Soudal Soudafoam 2K - Two-Component Fast Curing Expanding Foam

Health & Safety Recommendations

Read the product label and Safety Data Sheet before use and follow all site safety procedures for aerosol products and polyurethane foams. Use only in well-ventilated areas and avoid breathing vapours or aerosol mist, particularly in confined spaces such as small rooms, cupboards, lofts and service voids. Wear suitable gloves and goggles as a minimum, and use appropriate respiratory protection where ventilation is limited or where other trades are present. Keep away from heat, sparks and naked flames, and do not smoke during use.

Take the usual labour hygiene into account and prevent contact with skin and eyes. If splashes occur, wash immediately with plenty of clean water and seek medical advice if irritation persists. When vapourising product, for example with a compressor, additional safety measures are required. Keep the can upright in storage, protect from direct sunlight and high temperatures, and keep out of reach of children. Cured foam must never be burned away. Remove cured foam mechanically, using Soudal Cured PU Foam Remover to assist where appropriate.

Substrate Suitability

Soudal Soudafoam 2K is suitable for gap filling, sealing and installation work on most common construction materials, provided the surface is sound and stable. Typical suitable substrates include brick, block, concrete, stone, plaster, timber, many metals and many rigid plastics used in building work. It adheres well without primer in many situations, but performance depends on the condition of the substrate and the cleanliness of the bond faces.

The product is not suitable for PE, PP or PTFE. Care is also required on sensitive plastics, painted coatings and lacquered finishes because cleaning solvents and foam residues can mark or soften some surfaces. Where the foam will be visible or where finishes are critical, protect adjacent areas before application and carry out a small compatibility test first.

Surface Preparation

Ensure all surfaces are structurally sound and free from dust, loose particles, grease and release agents. Remove any friable mortar, flaking coatings or unstable residues that could prevent adhesion. Where surfaces are particularly dusty, brush and vacuum thoroughly so the foam can bond to the substrate rather than to loose contamination.

Dry-fit and secure the items being installed before activating the can. This is especially important for door and window fitting, because Soudafoam 2K must be used promptly once mixed, and frames should already be aligned, packed and mechanically fixed where required. Mask and protect adjacent surfaces with tape and sheeting if there is any risk of overspray or squeeze-out onto visible faces.

Application Method

Bring the can to the recommended temperature range before use, ideally 10°C to 25°C, to support consistent mixing, flow and yield. Confirm ambient temperature is within +5°C to +30°C and surface temperature is within +5°C to +35°C. Make sure the door or window frame is positioned correctly before activating, as the working time after activation is limited.

To activate, turn the black disc on the bottom of the can 5 times to the right to release the hardener. Shake the can firmly for at least 20 shakes with the valve pointed down to ensure the 2 components mix properly. Fit the supplied applicator to the valve, keep the valve pointed downwards, and dispense the foam. The extruded foam should be a solid, light green colour. If the colour is not uniform, repeat activation and shaking until the mixed foam colour is consistent.

Apply the foam carefully into the joint or cavity, filling to around 1/3 depth because the foam expands further during curing. Apply in a controlled bead to avoid overfilling and reduce clean-up. If working around frames, apply in stages as required, maintaining alignment and allowing expansion space so the foam does not distort the installation. To avoid curing inside the can, it is imperative to completely empty the can within 5 minutes after mixing the components.

Coverage

Coverage varies with joint size, application technique and substrate profile. As a practical guide, a 400ml can yields approximately 10L of foam (box yield) and provides approximately 8m of joint yield under EN 17333-1 test conditions. Wider or deeper voids will reduce linear coverage, while narrow gaps and well-controlled beads will increase the metres achieved.

Because Soudafoam 2K expands significantly during curing, plan the application to minimise waste by filling only to around 1/3 of the joint depth, then allowing the foam to expand and complete the fill. For large cavities, work in controlled sections to avoid excessive expansion and to maintain clean, even results.

Curing Time

Soudafoam 2K cures by polymerisation using the integrated hardener, so it does not require moisture to set. Skin formation is approximately 9 minutes and cutting time is approximately 15 minutes under typical conditions. A 30mm foam bead is fully loadable after approximately 4 hours, although lower temperatures, reduced ventilation or thicker applications can extend these times.

