Sika MultiSeal AP
Self-adhesive, aluminium-faced bituminous tape that seals roof laps, gutters, flashings and penetrations without heat, primer or mixing on most surfaces.
What is it?
A self-adhesive, rubber-modified bituminous sealing tape faced with aluminium foil, roughly 1.1 mm thick and 100 mm wide, supplied in 3 m and 10 m rolls.
Where is it used?
Roof sheet-metal laps, leaking gutters, chimneys, roof lights, vent and duct penetrations, facades, broken tiles, containers, caravans and trailers.
Why use it?
It gives an instant cold-applied watertight seal on most clean, dry substrates with no torch, primer or mixing, and its foil face resists weather and UV.
How is it applied?
Prepare the surface, cut to length, peel the release film and firmly roller the tape down; overlap joints by at least 50 mm.
About Sika MultiSeal AP
Sika MultiSeal AP is Sika’s ready-to-use answer to the small but stubborn leaks that show up on almost every roof and facade: a lap that has lifted, a gutter joint weeping at the seam, a flashing that pulled away from a chimney, a cracked tile, a vent penetration that was never properly detailed. It is a self-adhesive tape built from a rubber-modified bituminous compound and laminated on the upper face with an aluminium foil. The bitumen side grips the substrate and stays flexible; the foil side takes the weather and the UV, and can be over-painted to blend with the surrounding finish. For a site team, that combination means a permanent watertight repair can be made in minutes with a knife and a roller, without a gas torch, without a primer on most surfaces, and without any on-site mixing.
For a distributor-and-applicator like Space Arc working across Delhi NCR and Pan-India, MultiSeal AP earns its place because it closes the gap between a full membrane system and a tube of sealant. It is faster and cleaner than torching a patch of membrane onto a hot roof, and it holds up far better than mastic on a lap that flexes and moves. It bonds to metal, most plastics, coated surfaces, glazed tiles and bituminous substrates, and it can be applied at low ambient temperatures when other cold-applied products struggle. Supplied 100 mm wide in 3 m and 10 m rolls, it is equally at home in a maintenance kit for reactive roof repairs and in a contractor’s toolbox for detailing new sheet-metal roofing, gutters and penetrations.
The technical insight
The tape works because it is really two engineered layers doing two different jobs. The lower layer is a rubber-modified bitumen: bitumen supplies the tack and the low-temperature adhesion, while the rubber modification keeps it flexible and lets it stretch and recover as the joint moves under thermal cycling instead of cracking like plain bitumen mastic would. That elasticity is why the tape survives on laps and flashings that expand and contract every day. The upper layer is an aluminium foil laminate, and its role is protective rather than adhesive: it shields the bitumen from UV and weathering (the usual reason cheap bituminous repairs go brittle and fail), reflects heat, and gives an over-paintable surface. Adhesion is a cold pressure-sensitive bond, so pressing firmly with a roller is what actually creates the seal by wetting the bitumen onto the substrate and driving out trapped air. On slick non-porous surfaces the compound needs a chemically clean, activated substrate to grip, and on porous surfaces it needs a bituminous primer to stop the open pores from wicking moisture under the tape, which is why surface preparation, not the tape itself, decides whether the repair lasts.
