Template:All Systems - MEMBRANES SBS

1 General

While the roof is being applied, all membrane openings at eaves, walls, vents, etc. must be sealed to prevent moisture from entering roofing or between plies of stripping.

Membrane Surfacing and Slope Limitations (Modified Bitumen Membranes): Only factory cap sheets are to be used on slopes exceeding 1:24 (1/2" in 12"). Manufacturers published instructions as to application methods, materials, and slope limitations are to be followed. On slopes less than 1:24 (1/2" in 12"), double pour, modified double pour or alternate modified double pour and gravel surfacing may be used (see Guarantee Standards reference needed).

NOTE: Fully nailed base sheet and torched cap sheet is considered a single-ply for Guarantee purposes.

Both the base sheet and cap sheet in 2-Ply modified bituminous systems must be of modified bitumen materials using the same polymer. For example, if the cap sheet is an SBS modified bitumen sheet, then the base sheet must be an SBS modified bitumen sheet. Oxidized asphalt sheets will be considered as underlay only and must not be counted as one of two plies.

Both the base sheet and cap sheet must be installed in a parallel direction (not at 90° to each other). Manufacturer's printed instructions for overlaps are to be followed.

For the application of 2-ply ungranulated membranes; both the cap sheet and base sheet are to be applied separately. Shingle fashion application (i.e., 50% lap) is not acceptable except where membrane back nailing is required.

All modified bitumen base stripping terminating on vertical surfaces must be mechanically fastened.

Membrane Lap Preparation for Modified Bitumen Roof Systems:

• Granules are to be embedded prior to forming laps on all torch applied modified bituminous cap sheets.
• Membrane end lap corners must be cut on a bias (clipped or trimmed on an angle) prior to forming laps on all torch applied modified bituminous membrane roof systems.

Application to Wood Decks

Direct torch (open flame) to wood surfaces is NOT permitted. All wood surfaces, decks, walls, blocking, cants, etc., MUST be protected from torch (open flame) by an acceptable separation or overlay material. Acceptable options include:

.1 RGC accepted self-adhered and cold adhesive applied membranes installed over wood surfaces to manufacturers’ product installation specifications. Self-adhered membranes must not be installed on contaminated wood surfaces. A minimum 9.5 mm (3/8") nominal thick plywood sheeting (overlay) must be installed over all contaminated wood surface (eg. asphalt) to receive self-adhered membranes. Metal wall base flashing is optional with these application methods.

A reverse lap application method for base sheet and base sheet flashing (stripping), at roof up stand transitions, is permitted when self-adhered base sheet flashing is used as flame protection for wood surfaces. Use of the reverse lap method must be an acceptable application method to the membrane manufacturer. The self-adhered base sheet must extend a minimum of 150 mm (6") onto the roof surface. The heat welded field membrane must be turned up at the vertical surface a minimum of 100 mm (4") or a heat welded base sheet transition gusset extending 100 mm (4") onto the roof and upstand surfaces be installed.

.2 Mechanically Attached Base Sheet – Cover wood surfaces with a minimum No. 40 asphalt coated fibreglass base sheet conforming to CAN / CSA – A123.16 – M88 (R1996), Type II or manufacturers’ accepted base sheets of equal or greater weight and reinforcement. Attachment of base sheets shall be a minimum of one nail, with a minimum 25mm (1") nominal head size, per 0.093 m2 (1 sq. ft.), or one plate and screw per 0.186 m2 (2 sq. ft). Lap base sheet end laps minimum 150 mm (6"), mechanically fix laps at 100 mm (4") o/c and seal all corner details with membrane manufacturers’ approved self-adhered SBS membrane or tape. Wood surfaces must be “dry mop” dry, no pooling or standing water permitted. Metal base flashing is required on all vertical surfaces, walls, curbs, etc., that are 200 mm (8") or greater in height above the finished roof surface, when the mechanically attached base sheet method is used.