During curing the foam expands by approximately 192%, which is why joints should not be filled fully at application stage. Once cured there is no further expansion after curing, helping maintain dimensional stability around frames and in static joints. Where the foam will be covered, trimmed or sealed, allow it to cure sufficiently so it is firm and stable before proceeding.

Cleaning

Immediately remove spilled or uncured foam using Soudafoam Gun & Foam Cleaner. Before using any cleaner, test on an inconspicuous area to confirm the surface is not affected, especially on plastics and lacquered or painted surfaces. Use masking to prevent accidental contact with cleaners or foam on finished faces.

Cured foam must be removed mechanically. Where assistance is required, use Soudal Cured PU Foam Remover to help release cured residues, then scrape carefully without damaging the substrate. Clean-up is always easiest while the foam is fresh, so keep wipes and cleaning materials available during application and deal with overspill straight away.

Limitations

Soudafoam 2K is not UV-resistant and must be protected from sunlight after curing. Where exposed, cover the foam by overpainting, sealing with suitable sealants, applying render or plaster, or installing a physical cover strip as appropriate to the detail. Do not use on PE, PP or PTFE, and avoid use where movement joints require a tested elastic sealant rather than a rigid foam fill.

The product must be used immediately after activation and the can must be emptied within 5 minutes. This limited application window means it is not suitable for slow, stop-start work. Do not burn away cured foam. Do not use in areas where fire stopping is required unless the specific application is covered by the correct fire-rated system and certification for the detail being installed.

Other Information

Soudafoam 2K is a very low emission product, carrying the EC1 PLUS label, which supports use in occupied buildings where indoor air quality is a consideration, provided good ventilation is maintained during application and curing. The cured foam provides strong mechanical performance for typical installation work, including compressive strength of approximately 91kPa and tensile strength of approximately 212kPa, alongside effective insulation properties with thermal conductivity of 0.034W/m.K and acoustic performance of 63dB.

For best results, plan the job so all preparation is completed before activation, including dry-fitting, masking and access arrangements. Apply with care, allow for expansion, and protect the cured foam from UV exposure as part of the final detailing. Where the application is safety-critical, such as around escape doors, compartment lines or service penetrations, ensure the overall specification is suitable for the required performance standard rather than relying on foam alone.

Q) What is Soudal Soudafoam 2K – Two-Component Fast Curing Expanding Foam used for?

A) Soudal Soudafoam 2K is a ready-to-use polyurethane foam designed for rapid fixing, filling and sealing where a predictable cure and fast handling are essential. It is especially useful for fitting door and window frames, filling cavities, sealing gaps, and making good during renovation work where time is tight. Because it is two-component, it cures by internal polymerisation rather than relying on moisture in the air or substrate, which helps it set consistently in dry conditions and enclosed voids. Once cured it forms a dense, strong foam with excellent stability, no post-expansion and minimal shrinkage, supporting clean results and reducing the risk of movement after trimming.

Q) How is Soudafoam 2K different from standard one-component expanding foams?

A) The key difference is how it cures. Standard one-component foams rely on moisture to cure, so they can be slower or less predictable in dry air, on dry substrates, or in deeper voids where moisture penetration is limited. Soudal Soudafoam 2K cures through an internal chemical reaction using a second component released inside the can, so the set is more consistent and less dependent on site humidity. This makes it well suited to time critical installation work. It also offers strong dimensional control, with no post-expansion and minimal shrinkage, which is valuable around frames where late movement can affect alignment and sealing quality.

Q) When should I choose Soudal Soudafoam 2K instead of a moisture-cure foam?

A) Choose Soudal Soudafoam 2K when you need speed, predictable curing and dimensional control. It is a strong option for fitting doors and windows, refurbishment work with tight programmes, or any job where you want early trimming and early progression to the next trade. It also makes sense where conditions are dry, surfaces are dry, or the foam is going into deeper voids where a moisture-cure foam might cure unevenly. Another reason is stability, because Soudafoam 2K is designed for no post-expansion, which helps reduce the risk of frame distortion. The trade-off is working time, because once activated the can must be used promptly and emptied within five minutes.

