STP ShaliTape Flex
A thermoplastic elastomer joint tape that seals wide, high-movement expansion joints while flexing in more than one direction without losing its watertight bond.
What is it?
A thermoplastic elastomer (TPE) sealing tape from STP Limited, bonded over expansion and movement joints with ShaliBond TPE adhesive to form a flexible, chemical-resistant watertight bridge.
Where is it used?
Expansion joints in tunnels, roads, hydraulic structures, precast panel joints, structural facades and flat-roof waterproofing details where the joint moves in several directions.
Why use it?
It accommodates large, irregular, multi-directional movement while staying sealed, and resists a long list of chemicals and effluents that would degrade ordinary sealant-only joints.
How is it applied?
ShaliBond TPE adhesive is brushed onto both prepared joint edges in two coats and the tape is embedded into the wet adhesive, leaving the central web loose to absorb movement.
About STP ShaliTape Flex
STP ShaliTape Flex is a purpose-made joint-sealing tape for the situations where a gun-applied sealant simply cannot keep up. Rather than filling a joint with an elastic compound, it bridges the gap with a strip of thermoplastic elastomer that is bonded only along its two edges. The loose central portion of the tape then acts as a flexible loop, free to stretch, compress and shear as the structure moves, which is why STP positions it for tunnels, bridge decks, precast panel joints, hydraulic works and other assemblies that see genuinely large and often multi-directional movement.
For engineers and applicators across Delhi NCR and the rest of India, the appeal is the combination of movement capacity and chemical durability in one detail. The tape is supplied in 100 mm and 200 mm widths and in 1 mm and 2 mm thicknesses, on 20 m rolls, so a specifier can match the strip to the joint width and the expected exposure. It is bonded with STP’s companion ShaliBond TPE adhesive, and because the whole system is engineered together, the bond line and the tape behave as a single, predictable unit rather than a field-improvised patch.
The technical insight
The performance comes from how the tape is fixed rather than from the tape alone. ShaliBond TPE adhesive is applied only across a defined bonding band on each side of the joint, roughly 20 mm each side for the 100 mm tape and 25 mm each side for the 200 mm tape, so the tape is anchored to sound concrete beyond the joint edges but left completely unbonded across the gap. That deliberately loose central web is what carries movement: when the joint opens the web straightens and takes up the extension, and when it closes the web folds, so the strain is spread over the free length instead of concentrating at a bond line. Because the material is a thermoplastic elastomer it returns after each cycle rather than taking a permanent set, giving the elastomeric, more-than-300-percent-class extensibility that lets it tolerate irregular, multi-axis movement. The same TPE chemistry gives the tape its broad resistance to water, cement-laden water, seawater, sewage, bitumen, diesel and light fuel oil, alkalis, acids and common solvents, so the seal survives the aggressive service conditions found in tunnels and hydraulic structures.
