Moisture Control | Roof
Decks | Rigid Insulation
| Roof Membranes
& Project Walk Through
The owner, designer, general contractor, roofing contractor, inspector,
deck contractor, mechanical contractor, and any other interfacing parties
involved with the roofing project shall be requested to attend a preinstallation
conference. The conference shall be scheduled well in advance of delivering
the roof system components and the start of the roofing project. If
a guarantee is requested, a representative from Fields is required to
be present. A written record shall be made of the preinstallation conference
by the designer, and shall become a part of the job record. The deck
shall be inspected, and if any deficiencies with the deck are observed,
a second deck inspection shall be done to verify that corrective action
has been completed, and that written approval to proceed has been obtained
from the designer and from Fields for guaranteed system.
The roofing assembly plans, specifications, building codes, and contract
documents shall be reviewed during the preinstallation conference. Any
discrepancies between the foregoing and Fields requirements shall
be resolved for guaranteed systems.
The Following are Required during the Preinstallation Conference:
1. Coordination of interfacing trade schedules, with project sequencing,
including timely installation of any required equipment on the roof
so as to avoid or limit traffic over the roof system membrane.
2. Establishment of construction trade schedules and practices including
installation of a temporary roof and walkways so as to prevent damage
to the roof system membrane.
3. Construction of walls, curbs, drains, and other deck penetrations
prior to start of installation of the roof system.
4. Designation of access, staging, and storage areas on the project
5. The definition of acceptable weather conditions and working temperatures.
For guaranteed systems, Fields must agree in writing to less stringent
weather conditions than those stipulated in the Waterproof Membrane
Construction section at the bottom of page 62.
6. Provision for on-site monitoring after the roof system has been installed
so as to ensure that other trades do not damage the roof system.
7. Clarification of related EPA and OSHA regulations, including the
safety of all personnel on the project site.
If any changes in the project specifications or conditions are desired,
the party requesting the change shall:
1. Send written notice requesting the desired changes to all interfacing
2. Obtain written agreement of the desired changes from the designer,
and for guaranteed systems from Fields.
Wood Nailer & Back-Nailing Requirements
Each layer of reinforcing sheet shall be back-nailed on roofs with slopes
of 2 or more per horizontal foot. Reinforcing sheets fastened
to concrete decks, shall be fastened to preservative treated wood nailers
embedded into the concrete. The wood nailer dimensions shall be a minimum
of 1 x 4. Nailers shall be installed perpendicular to the
roof slope, and on 16 centers or less for slopes greater than
2 per horizontal foot, and on 4 centers or less for slopes
greater than 3 per horizontal foot.
General Waterproof Membrane Construction Criteria
1. Roofing components shall only be installed during dry, frost-free
conditions with precipitation forecast at less than a 10% chance for
rain, and with temperatures above 50æF.
2. Slope shall be provided for positive drainage of the roof assembly.
The criteria for determining positive drainage is that there shall be
no standing water on the roof assembly 48 hours after a rain following
dry weather conditions. A positive drainage design also includes the
correct number, size, and placement of roof drains, scuppers, and gutters
as well as crickets and saddles with sufficiently sloped valleys.
3. Entrapment of moisture shall be prevented during installation of
the roof system components. Moisture in or on components can cause the
roof system membrane to blister. If precipitation occurs prior to the
completion of the roof system membrane, the installation area shall
be dried or allowed to dry before continuing the project.
4. On roofs where the slope is greater than 2 per horizontal foot,
the roof system reinforcing sheets shall be installed parallel to the
slope. This method of installation is termed as strapping
the sheets and may be employed on lower slopes as well.
5. Roof system reinforcing sheets shall be installed continuously. Irregularities,
such as ridges, blisters, or raised seams shall be cut and repaired
prior to installation of additional reinforcing sheets, surface coatings,
or the application of reflective surfacings.
6. If conditions do not permit installation of the complete roof system
membrane, and the area must be exposed overnight, it is required that
the ply sheet laps be sealed either with the specified Fields Asphalt
coating or M300 RubrMastic prior to departing the project site for the
day. All installed reinforcing sheets shall at a minimum be glaze coated
with asphalt to temporarily seal the surface at the end of each days
installation. A wide blade squeegee shall be used to uniformly apply
the glaze coating so as to help achieve a thin film of 2 gallons of
ambient applied asphalt or 15 pounds of hot applied asphalt per 100
7. Roof traffic shall be prohibited over recently installed reinforcing
sheets so as to prevent the displacement of soft asphalt which is termed
a void, until the asphalt has set-up firm enough for light traffic.
8. The substrate shall be dry, frost free, clean, smooth, and firm.
Only the products specified are permitted on the project site. All products,
including coatings and mastics, are required to be asbestos free. Each
layer of reinforcing sheets, or pre-manufactured membranes shall be
started at the same location and installed parallel to all other layers.
The flow of water shall be over or parallel to seams, but never against
seams. All reinforcing sheets shall be adhered into the specified Fields
Asphalt. Each base and ply sheet shall be broomed into the asphalt to
ensure a fully adhered, smooth installation. Base sheet side laps shall
be a minimum of 2. The quantity of shingled ply sheet layers is
the basis for calculating the ply sheet side laps. In no place shall
any sheet touch sheet. Reinforcing sheets and pre-manufactured membranes
shall extend a minimum of 2 above the top of cants. End laps shall
be a minimum of 6 and offset at least 36. The specified
Fields Asphalt adhesive, shall be uniformly applied at the following
rates per 100 square feet: Ambient applied asphalts 4 gallons, and hot
applied asphalts 30 pounds.
9. The 4 types of membrane reinforcing sheets are: base sheets, ply
sheets, BasePly sheets, and cap sheets.