Not sure on how much sealant you'll need? Use our calculator to find out.
For movement and connection joints on porous substrates and general indoor or outdoor sealing, Sikaflex Construction AP+ provides a flexible, moisture-curing barrier. This polyurethane sealant manages joint movement on high-exposure facades, concrete structures, and metal connections without sagging or losing its seal.
Sikaflex Construction AP+ cures on exposure to atmospheric moisture to form a tough, elastic joint sealant. The polyurethane chemistry delivers non-sag performance on vertical and soffit joints up to 30 mm wide, preventing the wet sealant from slumping out of overhead or wall joints before it cures. It cures at approximately 3 mm per 24 hours, giving installers a long 160-minute tooling window to neat-finish the joint. The neutral, non-corrosive formulation will not degrade metal substrates like aluminium, stainless steel, or galvanised steel. Once fully cured, the sealant can be painted over with most conventional facade coating systems, though non-flexible paints may crack if the joint moves.
Sikaflex Construction AP+ adheres to both porous and non-porous building substrates, including:
All substrates must be clean, dry, sound, and free from oils, grease, dust, and loose particles. While the sealant adheres without primers for standard applications, critical or highly stressed joints require the following pre-treatments:
Sikaflex Construction AP is designed for movement and connection joints in construction, particularly on porous substrates. It accommodates joint widths from 10 mm to 40 mm with a recommended 2:1 width-to-depth ratio for optimal performance and durability.
Yes, it can be painted over with many conventional facade coating paint systems. For best results, allow the sealant to fully cure first. Note that non-flexible paint systems may crack due to the sealant's inherent elasticity and movement capability.
No, Sikaflex Construction AP is not recommended for use on natural stone. It is also not for use on bituminous substrates, natural rubber, EPDM, or materials that may bleed oils or plasticizers.
Sikaflex Construction AP offers a movement capability of ±25%, as tested to ISO 9047 and ASTM C 719 standards. This ensures the joint remains sealed even with significant structural movement.
| Application | Key benefit | Primary trades |
|---|---|---|
| Movement joints in concrete & masonry facades | Withstands ±25% joint movement, preventing cracking and water ingress. | Concrete contractors, facade installers, builders |
| General perimeter sealing on porous substrates | Provides reliable adhesion and durable weather resistance on common building materials. | General builders, renovators, maintenance crews |
| Vertical and soffit joint sealing up to 30 mm width | Non-sag properties ensure the sealant stays in place without slump during application. | Facade installers, mastic men, concrete repairers |
| Joints requiring over-painting for aesthetic finish | Compatible with many paint systems, allowing for a seamless, uniform surface appearance. | Painters, builders, facade specialists |
Ensure substrates are sound, dry, and free from dust, oil, grease, laitance, and loose coatings. Mechanically clean where necessary and repair damaged arrises.
Wire brush, grind, or grit blast to remove weak layers. Vacuum to remove dust.
Prime per substrate: porous (Primer-3 N), selected metals (Aktivator-205 ± Primer-3 N), PVC (Primer-215). Avoid puddling.
Insert closed-cell polyethylene backing rod to regulate sealant depth and provide a bond-breaker.
Target width:depth of 1:0.5 (≥8 mm depth; 8–40 mm width typical).
Target width:depth ~1:0.8 with robust edge preparation.
Cut nozzle to suit joint width. Gun sealant ensuring full sidewall contact and no air entrapment. Tool firmly for a dense surface.
Use a compatible, non-solvent tooling agent; avoid solvent-containing fluids.
Clean equipment immediately after use; cured material requires mechanical removal.
Sikaflex Construction AP is not classified as a hazardous substance or mixture. However, standard precautions should be followed.
Chemical-resistant, impervious gloves (butyl rubber/nitrile rubber recommended) and safety glasses are recommended. Inadequate ventilation may require respiratory protection.
Use adequate ventilation to prevent exposure to vapours. Local exhaust ventilation may be required in enclosed spaces.
Store in dry conditions, protected from direct sunlight, at temperatures between +5 °C and +25 °C. Shelf life is 12 months from production in original, unopened packaging. Dispose of waste via a licensed waste management company; do not contaminate waterways.
Proper surface preparation and priming are critical for ensuring optimal adhesion and long-term joint performance. Primers improve adhesion but are not a substitute for proper cleaning or surface strength.
Surface prep: Ensure the surface is clean, dry, sound, and free from oils, grease, dust, and loose particles.
Primer: Required. Apply Sika® Primer-3 N with a brush. Allow a flash-off time of 30 minutes to 8 hours before sealing.
Surface prep: Clean and degrease thoroughly. Surfaces must be dry and free from contaminants.
Primer: Optional. For critical applications, use Sika® Aktivator-205 wiped on with a clean towel. Allow a flash-off time of 15 minutes to 6 hours.
Surface prep: Clean and degrease thoroughly.
Primer: Required. First, pre-treat with Sika® Aktivator-205 (wiped on), then after flash-off, apply Sika® Primer-3 N with a brush. Allow 30 minutes to 8 hours flash-off before sealing.
Surface prep: Clean the surface to remove any contaminants.
Primer: Required. Apply Sika® Primer-215 with a brush. Allow a flash-off time of 30 minutes to 8 hours before sealing.
| Property | Value |
|---|---|
| Composition | Polyurethane |
| Packaging | 600 ml foil pack |
| Shelf Life | 12 months from production |
| Storage Conditions | Dry, protected from direct sunlight, +5 °C to +25 °C |
| Colour Options | Concrete Grey, Black, White |
| Density | 1.25 kg/l approx. |
| Shore A Hardness | 24 approx. (after 28 days) |
| Secant Tensile Modulus at 100% Elongation (23 °C) | 0.35 N/mm2 approx. |
| Secant Tensile Modulus at 100% Elongation (-20 °C) | 0.50 N/mm2 approx. |
| Tensile Strain at Break | 700% approx. |
| Movement Capability | ±25% (ISO 9047, ASTM C 719) |
| Elastic Recovery | 90% approx. |
| Tear Propagation Resistance | 5.0 N/mm approx. |
| Service Temperature | −40 °C to +70 °C |
| Joint Width Range | 10 mm to 40 mm |
| Recommended Width to Depth Ratio | 2:1 |
| Sag Flow | 0 mm (20 mm profile, 50 °C) |
| Ambient Air Temperature for Application | +5 °C to +40 °C (min. 3 °C above dew point) |
| Substrate Temperature for Application | +5 °C to +40 °C |
| Curing Rate | 3 mm/24 hours approx. (23 °C / 50% r.h.) |
| Skinning Time | 180 minutes approx. (23 °C / 50% r.h.) |
| Tooling Time | 160 minutes approx. (23 °C / 50% r.h.) |
| VOC Content | 3% w/w (SDS) |
Here are some common examples on where Sikaflex Construction AP+ Polyurethane Sealant used by our customers.
