REGIONAL_ NEWS First-Hand Experience with Cold Weather Roofing

REGIONAL_ NEWS
First-Hand Experience with Cold Weather Roofing

January 19, 1996 • Minneapolis, Minnesota
Thomas Hutchinson, AIA, RRC • Director, Region Three
Thomas Hutchinson, AIA, RRC
The design and application of
roofing systems in cold
weather were appropriate
themes for Region Three’s
winter meeting. Almost 50 people
braved temperatures as low as 23
degrees below zero (-55 wind chill fac¬
tor) to attend the meeting held in
Minneapolis.
In addition to the presentations and
discussions, region members celebrated
the 40th birthday of Russ Murphy,
RRC, who was surprised with cake and
candles for all to share. Following is a
synopsis of the day’s events.
Gary Knault, Architectural
Consultants, Inc.
“Cold Weather Applications of
EPDM Roofing Systems”
Gary began his presentation by
explaining how and why cold weather
applications have become prevalent
during this decade, stating that roofing
and general construction became a yearround
activity in the ‘60s and ‘70s
because of the expense of time and
money. The ‘70s witnessed the prolifer¬
ation of EPDM and single-ply mem¬
brane systems into the market place.
Gary said that successful EPDM roof
systems have been installed at tempera¬
tures 36 degrees F below zero. While
pre-job planning and application prepa¬
ration are always important, they are
even more so in cold weather condi¬
tions. Equipment, storage needs, set-up
areas, common sense issues, and tools
need to be reviewed and checked prior
to the installation of the roof system.
Hot air guns, hot boxes, and pail heaters
must be fully operational. Dew point
concerns are also important. Safety —
always a concern — is critical at this
time of the year. Gary indicated that the
following items should be reviewed
with crew forces during cold weather
projects:
• Exposure concerns to workers.
• Roof decks which are slippery due
to snow, water and ice.
• Special considerations such as
snow or holes on roof decks.
• Precautions to take with progres¬
sive changes during the project
(e.g., diminishing daylight).
EPDM performance can be directly
related to the following concerns and
activities which consequently deserve
close attention.
• Membrane will not readily relax as
quickly in cold weather. Additional
time should be provided.
• Wet conditions must be avoided at
all costs.
• Cleaning with denatured alcohol
for lap seam preparation is
required.
• Solvent evaporation can leave a
layer of moisture and must be
appropriately dealt with.
Some obvious though often neglect¬
ed concerns in the application of EPDM
were reviewed:
• Do not leave adhesives outside;
they must be maintained at 60-80
degrees and should be stored in hot
boxes located on the site.
Adhesives on the roof should be
rotated every four hours.
• Do not use heat guns directly on
adhesives to flash off same. Heat
guns can be used on the reverse
side of the membrane.
• Do not use open flames on the
roof.
• The push/pull tack test is applica¬
ble in cold weather.
• VOC free materials do not work at
temperatures below 20 degrees .
The following are important
reminders for cold weather installations:
• The most important reminder is to
keep all surfaces dry before, dur¬
ing, and after the application of the
adhesive or cement.
• Solvents evaporating from the
cements and adhesives may cause a
thin moisture layer to form,
depending on the humidity level in
the air and the temperature.
• The dew point range must be con¬
sidered in the morning hours to
achieve dry surfaces as well as late
in the afternoon when the dew may
start forming.
• Accessories should be stored at a
60-80 degree temperature range.
• Do not take any more cements or
adhesives on the roof then you
intend to use within a four-hour
period.
• If cements or adhesives are left out
overnight, they must be stored at
60-80 degrees for three to five days
before reuse.
• Temperatures below 40 degrees
will cause the butyl/EPDM adhe¬
sives on pressure sensitive flashing
comers, pipes, and boots to lose
tack. Use a heat gun (not open
flame) to heat the EPDM flashing
side of the product (not the adhe¬
sive side).
• Only a heat gun (hot air) should be
used to warm pressure sensitive
and uncured flashing to a workable
state. Either product should be
April 1996 17
REGIONAL NEWS
heated above a warm tool tempera¬
ture of 105 degrees. Do not use
open flame to keep cements, adhe¬
sives, or other projects in a work¬
able condition on the roof.
• All pressure sensitive products lose
tack when exposed to temperatures
below 40 degrees. When this situa¬
tion is encountered, splice tape
must be moved to a warm area and
returned to a minimum of 60
degrees. All other pressure sensi¬
tive products can be heated with
the heat gun.
