changing hands.
Crew members had their
temperature taken multiple times a day, and anyone found to be running warm was
required to get a COVID-19 test.
Disposable water cups
were provided. No bottles or cans were allowed on the roofs.
At lunchtime, crew
members left the roof and cleaned up before eating.
The precautions worked. There were no known cases of COVID-19
among the crew.
Protests for Racial Justice
Sheriff’s deputies shut down the Courthouse Annex jobsite on three
occasions, having received word that protesters for racial justice were
planning to assemble outside the building. The crew was ordered to get off the
roof. Anything that could be used to cause injury or damage property — from
sharp tools to the Sky Trak — was removed from the jobsite.
On one occasion, the crew had just removed the exhaust fans from
the roof. Anderson says, “We told the deputies, ‘There are 3-foot openings in
the roof. If it rains, the building will flood.’ They said, ‘Get off the roof.
If it leaks, it leaks; we’ll take responsibility.’ Luckily, it didn’t rain.”
Thankfully, the protests were peaceful, with no injuries and no
damage to property. The shutdowns ranged in length from one to three days and
delayed completion of the job by four or five days.
Three roofs. Twenty working days. Four hundred squares of new
hail-resistant TPO roofing installed. Challenges — from the expected to the
unforeseeable — overcome. No leaks during the active hail season that followed.
Just another day at the office for the Clark Roofing team.
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