Re-Roofing
EXPERT EPDM RUBBER RE-ROOFING:
- 45 mil Reinforced EPDM Rubber, mechanically fastened
installation, including 1/2" buffer board - $2.00/sf
- 45 mil plain black EPDM Rubber, fully adhered
installation with adhesive, including 1/2" buffer board - $2.25/sf
- 60 mil Reinforced EPDM Rubber, mechanically fastened
installation, including 1/2" buffer board - $2.30/sf
- 60 mil plain black EPDM Rubber, fully adhered
installation with adhesive, including 1/2" buffer board - $2.50/sf
- Existing gravel surface roofs may involve additional
charges for gravel removal necessary to complete installation ($0.50/sf for
typical gravel roof with normal access)
- Complete tear-off of existing roof to decking and
installation of new insulation prior to EPDM installation - Call for Prices!
Prices valid for existing commercial repair and re-roofing projects in the
Twin Cities Metro area, 3000 square feet minimum, with normal access. Ballasted
roofs and roofs with significant drainage problems (low spots, pools of standing
water), and some heavily graveled built-up roofs may involve additional charges.
Background
Because of the increasingly sophisticated oil refining processes that remove more and more of the light,
volatile oils that give asphalt (a by-product of oil refining) its longevity, the quality of asphalt had been
steadily deteriorating for several decades. In 2009, the use of conventional built-up tar-and-gravel roofs is
considered an anomaly, rather than an industry standard.
Conversely, the consistent high quality, longevity, and uninterrupted service life of a number of
technologically advanced roofing systems has made those systems substantially more preferable than asphalt
built-up for both new construction and re-roofing applications.
With impressive, proven track records of 25 to 40 years of service life, the "new technology" roofing
systems have easily replaced asphalt built-up as the installation of choice for
commercial applications. The most popular system (as well as the most economical
on a cost-per-year basis) is EPDM Rubber. EPDM Rubber has become the new standard
for both new and retrofit commercial roofing applications.
EPDM ("Rubber")
The EPDM Roofing Association states simply that: "The EPDM (ethylene propylene diene terpolymer) single-ply
rubber roofing membrane has been an appealing choice of the low-slope commercial roofing industry for over 40
years."
Even more impressive is the fact that (again quoting the EPDM Roofing Association): "The number one
roofing choice of architects, roof consultants and contractors for both new construction and replacement
roofing projects according to market surveys from Building Design and Construction, and
Roofing/Siding/Insulation magazines, and the National Roofing Contractors Association (NRCA)".
Typical low-end installations of uncured, unreinforced 45 mil (thickness) EPDM often last longer than
their 10-year life expectancy. Higher grade installations that use the much better quality 45 mil reinforced
or 60 mil reinforced EPDM membrane have a conservative life expectancy greater than 25 years.
The most popular installation methods for EPDM Rubber are mechanically-fastened
(in which the seams and endlaps of 7' or 10' wide
sheets are securely fastened with barbed metal plates and screws at 12" intervals) and fully-adhered (in which wider
sheets, typically 10' or 20', are broomed into a solid layer of special adhesive).
A third method, loose-laid ballasted, is popular with contractors, but much less so with building owners
because of the difficulty and expense of locating and repairing the inevitable leaks. In ballasted
applications, the seams and endlaps of the membrane are fused together with adhesive, and the entire assembly
is held in place with a covering of rock. Because installations can be made by relatively unskilled and
less-experienced personnel, ballasted installations often suffer from a lack of quality that makes them the
least desirable alternative of the installation methods.
Re-Roofing
In the case of retrofit roof installations, the existing roof surface is a
major factor in the choice of materials. For smooth-surface roofs, EPDM Rubber
can be applied directly over the existing roof, or over a buffer provided by a
layer of rigid fiberboard insulation, and provide many years of uninterrupted,
problem-free service.
On gravel-surface roofs, installation of a buffer of rigid fiberboard
insulation is required to prevent damage to the EPDM Rubber roof membrane. When
loose gravel is left on the roof, two layers of rigid fiberboard insulation,
installed with staggered joints, is the preferred method of installation. The
extra layer assures that the loose gravel will not work up between the joints of
the insulation boards. When longevity and uninterrupted service life is the
primary decision factor, EPDM Rubber is the uncontested first choice in commercial
roofing.