Russ Murphy, RRC,
Professional Services
Industries
“Project Profile: Cold Building
Envelope Investigation”
Continuing a regional tradition of
presenting unusual but interesting pro¬
ject histories, Russ Murphy led 50
attendees through a cold building enve¬
lope investigation. He explained the
current condition that warranted the
investigation, indicating that this rela¬
tively new building was experiencing
ice formation on the steel grids, stain¬
ing, and mold on the interior surfaces.
Since the investigation was ongoing, the
name of the manufacturer and certain
information could not be given —
adding an aura of mystery to the pro¬
ject. However, Russ was able to pass
onto the attendees some basic conclu¬
sions:
• The importance of thorough and
thoughtful design of the roof sys¬
tem and the integration of all the
systems of the building compo¬
nents,
• How important it is that construc¬
tion managers and general contrac¬
tors know the specific reasons for
the required construction. A pre¬
roofing meeting is a must.
• The ways in which building com¬
ponents can impinge upon the
integrity of a roof system must be
understood, not only by the archi¬
tects and roof consultants but also
by the construction engineers.
Russ Murphy’s presentation under¬
scored the amount of litigation that is
currently involving roofing and related
practices throughout the U.S. He
promises to follow up in the near future
with his conclusions and solutions.
Marc Allaire,
Industrial Roof
Consultants Group
“Design Considerations for
Cold Climate Environments”
Marc began his presentation by dis¬
tributing an excellent technical paper
entitled “Design Considerations for
Cold Climate Environments”. Marc’s
paper and presentation revolved around
a number of issues important to the suc¬
cessful design and installation of roof
systems in cold climates. The following
are areas of concern that Marc has
found to be critical to the development
of a quality roof system:
• Structural requirements. The
weight of snow is very important
and critical to the design of the
appropriate structural roof system
— not only the dry weight but the
condensed water- saturated weight
as the snow takes on water mois¬
ture. The anticipated amount of
insulation is also a factor.
• Vapor retarder requirements. Marc
recommends: when in doubt, use
them to prevent moisture flow and
migration and to reduce air leak¬
age, especially with ballasted and
mechanically fastened systems.
Marc reviewed the importance of
the interior relative humidity and
its effect on the dew point. He also
reviewed numerous materials that
could be used for vapor barriers
including kraft paper, polyethylene,
and two-ply asphaltic membranes.
He then showed with documenta¬
tion that, in trying to achieve vapor
barrier diffusion, some compromis¬
es (e.g., mechanically-fastened roof
systems) are acceptable. Indicating
that the amount of moisture trans¬
mission through small punctures is
minor, he said that all thermal
requirements regarding the installa¬
tion should meet the code and the
building owner’s requirements.
• Drainage. Positive slope to interior
drains is recommended. This will
keep not only the drain bowl and
pipe warm, but the resultant heat
loss through the drain bowl will
keep the drain free of ice and snow
during winter. Perimeter drainage
is very conducive to the production
of ice problems such as icicles and
ice damming.
• System selection. All factors
should be considered in the selec¬
tion of a roof system. The method
of attachment should be reviewed
and all manufacturers should be
thoroughly investigated.
• Installation. Follow and refer to
industry guidelines and enforce
manufacturers recommendations;
utilize a level of common sense.
Also take into consideration wind
chill, a factor often not given cre¬
dence in the installation of roof
systems.
• Material storage. Asphalt “pigs”
should be kept dry and covered, as
should all roll goods. Tarps should
be of a vapor transmissive nature
like canvas. Protection of flashing
materials is also recommended.
Marc offered specific recommenda¬
tions which include:
• Allow for snow removal.
• Be specific on storage require¬
ments, (i.e., hot boxes and material
temperature requirements).
• Be specific on night cutoffs, as it
could be months before the contin¬
uation of roofing operations take
place.
• Be specific on substrate acceptabil¬
ity. For example, does frost have to
be removed, how should it be
removed, and when is “dry” dry?
• Be specific on the minimum or
maximum working temperature
conditions.
Since designing roof systems in cold
weather is different from the norm, the
designer must be aware of the forces
acting on the building envelope.
Recognizing and understanding the
18 Interface
regional news
effects of snow, ice, cold winds, high
interior humidity, and cold temperature
will help avert the dangers commonly
associated with northern designs.
Practical considerations of the installa¬
tion of the system must be included
along with the design. The assembly as
a whole must resist all the forces
imposed on it.
Ken Flinkenger,
Sarnafil
“Cold Weather Applications
of PVC Roof Systems”
Ken reported that successful installa¬
tion of PVC membranes has been
accomplished in temperatures as low as
45 degrees below zero at the U.S.
