STP ShaliBond EPDM
Solvent-based synthetic-rubber contact adhesive that locks EPDM sheet to concrete, metal and masonry for fully adhered, wind-resistant waterproofing systems.
What is it?
A single-component, solvent-based contact adhesive built on a synthetic-rubber base, engineered specifically to bond STP ShaliEPDM (EPDM rubber) waterproofing membrane to the deck below.
Where is it used?
Fully adhered EPDM roofing and lining on terraces, podiums, basements and pond bases, over concrete, metal and other prepared construction substrates.
Why use it?
It creates a continuous, high-strength bond across the whole membrane, so the sheet resists wind uplift and stays put on sloped, exposed and projection detailing where loose-laid systems struggle.
How is it applied?
Coat both the substrate and the membrane evenly by hard brush, trowel or roller, let each face flash off to a tacky state for about 10-15 minutes, then press the sheet down and consolidate with a metal roller.
About STP ShaliBond EPDM
STP ShaliBond EPDM is the companion adhesive to STP’s ShaliEPDM membrane, made for one job and made to do it well: holding an EPDM rubber sheet firmly to the surface underneath. It is a solvent-based, synthetic-rubber contact adhesive, which means it develops its grab as the solvent flashes off rather than by chemical cure. You wet out both mating faces, wait for the solvent to leave and the film to go tacky, then bring the two surfaces together. The result is an instant, high-tack bond across the entire contact area rather than a few mechanical fixings, which is exactly what a fully adhered roof needs to shrug off wind and stay dimensionally stable through India’s heat-and-monsoon cycle. Because it needs no primer on clean concrete, metal or masonry, it also keeps the site sequence short.
For engineers and applicators, the practical appeal is control and honesty about scope. This is not a waterproofing membrane in itself and not a splice adhesive for seams; it is the bonding layer that turns a loose EPDM sheet into a fully adhered system. STP publishes real working numbers for it, coverage of 1.23-2.03 square metres per litre applied to both surfaces, a 10-15 minute drying window and a 22 percent solids content, so quantities and programme time can be planned rather than guessed. Supplied in 20-litre pails through Space Arc Engineering, ShaliBond EPDM sits inside a coherent STP roofing kit alongside the ShaliEPDM membrane, splice tape for the laps and geotextile for protection, which is why specifiers who standardise on ShaliEPDM tend to specify this adhesive with it.
The technical insight
Contact adhesives work on a simple but unforgiving principle: the bond is built by the solvent leaving, not by anything hardening later. ShaliBond EPDM carries roughly 22 percent solids of synthetic rubber in a solvent carrier at a viscosity of 1700-2000 cps, thin enough to spread evenly with a brush or roller yet bodied enough to stay where it is put on a vertical upstand. When you coat both the EPDM sheet and the substrate and wait out the 10-15 minute drying window, the solvent evaporates and each surface is left with a thin, tacky, rubber-rich film. Rubber-to-rubber has a natural affinity, so when the two dried films meet under roller pressure they knit into a single continuous layer almost immediately, with no open time spent waiting for a cure. That is why the manufacturer stresses drying both faces to tack before contact and consolidating with a metal roller: the roller squeezes out trapped air and forces intimate film-to-film contact, which is where the real strength comes from. Coverage is quoted for both surfaces because both must be coated, and the 1.23-2.03 sqm/L range reflects the honest reality that a rough or porous deck drinks more adhesive than a smooth one. The low specific gravity of 0.86 and quick flash-off also mean the film builds grab fast in warm conditions, which suits the fully adhered detailing around drains, parapets and projections where you cannot rely on ballast to hold the sheet down.