We install premium-grade EPDM Rubber roofs at prices that are typically
20-40% below the "going rate" charged by contractors in the Twin Cities. Hiring
us to re-roof your commercial building with EPDM is not just cost-effective; it
is good business.
Typical EPDM Re-Roofing Specification
When comparing prices, contractors, and installers, it is best to make valid comparisons. The lowest
price (and in some cases, the highest price) may not be the best deal. Every work proposal should include
explicit details regarding the scope of work and the installation techniques that will be used.
We propose to furnish all labor, material, and equipment necessary to install high density fiberboard
insulation and EPDM roof membrane on the existing built-up tar and gravel at 123 Main Street, Minneapolis, MN
as follows:
- Sweep up existing loose gravel, dirt, and debris and remove from premises.
- Locate and fill existing low spots with one or more layers of 1/2" high density fiberboard sheathing to
facilitate drainage.
- Install a continuous layer of 1/2" high density fiberboard sheathing to cover entire roof area. Sheathing
is to be secured with 12 or more fasteners per 4’ x 8’ exposed sheet, consisting of 3” galvalume plates and
self-tapping screws of sufficient length to penetrate decking at least 1".
- Install 6" Reinforced EPDM termination strip, butyl adhesive side up, adjacent to and parallel to walls,
curbs, skylights, and any roof projection that requires flashing. Secure termination strip with 3" diameter
galvalume plates and self-tapping screws of sufficient length to penetrate decking at least 1".
- Install 45 mil Reinforced EPDM roof membrane using mechanically-fastened installation method with 2”
barbed metal plates and self-tapping screws of sufficient length to penetrate decking at least 1", placed
approximately 12” on center along upper edge of each sheet.
- Clean, prime, and seal all seams and endlaps of EPDM using In-Seam Tape and hand-roll each seam across and
along the seam after joining to assure proper adhesion.
- Install 6” wide strip of Cover Tape or a 6” or wider strip of EPDM set in
EPDM Contact Adhesive on
all endlaps. Hand-roll each endlap covering across and along
the covering after joining to assure proper adhesion.
- EPDM membrane is to be turned up existing walls, curbs, skylights, and any roof projection that requires
flashing, a minimum of 12" or a sufficient distance to extend up underneath existing counterflashing at least
2".
- Peel backing strip from butyl adhesive strip on previously installed 6" Reinforced EPDM termination strips,
and hand-roll EPDM membrane along and across the butyl adhesive strip to assure proper adhesion.
- Roll EPDM membrane back a distance equal to height of flashing, and apply a layer of EPDM Contact Adhesive
to back of EPDM membrane and to area of flashing on wall, curb, skylight, or other roof projection.
- When adhesive becomes tacky to the touch (20-30 minutes), roll the EPDM membrane into contact with the
flashing surface, starting with the center of sheet, and working toward the ends. Hand-roll the entire area of
flashing to assure complete adhesion of the EPDM membrane to the flashing area.
- Apply a bead of Water-Stop EPDM caulking along the top of all newly-installed EPDM flashings,
approximately 1" below the lower edge of existing counterflashing.
- Install All-Purpose Termination Bars at the top of all newly-installed EPDM flashings, centered on the
bead of Water-Stop caulking, and secured with appropriate fasteners on 12" centers.
- Install new EPDM pipe collars and pre-formed EPDM collars on all roof projections that do not
have counterflashing.
- Re-seal all pipes, vents, and roof projections with Water-Stop EPDM caulking.
- Remove job debris from premises.
- Work is to begin on (insert date), and to be substantially completed by (insert date), weather conditions
permitting.
Unless your contractor or installer is willing to specify the exact detail of installation method, you
should be highly skeptical about what the finished product may turn out to be. Specifically, unless at least
the major steps specified above are included in the work order, the contractor or installer may not be
experienced enough with EPDM installations to install a decent roof on your building.
Experience installing other types of roofs, particularly asphalt built-up (tar and gravel) or shingle,
is no guarantee of competence in installing EPDM roof membranes. EPDM requires specialized tools and
installation techniques that are absolutely essential to take advantage of the long and trouble-free life
available with EPDM roofing.