Where it is used
- Sealing structural expansion joints in road and rail tunnels
- Movement joints in dams, reservoirs, channels and other hydraulic works
- Joints between precast concrete panels and segmental linings
- Expansion joints in structural facades and building envelopes
- Wide movement-joint details in flat-roof waterproofing systems
- Sealing joints in effluent, sewage and water-treatment structures
- Remedial re-sealing of failed or under-designed expansion joints
- Joints exposed to fuels, oils or chemical spillage in industrial slabs
Key advantages
- Accommodates large, irregular movement in more than one direction
- Bonded-edge design concentrates strain in a free web, not at the joint arris
- Thermoplastic elastomer recovers after cycling instead of taking a set
- Broad chemical resistance to water, sewage, bitumen, fuels, acids and alkalis
- Tensile strength above 10 MPa gives a robust, tear-resistant seal
- Choice of 100 mm and 200 mm widths and 1 mm or 2 mm thickness to suit the joint
- Engineered as a system with ShaliBond TPE adhesive for a predictable bond
- Suited to demanding infrastructure such as tunnels, dams and treatment plants
Limitations & considerations
- Needs the companion ShaliBond TPE adhesive and correct surface priming; it is not a peel-and-stick tape
- Bond depends on clean, dry, sound substrate, so poor surface preparation will cause failure
- Rated for service roughly between minus 30 and plus 60 degrees Celsius, so it is not for very high-temperature exposure
- Two-coat adhesive application with a recoat window of about 3 to 18 hours demands trained labour and site discipline
- Designed for defined joint widths in the 40 to 60 mm range; very wide or very narrow joints need a different detail
- As a joint-bridging tape it complements, rather than replaces, the field waterproofing membrane
Selection & best practice
Detail the joint first: confirm the moving joint width falls within the recommended 40 to 60 mm band and select the tape width and thickness accordingly. Grind or wire-brush the two bonding bands back to sound, laitance-free concrete, then make sure the surface is clean, dry and dust-free and prime with the recommended STP primer to build bond strength. Apply ShaliBond TPE adhesive as a first coat only over the bonding bands, roughly 20 mm each side for 100 mm tape and 25 mm each side for 200 mm tape, then apply the second coat and lay the tape into it, keeping the central web deliberately loose over the joint and pressing the edges firmly to wet out the adhesive. Respect the recoat window between adhesive coats, of the order of a minimum of three hours and a maximum of eighteen, and protect the completed tape until the field membrane is dressed over it. On long runs, plan overlaps and terminations in advance so the seal stays continuous.
Specifications
| Material | Thermoplastic elastomer (TPE) joint tape |
| Available widths | 100 mm and 200 mm |
| Thickness | 1 mm and 2 mm |
| Roll length | 20 m |
| Tensile strength | Greater than 10 MPa |
| Service temperature | -30 degrees C to +60 degrees C |
| Companion adhesive | ShaliBond TPE, applied in 2 coats at approx. 800 g/m2 per coat |
| Adhesive bonding band | ~20 mm each side (100 mm tape); ~25 mm each side (200 mm tape) |
| Chemical resistance | Water, cement-water, seawater, sewage, bitumen, diesel, fuel oil, acids, alkalis, solvents |
Industry use cases
Tunnels & Metro
Seals segmental and expansion joints in road, rail and metro tunnels where the lining moves and the joint must stay watertight against groundwater.
Dams & Hydraulic Works
Bridges movement joints in dams, reservoirs, channels and intakes, holding a seal under sustained water pressure and wet-dry cycling.
Water & Effluent Treatment
Keeps expansion joints in tanks and treatment structures sealed against sewage, chemicals and aggressive effluents that attack ordinary sealants.
Precast & Facades
Handles the wide, multi-directional joints between precast panels and facade elements that open and shear with thermal and structural movement.
Roofing & Podiums
Forms the flexible movement-joint detail within flat-roof and podium waterproofing systems, tying into the surrounding membrane.
Frequently asked questions
Is ShaliTape Flex a self-adhesive tape?
How much movement can it handle?
What joint width is it suited to?
Which adhesive and how is it applied?
What chemicals and temperatures does it resist?
What sizes does Space Arc supply?
How we position STP ShaliTape Flex
ShaliTape Flex is the high-movement joint-bridging tape in STP’s waterproofing range and is best specified together with its companion STP ShaliBond TPE adhesive, which forms the actual bond and should always be ordered alongside it. It works within, not instead of, the field waterproofing, so pair it with STP liquid or membrane systems such as ShaliUrethane liquid membranes and the ShaliProtek range for the main deck or wall, using the tape only at the moving joints. Where a project instead calls for a gun-grade elastic sealant in a narrower, lower-movement joint, that is a different detail, and our Fosroc polyurethane joint sealants are the more suitable choice there. For sheet-membrane basements and tunnels, the STP membrane and Fosroc Proofex membrane families complement the tape rather than compete with it.
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