Where it is used
- Fully adhered EPDM membrane roofing on exposed terraces and podium decks where wind uplift resistance matters
- Bonding ShaliEPDM sheet to basement walls and rafts as part of a below-grade waterproofing system
- Adhering EPDM lining to concrete pond, lake and water-body bases at golf courses and reservoirs
- Sticking EPDM sheet down over metal decks and roofs where a heat-free bonding method is required
- Dressing membrane onto upstands, parapets, kerbs and other concrete projections that loose-laid systems cannot secure
- Fixing EPDM around drain outlets and detailing points that need a continuous, air-free bond
- Re-roofing and refurbishment where an existing sound substrate is over-laid with a new fully adhered EPDM layer
- Cold-applied EPDM installations on occupied buildings where torch-on or hot works are not permitted
Key advantages
- Develops a strong, continuous bond across the whole sheet, giving fully adhered systems genuine wind-uplift resistance
- Cold-applied and heat-free, so it suits occupied roofs, fire-sensitive sites and no-hot-work conditions
- Needs no separate primer on clean concrete, metal or masonry, shortening the application sequence
- Fast 10-15 minute flash-off keeps the crew moving and lets bonded areas be trafficked sooner
- Spreads easily by hard brush, trowel or roller, so no specialist spray equipment is required
- Bonds EPDM to a range of substrates, from concrete decks to metal roofs and construction projections
- Published coverage of 1.23-2.03 sqm/L per two-surface application allows accurate quantity take-off
- Part of a matched STP ShaliEPDM system, reducing compatibility guesswork on membrane, tape and adhesive
Limitations & considerations
- Solvent-based and flammable, so it demands ventilation, PPE and strict no-flame discipline during application and storage
- It is a bonding adhesive only, not a waterproofing membrane, and cannot be used on its own to seal a roof
- Not the seam adhesive, EPDM-to-EPDM splice and lap joints require ShaliBond EPDM (S) or splice tape instead
- Both surfaces must be dry, clean and free of dust, grease, holes and undulations or the bond will fail
- Contact bonding is largely unforgiving once the tacky films meet, leaving little room to reposition the sheet
- Shelf life is limited to one year in a sealed pail, and warm storage or an opened drum shortens usable life
Selection & best practice
Start with the substrate: the deck and the underside of the EPDM sheet must be dry, sound and free of dust, grease, oil, loose material and sharp undulations, because a contact adhesive only bonds as well as the surface it grips. No primer is needed on clean concrete, metal or masonry. Spread ShaliBond EPDM evenly on both the substrate and the membrane using a hard brush, trowel or roller, keeping the film uniform and avoiding puddles or bare patches, and budget adhesive against the 1.23-2.03 sqm/L two-surface coverage, allowing the higher consumption on rough or porous decks. Let both coated faces flash off for about 10-15 minutes until they are tacky rather than wet to the touch; joining too early traps solvent and weakens the bond. Lay the sheet carefully, since repositioning is difficult once the tacky films touch, and press it down working out from the centre to expel air. Consolidate the whole area with a metal roller to force intimate contact and eliminate air pockets. Treat all EPDM-to-EPDM splice and lap joints separately with ShaliBond EPDM (S) or splice tape, and on trafficable roofs protect the finished membrane with a geotextile and a wearing layer. Keep pails sealed, cool and away from any flame, and use within the one-year shelf life.
Specifications
| Base | Synthetic rubber (solvent-based contact adhesive) |
| Colour | Yellowish |
| Solids content (by weight) | 22 ± 1 % |
| Viscosity | 1700 – 2000 cps |
| Specific gravity | 0.86 |
| Drying / flash-off time | 10 – 15 minutes |
| Coverage (both surfaces) | 1.23 – 2.03 sqm / litre |
| Packing | 20 litre pail |
| Shelf life | 1 year in sealed drum, cool and dry storage |
Industry use cases
Commercial and Industrial Roofing
Fully adhered EPDM roofing on large exposed terraces and factory decks, where continuous bonding delivers the wind-uplift resistance that loose-laid or ballasted systems cannot guarantee.
Basement and Below-Grade Waterproofing
Bonding ShaliEPDM to basement walls and rafts with wider 150 mm laps, giving a durable, chemically resistant barrier against ground water and hydrostatic pressure.
Water Retaining Structures
Adhering EPDM lining to concrete pond, lake and reservoir bases at golf courses and water-preservation ponds, where the membrane’s ozone and weather resistance suits long immersion.
Refurbishment and Re-roofing
Cold-applied bonding over sound existing substrates on occupied buildings, avoiding torch-on hot works and allowing bonded areas to be trafficked within a short flash-off window.
Detailing and Projections
Securing EPDM around parapets, kerbs, drain outlets and concrete projections, where a continuous adhesive bond holds the sheet in place at the very points loose-laid membranes tend to lift.
Frequently asked questions
What exactly is STP ShaliBond EPDM used for?
How much area does one 20-litre pail cover?
Does it need a primer before application?
How long should I wait before joining the surfaces?
Can I use it to seal the EPDM seams and laps?
Is it safe to use on occupied buildings?
How we position STP ShaliBond EPDM
STP ShaliBond EPDM is not a standalone product but the bonding layer of a matched STP roofing system, so it is best specified together with the STP ShaliEPDM membrane it is designed to adhere. Complete the system with ShaliBond EPDM (S) or STP splice tape for the EPDM-to-EPDM seams and laps, ShaliGeoText 300 GSM geotextile as a protection layer under trafficked finishes, and ShaliSeal PU GG polyurethane sealant for movement joints in the protective screed. Where a project instead calls for a self-adhesive HDPE or bituminous membrane rather than loose EPDM sheet, the requirement is a different waterproofing approach altogether, and brands such as Fosroc (Proofex and Fosroc Membrane HDPE range) or Dr. Fixit are more relevant than an EPDM contact adhesive. Space Arc supplies the full STP EPDM kit alongside these alternative systems, so we can match the adhesive, membrane and protection to what the specification actually demands.
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