.3 Asphalt core overlay boards, [minimum thickness 4.5 mm (3/16") nominal] or insulation and insulation overlay boards specifically designed for torch applications, that are accepted by RGC, mechanically attached with nails with a minimum 25 mm (1") nominal head size placed a minimum of one nail per 0.093 m² (1 sq. ft.) or plates and screws placed a minimum of 0.186 m² (2 sq. ft.). Seal all board joints and wall transitions with membrane manufacturer’s approved self-adhered membrane or tapes. Alternatively a mechanically attached minimum No. 25 asphalt coated fibreglass base sheet conforming to CAN / CSA – A123.16 – M88 (R1996), Type II or No. 30 non-perforated felt conforming to CSA A123.3-M may be used prior to installing asphalt core overlay boards on wood decks. Metal wall base flashing is optional with these application methods. Wood surfaces must be “dry mop” dry, no pooling or standing water permitted.

.4 Hot Asphalt Adhered – Install modified bituminous stripping (flashing) membranes to manufacturers’ installation specifications with conventional Type 3 or 4 oxidized asphalt or Type 3 or 4 SEBS modified asphalt. Metal base flashing is required on all vertical surfaces, walls, curbs, etc. when hot asphalt is used to adhere stripping (flashing) membranes.

Cold Weather Membrane Applications:

In cold weather regions, membrane selection must conform to the membrane manufacturer’s recommendations for January in service design temperature.

2 Single-Ply Modified Bituminous Membranes

Membranes used for a single ply modified bituminous membrane system adhered or mechanically fastened shall be a minimum thickness of 3.5 mm on the selvage edge, with a minimum 150 g / meters squared polyester or equal strength polyester-fibreglass combination reinforcement.

Torch applied membrane applications require a deck separation sheet of a minimum No. 40 asphalt coated glass base sheet or torchable overlay board. Direct torch application to wood surfaces is not permitted.

A minimum slope 1:15 (3/4" in 12") is required. Any roof areas less than 1:15 (3/4" in 12") require 2 ply membrane assemblies.At roof slope transitions locations where slopes of less than 1:15 (3/4" in 12") meet steeper slopes a two ply membrane assembly must be carried 900 mm (36") beyond the lower sloped roof transition point.

Membrane gussets must be installed to all inside and outside corners.

Modified Bituminous Base Sheet pre-stripping ply required at all perimeters, upstands and penetrations. Direct torch application to wood surfaces is not permitted.

Cap sheet stripping is required and must extend 150 mm (6") horizontally and 200 mm (8") vertically from the base of all upstands.

All stripping terminating on vertical surfaces must be mechanically fastened.

3 Mechanically Attached

On all adhered flexible membrane roof slopes that exceed 1:24 (1/2" in 12"), the manufacturer's published instructions are to be followed regarding mechanical fastening and/or back nailing of sheets, and the size and direction of sheet application to the direction of roof slope.

All mechanically fastened flexible membrane systems installed under RoofStar guarantee shall conform to the CSA A123.21-10 Standard test method for the dynamic wind uplift resistance of mechanically attached membrane roofing systems and/or the Factory Mutual I-90 Listing for mechanically attached assemblies.

Mechanically Attached Base Sheet

Cover wood surfaces with a minimum No. 40 asphalt coated fibreglass base sheet conforming to CAN / CSA – A123.16 – M88 (R1996), Type II or manufacturers’ accepted base sheets of equal or greater weight and reinforcement. Attachment of base sheets shall be a minimum of one nail, with a minimum 25mm (1") nominal head size, per 0.093 m2 (1 sq. ft.), or one plate and screw per 0.186 m2 (2 sq. ft). Lap base sheet end laps minimum 150 mm (6"), mechanically fix laps at 100 mm (4") o/c and seal all corner details with membrane manufacturers’ approved self adhered SBS membrane or tape. Wood surfaces must be “dry mop” dry, no pooling or standing water permitted. Metal base flashing is required on all vertical surfaces, walls, curbs, etc., that are 200 mm (8") or greater in height above the finished roof surface, when the mechanically attached base sheet method is used.

