BMC R1B-A

Single Layer Protected Bituminous Roofing System (Fully Bonded)


Download PDF

Description:

This roofing assembly consists of single layer modified bituminous waterproofing membrane fully bonded over the primed sand cement screed and covered by extruded polystyrene insulation board followed by separation layer and finishing layer of pre-cast concrete pavers or gravel.

Features and Benefits:

■    The membrane is maintained at a nearly constant temperature, close to the temperature of the building's interior; this minimizes the stresses on the membrane by reducing the harmful effects of thermal cycling and excessive heat.

■    The waterproofing membrane is protected from weathering, foot traffic and other types of physical abuse - both during and after construction.

■    Allow year-round construction since the roof is waterproofed first, then insulated.

■    Permit easily removal and re-installation of the ballast and insulation for making repairs or for constructing additional stories. In addition, a protected membrane roof provides an environmentally preferred option to reuse the insulation.

■    Allow for a range of ballast options - stones, precast paving slabs, green roof, interlocking stone or concrete - depending on use and aesthetic considerations.

■    Eliminate the need for a separate vapor retarder.

■    It offers exceptional durability to extend the life of the plaza or roof.

 

Installation Guidelines:

Sand cement screed laid to falls and cross falls (minimum 1% slope) trowel-applied smoothly finish.

The concrete surface to be waterproofed shall be dry and completely cleaned to remove any contamination from dust, sand, dirt, oil or grease, loose aggregate and debris etc.

Concrete upstands shall be dry, clean and smoothly finished; CMU (concrete Masonry Units) upstands must be properly plastered smoothly finished.

Where the membrane is to be fixed, the surface shall be primed using a solvent based bituminous primer conforming to ASTM D- 41, and left to dry.

Install single layer of bituminous torch-applied waterproofing membrane, the membrane should first be unrolled and position correctly. Each roll should overlap the adjacent roll by 100mm wide at side overlaps and 150mm staggered on end laps.

The membrane should be rolled up again, taking care not to change its orientation. Using left to right movements, heat the lower surface of the membrane with a propane gas torch.

Then torch on the side overlap to the recommended size of 100mm. continue the above mentioned for consecutive rolls remembering end-laps must be minimum of 150mm.

This operation is repeated until the entire surface is covered/waterproofed.

Options for Membrane Termination:

The waterproofing membrane ends shall be terminated minimum of 150mm above roof finishing level into performed grooved 20mm x 20mm & sealed with bituminous sealant; or

Terminated aluminum flashing bar mechanically fastened at 300 O.C. and completely sealed with bituminous sealant; or

Terminated into performed groove, sealed with bituminous sealant followed by installation of aluminum flashing bar mechanically fastened at 300 O.C. and sealed with bituminous sealant.

Water Test:

The water test can be done with flood testing. Minimum water head level and duration of the water test as per project requirements and engineer's instruction must be followed.

Plug the drains and provide necessary barriers to contain flood water to avoid pressure and damage the membrane.

Removal of water and cleaning/drying of the tested area must be done after the water test is completed.

Thermal Insulation:

Apply extruded polystyrene rigid board thermal insulation, loose laid with rebated edges over the completed and water tested waterproofing membrane system.

Separation Layer:

Apply a layer of non-woven geotextile separation layer with minimum of 100mm wide overlaps, loosely laid, above the installed waterproofing membrane, minimum of 50mm wide overlaps to the adjacent sheets.

Finishing Items:

Application of finishing items above the separation layer (i.e.: Pre­cast Concrete Pavers / Gravel) shall be provided & installed as project specification requirements.

Storage Conditions:

Products must be stored in their original packaging under cool and dry conditions. They must be protected from direct sunlight & rain.

Primers and sealants should be stored in a cool shaded storage or in air-conditioned containers.

Criteria

System Property

Membrane

Membrane Options

SBS/APP

Application Type

Torch-on Membrane Fully Bonded

Membrane Finishes

PE Film / Mineral Slates / Sand /

Aluminum

Reinforcements Options (g/m2)

180 / 200 / 250 / 270

Roll Size (W x L)

1m x 10m

Primer

Type of Primer

Bituminous Primer (Complying to ASTM D41)

Insulation

Insulation Type

Extruded Polystyrene Insulation Board

Density Options (kg/m3)

32-35/36 / 40 / 45 / 48

Thickness

Variable, As Per Project Requirements

Separation Layer

Separation Layer Options

Non-Woven Polyester or Polypropylene Geotextiles / Polyethylene Sheets

Separation Layer Density

Options

Variable, As per Project Requirements

Finishing

Finishing’s Options

Pre-cast Concrete Pavers / Gravels