Navy’s research center in Antarctica.
While Ken does not recommend the
installation of roof systems under those
conditions, he did underscore the point
that, with proper preparation and instal¬
lation, quality roof systems are achiev¬
able in cold weather. As a law of cold
weather roofing, there are a number of
critical areas regarding PVC installation
that should be respected:
• The lower the temperature, the
lower the Leister machine hot air
weld temperature should be. High
welding temperatures will scorch
the membrane.
• Prior to installing lap seams, all
moisture must be removed from
same. Do test welds to properly
gauge the machine.
Ken reviewed the critical areas and
concerns needed for the success of a
PVC roof system including:
• Start-ups.
• The review of stops and starts.
• The proper location of insulation
joints.
• A change in planes (where tapered
insulation ends at roof drains, base
drains, peaks and valleys); all must
be reviewed along with proper tieins.
Personnel should be experienced in
the installation of roof systems in cold
weather and be properly clothed. Ken
The next Region
Three meeting will
be held in St.
Louis, Missouri, in
late July. Ideas for
topics and/or a
summer outing
are invited. Call
Director Tom
Hutchinson at
(312) 258-9595.
gives the following recommendations
for materials and installation:
• Canvas tarp should be used to pro¬
tect all goods from snow and the
elements.
• All materials should be elevated
above the roof deck level.
• Protect the installed roof areas from
foot and/or material traffic.
Following is a cold weather check¬
list:
• Appropriate equipment, checked
and in order.
• A power source, 7,500 Watt mini¬
mum with a test voltage tag.
• Extension cords, maximum 100
feet long.
• Extra heating elements for main¬
taining the heat guns.
• Pressure distributing wheels on the
Leister machine should be in con¬
tact with the membrane at all times.
All functioning parts of the Leister
machine must be properly main¬
tained.
• All lap seams should be probed
with a round-edge screw driver.
Vance Burnett,
Capital Development
Board
“Roofing and the Roof
Consultant from the Perspective
of a Government Body”
Vance Burnett is the project adminis¬
trator for the Capital Development
Board in the State of Illinois, represent¬
ing the largest single property owner in
the state (and Illinois is among the top
ten states). Vance indicated that,
through his direct involvement with the
oversight of 58,000 buildings within
Illinois, he has seen the good and bad in
roofing. His explanation is that archi¬
tects and engineers have very little edu¬
cation in the application and design of
roof systems. Vance reviewed the gov¬
ernment’s current selection process for
roof consultants and architects and stat¬
ed that over 50 percent of the litigation
is related to roofing (comprising five
percent of all buildings). In summary,
poorly developed contract documents as
well as marginal installations are cost¬
ing the taxpayers of Illinois millions of
dollars each year — money that could
be saved with proper installation.
Ardeth Rudolph,
Gammie Nuclear
“Moisture Surveys”
Ardeth reviewed the potential uses of
moisture surveys including the location
of moisture within a roof system and
the potential location of moisture entry.
He said that building owners are lately
requesting moisture surveys following
the completion of a new roof system.
They hope to establish a condition to
which future surveys can be compared
and to determine whether the new roof
system was compromised either during
its installation or afterward by other
tradesmen.
The potential for and the execution
of nuclear surveys were reviewed along
with their advantages and disadvan¬
tages. One advantage of nuclear surveys
is that they can be performed with
water on the roof or during inclement
time periods. Mr. Mike Hornung,
Director of Facilities for a Chicago sub¬
April 1996 19
REGIONAL N E W S
urban school district, came forward to
review his experiences from the perspective
of a building owner. Mike then moderated a
spontaneous, lively discussion on the numer¬
ous aspects of moisture surveys. Such dis¬
cussions and debates will be encouraged at
future meetings.
Set your calendars for late July when the
summer meeting will be held in St. Louis.
Ideas for potential topics and a summer out¬
ing are encouraged.
Why Join RCI?
RCI is more than just another industry association.
It is a fellowship of professionals who learn from
each other and who share a common goal of sus¬
taining the highest standards. Following are some
of the benefits of membership.
■ Client referrals.
■ International membership directory pub¬
lished annually.
■ Annual convention and trade show.
■ Education and training courses and pub¬
lications.
■ Information library and database of ref¬
erence material.
■ Internationally-recognized registration titles.
■ Regional seminars and meetings.
■ Interface journal of technical papers and
industry practices.
■ Standards of ethical practice.
■ Networking and a supportive fellowship.
■ Increased involvement and visibility
within the industry.
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