Product Data Sheet Show all documents
SikaShield® HB79 MG 4 mm

SikaShield® HB79 MG 4 mm

160 mils hybrid (SBS/APAO) bituminous cap sheet, torch-applied

SikaShield® HB79 MG 4 mm is a 2-in-1 modified bituminous roofing membrane with a thickness of 160 mils. The upper layer is APAO-modified (an APP polymer type), which provides excellent heat resistance and durability, while the under layer is SBS-modified, enhancing elongation, elasticity, and cold flexibility. It is reinforced with a dimensionally stable composite inlay of a fiberglass mat compressed between two layers of non-woven spunbond polyester fabric and remains flexible at -13°F (-25°C). The top surface is coated with mineral granules, which allows the permanent exposure to UV radiation. 

  • Combines the advantages of APAO and SBS bitumen
  • High durability 
  • Thicker membrane
  • Highly flexible at low temperatures
  • High heat resistance
  • High impact and shear resistance
  • Excellent fatigue strength
  • Can be installed by torch, mop, cold adhesion or mechanical fixation
  • Fully bonded
  • Can be coated immediately after application
  • Tiles can be placed directly onto the membrane
  
Product Data Sheet Show all documents

Usage

The Product is used as a roof membrane for:
  • Flat or sloped roofs with up to 15% gradient
  • Balconies and terraces
 

Advantages

  • Combines the advantages of APAO and SBS bitumen
  • High durability 
  • Thicker membrane
  • Highly flexible at low temperatures
  • High heat resistance
  • High impact and shear resistance
  • Excellent fatigue strength
  • Can be installed by torch, mop, cold adhesion or mechanical fixation
  • Fully bonded
  • Can be coated immediately after application
  • Tiles can be placed directly onto the membrane
  

Packaging

Roll width

39.4" (1.0 m)

Roll length

32.8 ft (10 m)

Product Details

Sustainability / Certifications / Approvals

APPROVALS / STANDARDS

  • Meets or exceeds the ASTM D6163, Type I, Grade G
  • Underwriters Laboratory (UL)
  • FM Global
  • CRRC
  • SikaShield® Pure-Air is certified according to the Photocatalytic Performance ISO 22197-1, D-tox, Nr. 25062020

 
Product Information

Chemical Base

Top layer

APAO modified bitumen

Bottom layer

SBS modified bitumen

Reinforcing Material

Composite inlay of a fiberglass matt compressed between two layers of non-woven spunbond polyester fabric

Shelf Life

36 months from the date of production

Storage Conditions

The Product must be stored in original unopened and undamaged packaging in dry conditions and temperatures between 41°F (5°C) and 95°F (35°C). Store in a vertical position. Do not stack pallets of the rolls on top of each other, or under pallets of any other materials during transport or storage. Always refer to packaging.

Top surface

Mineral Granules:

  • Regular white
  • High Reflective White
  • Pure-Air (Smog Reduction)
  • Other colors: grey, green, black, red, blue

Bottom Surface

Polyethylene burn-off foil

Effective Thickness

160 mils (4.0 mm) on the selvage edge

(ASTM D5147)

Weight

126 pounds per roll
Technical Information

Hail Resistance

Pass class SH

(FM Global)

Tensile Strength

Longitudinal (MD)

81 lbf/in

Transversal (CMD)

73 lbf/in

Elongation

Longitudinal (MD)

53 %

Transversal (CMD)

58 %

Dimensional Stability

Longitudinal

0.0 %

Transversal

0.1 %

Tear Strength

Longitudinal (MD)

149 lbf

Transversal (CMD)

119 lbf

Joint Shear Resistance

Longitudinal

74.23 lbf/in  (650 N/50 mm) 

Transversal

68.21 lbf/in  (550 N/50 mm) 

External Fire Performance

Class A

(UL 790)

Behavior after Artificial Weathering

Flexibility at low temperature after heat conditioned at 70 °C

-13 °F (-25 °C)

Solar Reflectance

Initial

3-year

0.68

0.61

Thermal Emittance

Initial

3-year

0.89

0.89

Solar Reflectance Index

Initial

3-year

82

73

Durability

Loss of granules

0.1 gr

Low Temperature Bend

-13 °F (-25 °C)

(ASTM D5147)

Application

Application Information

Ambient Air Temperature

Minimum

 41°F (5°C)

Maximum

 104°F (40°C)

Relative Air Humidity

Maximum 80%

Substrate Temperature

Minimum

41°F (5°C)

Maximum

104°F (40°C)
Application steps

SUBSTRATE QUALITY

  • The supporting structure must be of sufficient structural strength to support all new and existing layers of the system build-up.
  • If used as a roof system, the complete system must be designed to withstand and be secured against wind uplift loadings.
  • The substrate surface must be uniform, firm, smooth and free of any sharp protrusion or burrs, clean, dry, free of grease, laitance, oil, dust and loosely adhering particles.

APPLICATION

To avoid coinciding joints, lay the membranes parallel to one another, align it properly, ensure the specified overlaps are followed, and then re-roll it before application.

                   

MEMBRANE OVERLAPS

       

  • Overlap the membranes by a minimum of 4" (100 mm) on the sides and 6" (150 mm) on each end. 
  • At the end overlap, cut off a corner measuring 4" (100 mm) per side at an angle of 45°.
  • End laps must be staggered 18'' (46 cm) apart.
  • Offset cap sheet side and end laps so they are positioned at least 12'' (28 cm) away from any base ply laps.
  • A mininum 20 lb (9 kg) roller must be used on all side and end laps, following immediately behind the heat welding. Apply uniform pressure across the lap area while the bituminous compound is warm to ensure a positive bond.
  • A continuous bead of asphalt approximately 1/4 inch wide should be visible at all laps after application.
  • The edge of the seam must be left untooled (not buttered).

 

IMPORTANT: DO NOT STACK LAPS!

            

 

TORCHING

 

  1. Heat the substrate and the backing film on the underside of the membrane with a gas burner.
  2. When the backing film starts to melt, the membrane is ready to stick.
  3. Roll the heated membrane forward and press it firmly against the substrate to bond it.
  4. Make sure a bead of melted bitumen is visible along the full length of the overlap sides and ends when laying.

                        

Suitable substrates for torching:

 

  • Concrete
  • Gypsum coverboard
  • Perlite screed
  • Bituminous membranes with a smooth surface
  • Coatings (check the compatibility)
  • Brick masonry
  • Cementitious screeds            

 

DETAILING

      

Use a sharp knife to cut in all details such as internal and external corners, upstands, vent pipes, drains, support metalwork etc.

   

Refer to the relevant method statement for further information on detailing.

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