4 Self-Adhered Membranes

Base and cap sheets of all self-adhered and cold adhesive applied roof systems must be installed in the same work day, phased installation of base and cap sheet membranes is not permitted.

RGC accepted self-adhered and cold adhesive applied membranes installed over wood surfaces to manufacturers’ product installation specifications. Self-adhered membranes must not be installed on contaminated wood surfaces. A minimum 9.5 mm (3/8") nominal thick plywood sheeting (overlay) must be installed over all contaminated wood surface (eg. asphalt) to receive self-adhered membranes. Metal wall base flashing is optional with these application methods.

Both the base sheet and cap sheet membrane must be competed in the same work day on all modified bituminous self-adhered systems. Specifications and manufacturers written application instructions must be strictly followed. Phased installation of membranes is not permitted.

Self-adhesive membranes must only be installed when ambient temperature meets or exceeds the manufacturer’s printed product installation temperatures. All self-adhesive field membranes must be fully rolled with a manufacturer’s accepted roller that is a minimum 34.2 kg (75 lbs.) or greater and provides an evenly dispersed weight. All flashing (stripping) membrane must be hand rolled with a membrane manufacturer’s accepted roller.

5 Cold-applied (Adhered) Membranes

As stated earlier, Base and cap sheets of all self-adhered and cold adhesive applied roof systems must be installed in the same work day, phased installation of base and cap sheet membranes is not permitted.

Both the base sheet and cap sheet membrane must be completed in the same work day on all adhesive applied modified bituminous systems. Specifications and manufacturers’ written application instructions must be strictly followed. Phased installation of membranes is not permitted.

RGC accepts self-adhered and cold adhesive applied membranes installed over wood surfaces to manufacturers’ product installation specifications. Self-adhered membranes must not be installed on contaminated wood surfaces. A minimum 9.5 mm (3/8") nominal thick plywood sheeting (overlay) must be installed over all contaminated wood surface (eg. asphalt) to receive self-adhered membranes.

6 Protected and Modified Protected Membranes

On all protected and modified protected membrane roofing projects, a filter mat of approved material is to be properly installed between gravel ballast and insulation. The filter mat is required under pre-cast pavers that are used as ballast or walkways.

Insulation, which is bonded or mopped directly to the roof membrane, is not acceptable.

Concrete Ballast, Poured-in-place concrete or concrete topping as ballast or traffic topping is not permitted in the roof guarantee programs (see section 2.1.5 Waterproofing Membrane Systems). Only ballast, which permits easy or reasonable access to the membrane, is acceptable.

Acceptable ballast includes: properly sized gravel, concrete pavers, concrete-topped insulation, etc.

Gravel Ballast: Protected Membrane and Ballasted Membrane (EPDM, TPO, PVC, etc.) Shall be clean, washed, round or crushed stone, falling within the following gradations:

35 mm (1-1/2") - 100 % Passing 25 mm (1") 70 - 100 % Passing 20 mm (3/4") 5 - 20 % Passing 12.5 mm (1/2") 0 - 6 % Passing 5 mm (3/16") 0 - 2 % Passing

Any variance to the above must be accepted by the owner or the owner's representative and be confirmed in writing.

Pedestals: Installation of proprietary (purpose-made) pedestals, with integral spacer ribs for uniform spacing of pavers, or an accepted drainage layer designed to provide vertical separation between pre-cast pavers and substrate or other underlying materials, is mandatory. The use of proprietary drainage boards or pea gravel with filter fabric to provide drainage for unit masonry products (bricks, stone, etc.), is required.

The choice of pedestal or drainage layer type is the responsibility of the design authority. Pedestals / drainage layers provide airflow for drying surfaces and assist in leveling. They should not impede the flow of water or air, and should uniformly distribute the dead load of pavers, and other unit masonry products, as well as predicted live loads.