Where it is used
- Sealing overlaps and laps in metal roof sheeting and cladding
- Repairing leaking roof gutters, valleys and drainage channels
- Weatherproofing flashings around chimneys, parapets and roof lights
- Detailing vent, pipe and duct penetrations through roofs
- Patching cracked or broken roof tiles and localised roof defects
- Sealing joints and seams on facades and rainscreen details
- Waterproof repairs on containers, portable cabins, caravans and trailers
- Sealing seams on ductwork and sheet-metal fabrications
Key advantages
- Cold-applied and self-adhesive, so no gas torch, flame or hot works are needed
- No primer or mixing required on most dry, clean, sound substrates
- Instant watertight bond that is ready to weather immediately
- Aluminium foil face resists UV and weathering and can be over-painted
- Rubber-modified bitumen stays flexible and accommodates joint movement
- Bonds well to metal, most plastics, coated surfaces, glazed tiles and bitumen
- Can be applied at low ambient temperatures, extending the working season
- Fast, clean and low-skill to apply, cutting labour on small repairs
Limitations & considerations
- Not suitable for joints under water pressure or permanent water immersion
- Must not be used on natural stone substrates
- Should not be over-painted with solvent-based paints
- Porous substrates require a bituminous primer or water can track under the tape
- Not recommended for overhead application when service temperatures exceed +25 C
- Direct contact with other joint sealants and adhesives must be avoided or compatibility pre-tested
Selection & best practice
Adhesion is decided before the tape ever comes off the roll, so treat surface preparation as the main task. The substrate must be stable, clean, dry and free of dust, oil, grease, laitance, old sealant and poorly bonded paint; remove loose material by wire brushing, grinding or sanding. On non-porous surfaces such as metals, plastics, coated surfaces and glazed tiles, wipe with Sika Aktivator-205 and allow a flash-off of more than 15 minutes (and under 6 hours) before sealing. On porous surfaces such as concrete, brick and cementitious plasters or mortars, prime with a bituminous primer like SikaShield Primer and allow at least an hour of flash-off. Work only when both air and substrate are between +5 C and +45 C, with the substrate at least 3 C above the dew point so no condensation film forms. Cut to length, peel the release film and press the tape down firmly with a roller to wet out the bitumen; overlap adjoining pieces by at least 50 mm. Warming the tape slightly during application improves the bond, and the foil face can then be over-painted with most conventional (non solvent-based) paint systems.
Specifications
| Chemical base | Rubber-modified bituminous tape with aluminium foil facing |
| Tape width | 100 mm |
| Thickness | 1.1 mm approx. |
| Roll lengths | 3 m (12 rolls/box) and 10 m (3 rolls/box) |
| Colour | Matt grey, Terracotta |
| Tensile strength | Greater than or equal to 130 N/25 mm (ASTM D1000) |
| Elongation at break | Greater than or equal to 80% (ASTM D1000) |
| Service temperature | -20 C to +80 C |
| Application temperature | +5 C to +45 C ambient and substrate; min. 3 C above dew point |
Industry use cases
Industrial & Warehouse Roofing
Sealing sheet-metal laps, ridge details and fastener lines on large profiled metal roofs, and stopping recurring leaks at gutters and valleys without shutting operations for hot works.
Facility Maintenance
A fast reactive-repair tape for building maintenance teams to close leaks at flashings, roof lights, penetrations and cracked tiles between planned waterproofing cycles.
Commercial & Retail Fit-out
Weatherproofing roof penetrations for new HVAC, exhaust ducts and services, and detailing facade seams where a clean over-paintable finish matters.
Portable & Modular Structures
Sealing seams and joints on site containers, portacabins, caravans and trailers, where a cold self-adhesive repair is safer and quicker than flame-applied products.
HVAC & Sheet-Metal Ducting
Sealing longitudinal and lap seams on ductwork and sheet-metal fabrications to give a durable, foil-faced weatherproof joint.
Frequently asked questions
Do I need a primer to use Sika MultiSeal AP?
Can I paint over the tape to match my roof or facade?
Will it hold up to ponding water or waterproof a structure under pressure?
What widths and roll lengths are available?
What is the temperature window for applying and using it?
How should the tape be stored and how long does it last?
How we position Sika MultiSeal AP
Sika MultiSeal AP sits in Space Arc’s sealing and joint-treatment range as the go-to for fast, cold-applied roof and flashing repairs. It pairs naturally with the wider Sika roof and repair family: use Sika Aktivator-205 to prepare metal, plastic and glazed surfaces, and a bituminous primer such as SikaShield Primer on porous substrates before taping. Where the leak is bigger than a lap or penetration and calls for a fully bonded membrane, step up to a torch- or self-applied SikaShield/Sika bituminous membrane system rather than tape. For gun-grade sealing of the same flashings and gutter laps, Sikaflex and rubber-bitumen mastics from our range complement the tape. Across our other brands, Dr. Fixit and Fosroc offer comparable roof-repair mastics and self-adhesive flashing solutions where a specifier already standardises on those systems; our team can match the tape to whatever primer, mastic or membrane the rest of the detail uses.
Fosroc Nitoseal MB175 — Choose the Fosroc gun-grade rubber-bitumen mastic when the flashing or gutter-lap detail needs a tooled, moulded sealant bead rather than a self-adhesive tape, or when the project already standardises on the Fosroc bituminous roofing system.
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