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SikaSwell S-2 is a water-swelling polyurethane sealant for sealing non-moving concrete construction joints and penetrations. It expands when exposed to water and can also be used to fix SikaSwell A and P waterstop profiles to prepared concrete before casting.
Construction joint waterstopping
Use SikaSwell S-2 at correctly detailed horizontal or vertical concrete construction joints and around compatible pipe and steel penetrations. Its swelling action is reversible: the material contracts in dry conditions and expands again when water returns. Allow for the specified concrete cover and protect the uncured bead from premature wetting.
Important selection conditions
This is not a movement-joint sealant. The recommended water-pressure limit is up to 2 bar; above that, use it only as a supplementary waterstop. Swelling is slower and reduced in saline water. Reinforced concrete needs at least 80 mm cover on each side of the bead, and unreinforced concrete at least 150 mm. Concrete placement and compaction must prevent voids around the sealant.
Choose the appropriate bead size and allow the required curing period before the concrete pour. Detailed bead yields, temperature limits and profile-fixing conditions are provided in the product documents.
What is SikaSwell S-2 used for?
SikaSwell S-2 seals concrete construction joints and penetrations. It also bonds SikaSwell A and P Profiles to prepared concrete, and both uses rely on the same mechanism: contact with water makes the sealant swell and close the gap against water ingress.
How much does SikaSwell S-2 swell?
In tap water, volume change is less than 25% after 1 day and less than 100% after 7 days. Swelling in salty water is reduced and delayed compared with tap water.
Can SikaSwell S-2 be used for movement joints?
No. SikaSwell S-2 is excluded from movement-joint applications. Its documented uses are construction joints, concrete penetrations, and fixing SikaSwell A and P Profiles.
What water pressure can SikaSwell S-2 seal against?
SikaSwell S-2 is recommended for water pressures up to 2 bar. Above 2 bar, use it only as a supplementary joint sealing solution.
How long should SikaSwell S-2 cure before concrete is placed?
Allow at least 24 hours before placing concrete when bonding a SikaSwell profile. For pours above 50 cm, allow at least 3 days. Keep the sealant dry until the concrete is placed.
- Existing concrete: Sound, clean, and dry or matt damp. Remove loose particles, release agents, laitance, paint, rust, and other poorly adhering material.
- Freshly cast concrete: Smooth the placement area with a batten; excessively rough surfaces can be susceptible to leaking.
- Primer: Not required on concrete per the Product Data Sheet.
- Placement: Centre the sealant in the structure with the specified concrete cover on both sides.
Sika SikaSwell S-2 Physical Properties
| Property | Value |
|---|---|
| Composition | 1-part polyurethane, moisture curing |
| Colour | Oxide red |
| Packaging | 300 ml cartridges, 12 cartridges per box; 600 ml unipacs, 20 unipacs per box |
| Shelf Life | 9 months from date of production |
| Storage Temperature | +5 °C to +25 °C |
| Density | 1.24 kg/L at +23 °C |
| Shore A Hardness | 30–50, non-swollen after 7 days at +23 °C and 50% r.h. |
| Change Of Volume | <25% after 1 day in tap water, <100% after 7 days in tap water |
| Sag Flow | <2 mm at +23 °C and 50% r.h. |
| Substrate Moisture | Dry or matt damp |
| Curing Rate | ~2.0 mm after 1 day, ~10.0 mm after 10 days at +23 °C and 50% r.h. |
| Skinning Time | 60 minutes at +23 °C and 50% r.h. |
| Profile Placement Window | Maximum 30 minutes |
| Ambient Application Temperature | +5 °C to +35 °C |
| Substrate Application Temperature | +5 °C to +35 °C |
| Recommended Water Pressure | Up to 2 bar |
| Minimum Cover Reinforced Concrete | 8 cm on both sides |
| Minimum Cover Unreinforced Concrete | 15 cm on both sides |
| 12 mm Bead Yield | 4.1 m per 300 ml cartridge, 8.2 m per 600 ml unipac |
| 15 mm Bead Yield | 3.1 m per 300 ml cartridge, 6.2 m per 600 ml unipac |
| 20 mm Bead Yield | 1.8 m per 300 ml cartridge, 3.6 m per 600 ml unipac |