Roofing contractors in Texas and Oklahoma are accustomed to seeing roofs ravaged by frozen rain. “We work in what is referred to as the ‘Hail Belt.’ That being said, many roofing companies around the country have office sites in Dallas or other major cities in Texas and Oklahoma. Hail damage is a very real concern for building owners and should be dealt with as soon as possible,” said Robert Norrell of Galt Construction.
He and his crew were recently called to
the scene of the Nelson Wholesale Ag Mart and Nelson Storage Units in Brownwood,
Texas, where they found roof
areas that were damaged by hail ranging in size from one-and-a-half to
two-and-a-half inches (3.8–6.4 cm)! According to Norrell, when hail hits a
metal roof, it can create pits in the substrate. These pits collect dirt, water,
and debris and are subject to corroding much more quickly and easily than the
rest of the roof. “Hail that hits the edge of a roof can break the metal
substrate, and any coating that exists on the roof can also be damaged,”
Assessing the Damage
for the Harkey Family Trust, owner of both businesses, although the damage was
moderate to severe in some areas, it was not necessary to replace the roofs of
the wholesale mart and the storage units. “It was decided that it would save a
tremendous amount of time and money to recoat the roofs. This was a much better
option than ripping off the existing substrate and installing brand new metal
roofs,” stated Norrell. The Galt team was tasked with applying an American
WeatherStar Met-A-Gard coating system on 184,568 square feet (17,146.9 m2) of
Met-A-Gard is a fluid-applied acrylic roofing system
consisting of butyl tape and American WeatherStar’s Acrylic 211 basecoat and
topcoat. The system has a 10-year warranty and is designed to restore and
protect metal roofs by forming a watertight seal and preventing rust, therefore
extending the life expectancy of the roof. In addition, Met-A-Gard uses cool
roof technology to substantially reduce heating and cooling costs.
First on the Agenda
With the specifications and scope of work nailed
down, the crew got to work on the approximately 100,000-square-foot (9,290.3 m²)
Nelson Wholesale Ag Mart. “Although the buildings are on the same property lot,
the work had to be done at different times because of the separate insurance
claims that were filed for each business. We started with the Ag Mart, which
took two weeks to complete. Then we got to work on the storage units, which
followed the same process as the Ag Mart and also took two weeks from start to
finish,” said Norrell.
The first order of business for the team,
which ranged in size between six and eight members, was to power wash the
24-gauge metal R-panel galvanized Purlin Bearing Rib (PBR) substrate. Using a
3,500 psi (24.1 MPa) pressure washer, the crew cleaned the entire roof to rid
the surface of any dirt, debris, and other contaminants. Once the substrate was
properly cleaned, Norrell and his crew made sure all screws in the metal roof
were sound and tight. At that point, it
was time to hand-lay the butyl tape over every vertical and horizontal seam.
“One side of the butyl tape is sticky and adheres to the metal substrate. The
other side is a polyester fabric that bridges the gap in the seams and gives
the coating something to grab onto,” stated Norrell.
the seams taped, the roof was ready for the application of the Met-A-Gard
coating system. However, there was just one element holding them back: the
to Norrell, Brownwood,
Texas, is known for its extreme
temperatures. “When it’s hot, it’s really hot and when it’s cold, it is very
cold and often windy. This project took place during the winter months, so we
were constantly monitoring the temperature to make sure that it wasn’t too cold
to apply the coating,” said Norrell. Cold temperatures affect the cure rate of
the coating system and may cause the different layers of the system to cure
unevenly. For example, while the top layer may appear to be fully cured, the
layer underneath may not be completely dry. This situation can lead to
buckling, pitting, cracking, and, ultimately, premature coatings failure.
“There were several days when the temperature dipped too low and we couldn’t
apply the coating system,” revealed Norrell.
addition, work was put on hold during the windiest days, as the possibility of
overspray was too great for the crew to continue coating application.
A Is for Acrylic
Weather difficulties notwithstanding, the
Galt crew kept on schedule. First, they
brush-applied Acrylic 211 over all screws and seams at an average dry film
thickness of 80 mils (2,032.0 microns). Then, using Graco 733 and 833 spray
rigs, the crew applied Acrylic 211 over the entire roof area. They spray-applied
the coating in two passes for an approximate final thickness of 24 dry mils
(609.6 microns). “The first layer was a different hue than the second layer, so
we were easily able to find any low spots,” said Norrell.
Acrylic 211 is an acrylic elastomeric coating
that combines high solids emulsion polymers and biocides to provide durability,
reflectivity, weatherproofing, and mildew resistance. It also reduces the daily
expansion and contraction (aka thermal cycling) of roof substrates. According
to Norrell, acrylic products such as American WeatherStar’s Acrylic 211 are an
excellent choice for pitched roofs that are not prone to the collection of
That same roof pitch that made acrylic an
excellent coating system material choice also meant that fall protection was a
must for the crew. “The project was on multiple levels with skylights
everywhere. We used Shock Wave 2 lanyards and iSafe Intelligent Safety Systems
both made by DBI SALA. Every crew member was hooked up and tied off the moment
they got on the roof,” stated Norrell. The crew also wore long sleeves, long
pants, steel-toed boots, gloves, goggles, and hard hats. Flags and cones were
set up in the parking lot to mark the working area and to ensure public safety,
as well as avoid issues with overspray on parked cars.
After four weeks total of working time,
the Galt Construction crew completed the roof recoat for both the Nelson Ag
Mart and Nelson Storage Units. “We are pleased with the outcome of this job,
even if the weather was a bit of a wild card. The Harkey Family Trust can be
assured that the roofs of these buildings are protected and will stand up to
the extreme weather conditions that are common in Brownwood,” said Norrell.