Xtra-Load Imperma Torch-on Tanking Membrane - Icopal

Xtra-Load Imperma Torch-on Tanking Membrane

Xtra-Load Imperma Torch On Tanking Membrane is suitable for use as a tanking membrane and as a damp proof membrane under tiled or grano floors in aggressive environments such as food factories, breweries and dairies. Using traditional hot bitumen or torch-on installation techniques, individual sheets are fused to the structure and to each other to ensure unbroken continuity of the seal.

Features & Benefits

  • High tensile strength.
  • High resistance to tearing.
  • Can be used on all types of wall construction.
  • Compatible with all forms of DPM’s and DPC’s.
  • Joints and seals easily.
  • High water vapour resistance.
  • British Board of Agrement Approved.

Product Range

Xtra-Load Imperma Torch-on Tanking is a polymer modified bitumen torch-on membrane with a strong polyester carrier. The upper surface is finished with a fine silica sand and the underside is finished with a thermofusible film. Xtra-Load Imperma is manufactured to include a special selvedge to improve bond strength at the laps.  

Product Code Description Roll Size Roll Weight
2001296 Xtra-Load Imperma Torch-on Tanking Membrane 8m x 1m 36kg


Product Data and Performance

Performance Data
Nominal Thickness: 4mm
Nominal Weight: 4.5kg/m-2
Tensile strength:

1000(1) \900(2) N/50mm



Water Penetration at joint: Nil

(1) Machine Direction  , (2) Transverse Direction

Resistance to Moisture: When completely sealed and consolidated Imperma SBS will meet Building Regulations requirements in the resistance of the passage of moisture from the ground. The membrane is impervious to water, and when correctly installed, will give a watertight layer capable of accepting designed structural movement without damage.

Resistance to Puncture: Provided sharp objects are not present prior to and during installation of the protective layer, the membrane will not be damaged by normal foot traffic.
Loading: When these heavy-duty membranes are fully confined they may be regarded as having the same compressive strength as the containing material.

Compatibility: Imperma SBS is compatible with concrete, smooth brick and blockwork, or screeded substrates, and are resistant to those chemicals with which they are likely to come into contact. However, care should be taken to prevent contact with mould oil and hydrocarbons.

Hydrocarbon solvent based products, such as Naphtha, paraffin and creosote will have a harmful effect and should not be allowed to come into contact with these membranes.

Surface Preparation

Imperma SBS, when fully protected and subjected to normal service conditions, will provide an effective barrier to the transmission of water and water vapour for the lifetime of the structure in which it is incorporated.

Properly applied, the membrane will achieve archive status in accordance with BS 8102:1990.

Installation Details

Imperma SBS heat bonded tanking membrane must be installed in accordance with the requirements of BS 8102: 1990.
Tanking should be externally applied wherever possible and immediately protected.
Imperma SBS membranes are applied by torch-on application using a standard roofer’s torch.

Preparation Of Surface: All surfaces should have a smooth finish, free from cavities, projections and mortar deposits. Surfaces should be dry and free from dust and frost. Concrete surfaces should be dense.

Vertical surfaces of brick and blockwork should be dry and rendered to provide an even surface. Brick or blockwork not rendered must be flush pointed to give a smooth surface without sudden changes in level.

Priming: Prior to application of the tanking membrane, a primary coat of Xtra-Seal QD Bitumen Primer must be applied to all surfaces and allowed to dry.

Angles And Corners: An angle reinforcement strip should be first torch-applied to all angles and corners. Reinforcing angles are formed by cutting a 300 mm strip of Imperma SBS from the roll.

Horizontal Application: Set out first roll as required, fully bonding by torching to the prepared substrate. Subsequent rolls should be set out with staggered end laps ensuring all joints have a minimum 100 mm overlap. Adjacent rolls should be applied in the same way ensuring side laps are a minimum 75 mm and follow the manufactured selvedge. Ensure there is a good flow of bitumen ahead of the sheet and a continuous extrusion bead of bitumen at the sides.
Roll back each roll halfway and fully bond the membrane to the substrate. Repeat for the second half of the roll.
Subsequent layers should be offset 300 mm from the first to avoid side build up. End laps should also be offset.
The surface of the membrane should be protected immediately by application of Xtra-Load Torch-On Protection Layer or a sand/cement screed.

Vertical Application: The Imperma tanking membrane should be cut to an appropriate length and, starting at the bottom, hot bonded to the upstands of the horizontally applied membrane, making sure that there is a good flow of bitumen ahead of the sheet and a continuous extrusion bead of bitumen at the sides. Allow a minimum 100mm overlap.
Next, working upwards, torch bond the membrane to the primed vertical surface. Subsequent rolls should be applied in the same way, ensuring side laps of 75 mm minimum. Where vertical drops require more than one length of membrane, ensure a minimum overlap of 150mm at horizontal joints. At the termination of vertical membrane, the uppermost end should be mechanically restrained with a predrilled fixing strap, or sealed into a chase.

Membrane Protection: On completion of installation, the Xtra-Load Imperma Torch On Tanking Membrane must be immediately protected with Xtra-Load Torch-on Protection Layer. A detailed inspection for damage and faults must be carried out before the tanking membrane is permanently covered. Applying,and fully heat bonding an additional layer of membrane should repair any faults.

Notes: Detailed consideration must be given to service penetrations unavoidably routed through tanked walls and floors; puddle flanges should be cast in where necessary. Imperma SBS may be carried across expansion joints provided sufficient care is taken at the detailing stage. 

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