4) Increase Roof Life
goal is more complex than it sounds, as there are so many variables
involved. Each major roof type will have some unique features that
Bituminous roofing systems: Multiple
layers and field assembly mean that blisters between layers can occur.
Avoid traffic over blisters and promptly repair broken blisters. Neither
asphalt nor coal tar pitch weathers well if its opaque surfacing has
eroded away. Simple repairs can be done with asphalt mastic and fabric
such as woven glass fiber mesh or non-woven polyester.
Polymer-modified bituminous systems: SBS
is generally installed as a base sheet and mineral-surfaced cap sheet
combo. These sheets can be installed and patched with hot asphalt. APP
has a higher melt point, so torch application is used instead of mopping
because it permits localized patching. Both APP and SBS systems require
trained applicators and tools.
Elastomeric roofing systems: Large prefabricated panels of EPDM have extraordinary
weather resistance but rely upon relatively narrow seams for
water-tightness. Surface cleaning, priming, and application of target
pieces of new membrane or flashing are needed. Many repair materials
have a short shelf life, so the roofing contractor that installed and/or
one that is approved by the roof warrantor may be needed.
Thermoplastic roofing systems:
These sheets are generally light-colored and internally reinforced with
scrim or fabric. Subcategories include PVC, TPO, KEE, and CSPE. Repairs
depend upon weldability,
which, in turn, may require surface preparation and hot-air fusion.
Expect erosion down to the scrim. Special techniques for resurfacing
depend upon the chemical make-up of the original membrane.
All roofing systems: All
roofing systems should be visually inspected for deficiencies and
failures, but some components are hidden from view. Depending upon the
design of the system (when a vapor retarder is in place, for example),
design may actually hide damage from water intrusion. Click here for a sample visual inspection sheet.
or when water intrusion is expected, consider bringing in an expert to
look for water in roof insulation using infrared scanning, capacitance,
or neutron backscattering techniques and recommend how to deal with
moisture before utility expenses soar and structural and interior damage
result. Quest Construction Products details how to recognize damage
patterns and perform field tests in a presentation from the
International Roof Coatings Conference here.
A note on spray foam insulation: Sprayed
polyurethane foam consists of expanded two-component polyurethane foam
followed by an opaque coating of liquid urethane, acrylic, or silicone
elastomer. It generally requires recoating before the surfacing erodes
away because the underlying foam is not UV-resistant. Typical recoating
will be required within 7-10 years. Field repairs are generally needed
for punctures using a compatible caulk to fill in voids.
5) Improve Safety
a single employee as the in-house roof overseer with reliance upon
qualified outside experts as required. Roofing conventions and webinars
are available, as well as training programs conducted by material
manufacturers. These training programs should focus expressly on the
roof systems in place on your building complex. Extend the training to
any other personnel who need to access a roof surface and make sure the
MSDS is available and understood.
Richard (Dick) L. Fricklas was technical director emeritus of the Roofing Industry Educational Institute prior to his retirement. He is co-author of The Manual of Low Slope Roofing Systems
and continues to participate in seminars for the University of
Wisconsin and RCI Inc., the Institute of Roofing, Waterproofing, and
Building Envelope Professionals. His honors include the William C.
Cullen Award and Walter C. Voss Award from ASTM, the J. A. Piper Award
from NRCA, the William C. Correll award from RCI, and the James Q.
McCawley Award from the MRCA. Dick holds honorary memberships in both
ASTM and RCI Inc.
Using Check Sheets for Rooftop Inspection
Create an inspection program with roofing check sheets.
Roofing: The Benefits of Record-Keeping
When something goes wrong with your roof, accurate roofing files can lead you to the answer.
Safety with Roof Systems
Tips on spotting roof hazards.