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EPDM Section 3: Separator Sheets and Auxiliary Leveling Surfaces

EPDM-3.1 Separator Sheets

EPDM-3.1.1 General

.1

Separator sheets are materials used to separate roofing system components, to prevent material incompatibility or to prevent adhesion.

.2

Separator sheets are not required for uninsulated fully adhered E.P.D.M. membrane systems.

.3

Separator sheets are not accepted for uninsulated ballasted or mechanically fastened E.P.D.M. membrane systems, refer to auxiliary leveling surface requirements.

.4

For conventional insulated E.P.D.M. design, the vapour retarder membrane will serve as the separator sheet.

.5

All bitumen based materials must be removed or covered with an acceptable separator sheet as E.P.D.M. membrane is not compatible with bitumen products.

EPDM-3.2 Auxiliary Leveling Surfaces

EPDM-3.2.1 General

.1

An auxiliary leveling surface is a material used to provide a smooth substrate to which roofing system components can be adhered.

.2

For loose-laid and ballasted designs the auxiliary leveling surface may be loose-laid.

.3

When mechanically fastening auxiliary leveling surfaces, fastener type, size and spacing shall be in accordance with the membrane manufacturer’s requirement for the deck and system type used.

EPDM-3.2.2 Fully Adhered Systems

EPDM-3.2.2.1 Dimensional Lumber Decks

.1

A single layer of minimum 12.7mm (½ ”) thick exterior grade plywood or 11.1mm (7/16") thick O.S.B. sheathing, mechanically fastened with wood screws, shall completely cover lumber decks.

.2

O.S.B. sheathing shall be installed with its smooth side up.

EPDM-3.2.2.2 Plywood and O.S.B Decks

.1

An auxiliary leveling surface is not required.

EPDM-3.2.2.3 Concrete Decks

.1

Auxiliary leveling surfaces are not required for cast-in-place or precast concrete roof decks.

EPDM-3.2.2.4 Steel Decks

.1

ARCA accepted auxiliary leveling surfaces may be comprised of a minimum 9.5mm (3/8") thick Fibre Reinforced Gypsum Panel (ASTM 1278), 12.7mm (1/2") thick Glass Mat Gypsum Substrate (ASTM 1177), 12.7mm (1/2") thick Glass Mat Gypsum Substrate (ASTM C1396), 12.7mm (1/2") thick plywood, or 12.7mm (1/2") thick O.S.B. when not used as a thermal barrier.
Revised

2017-04

.2

To qualify for an ARCA 15 Year Warranty Certificate, a minimum 12.7mm (1/2”) glass faced gypsum auxiliary leveling surface shall be mechanically fastened to the structural deck.
Added

2016-08

EPDM-3.2.2.5 Bituminous and Cementitious Deck Fills

.1

Deck fills are not permitted with fully adhered E.P.D.M. membrane systems.

EPDM-3.2.3 Loose-Laid Ballasted and Mechanically Fastened Systems

EPDM-3.2.3.1 Dimensional Lumber Decks

.1

In an uninsulated system, a single layer of minimum 12.7mm (½”) thick fiberboard or perlite roof insulation shall completely cover dimensional lumber decks.
Revised

2016-06

EPDM-3.2.3.2 Plywood and O.S.B Decks

.1

In an uninsulated system, a single layer of minimum 12.7mm (½”) thick fiberboard or perlite insulation shall completely cover plywood and O.S.B. decks.

EPDM-3.2.3.3 Concrete Decks

.1

In an uninsulated system, a single layer of minimum 12.7mm (1⁄2”) thick fiberboard or perlite roof insulation shall completely cover precast and cast-in-place concrete decks.
Revised

2016-06

EPDM-3.2.3.4 Steel Decks

.1

In an uninsulated system, a single layer of minimum 25mm (1”) thick fiberboard or perlite insulation shall completely cover steel decks.
Revised

2016-06

EPDM-3.2.3.5 Deck Fills

.1

In an uninsulated system, a single layer of minimum 12.7mm (½”) fiberboard or perlite roof insulation shall completely cover bituminous deck fills.
Revised

2016-06

.2

Cementitious deck fills are not permitted for Warranty Certificate issuance.