Q) What is Soudafoam 2K most commonly used for on site?

A) Soudafoam 2K is most commonly used for installing and sealing door and window frames, filling gaps around openings, and cavity filling where a dense, strong foam is preferred. It is also used for general renovation and making good, such as closing voids around services, boxing-in areas, and sealing draught paths in static joints. Because it cures quickly and can be cut in around fifteen minutes, it suits work where you want to trim and move on without waiting for a slow cure. It also contributes to insulation and sound reduction, making it useful where comfort and air tightness matter as well as speed.

Q) Does Soudafoam 2K stick to brick, block, timber and metal?

A) Yes, Soudal Soudafoam 2K bonds well to most common building substrates, including brick, block, concrete, stone, plaster, timber and many metals. It generally provides strong primerless adhesion when surfaces are sound and clean. The usual limitations apply for polyurethane foams, so it is not suitable for low surface energy plastics such as PE, PP and PTFE, and bonding can be reduced on oily, dusty, wet or friable surfaces. For best results, clean back to a stable edge, remove loose material, and protect visible finishes nearby. If you are applying to an unusual surface or a critical detail, carry out a small compatibility test before committing to the full installation.

Q) Can Soudal Soudafoam 2K be used for door and window frame fitting without distorting the frame?

A) Soudafoam 2K is specifically suited to frame fitting because it is designed for no post-expansion, which helps reduce the risk of late movement that can push frames out of alignment. The key is controlled application and correct installation practice. Frames should be set, packed and fixed correctly before foaming, and you should apply the foam in a measured bead rather than overfilling. Fill to around one third of the gap depth and allow it to expand, instead of trying to fill the void fully in one pass. This supports uniform pressure and reduces squeeze. Once cured it forms a dense, stable fill that supports air sealing and insulation, while maintaining cleaner tolerances.

Q) How do you activate Soudal Soudafoam 2K and why does the five-minute rule matter

A) Activation is done at the can, releasing the second component and mixing it into the foam. Turn the black disc at the base five times to release the hardener, then shake the can around twenty times to mix thoroughly. After activation, the chemical reaction starts, which is why the product must be dispensed promptly and the can emptied within five minutes. If you do not use it quickly, the foam can begin curing within the can and the valve or applicator can block, creating waste and inconsistent output. The five-minute window also encourages job planning, so frames are prepared, access is clear, and joints are ready before activation, helping the foam perform as intended.

Q) What colour should the mixed foam be, and what if it looks inconsistent?

A) When Soudafoam 2K is activated and mixed correctly, the dispensed foam should be a uniform light green colour. That colour consistency is a practical indicator that the two components are properly mixed and the foam will cure predictably. If the foam looks streaky, patchy, or not consistently coloured, stop and re-check the activation and shaking process. Turn the black disc as specified and shake again thoroughly, then dispense a small amount onto waste material to confirm it is consistent before continuing into the joint. Applying poorly mixed foam can lead to uneven curing, variable density and weaker results, which is especially undesirable around frames where stability matters. Consistency at the start is the best way to protect finish quality.

Q) How much does Soudafoam 2K expand and how do you avoid overfilling gaps?

A) Soudafoam 2K expands significantly during curing, with controlled expansion of around 192%, so measured application is essential. A good rule is to fill a gap to about one third of its depth, then allow expansion to complete the fill. This helps reduce waste and limits outward pressure on frames and linings. For wider gaps, apply a controlled bead in stages rather than trying to fill everything in one pass, especially around delicate frame profiles. Keep the bead continuous for air sealing, but avoid heavy build-up at corners. Controlled filling also makes trimming easier and reduces clean-up. Because the foam has no post-expansion after curing, what you see once cured is more stable, but only if you apply it correctly.

Q) How quickly does Soudal Soudafoam 2K cure, and when can it be trimmed?

A) Soudafoam 2K is designed for rapid workflow. Under typical conditions it forms a skin in around nine minutes and can often be cut after around fifteen minutes, which helps you trim and progress quickly. Full load-bearing capacity takes longer, with guidance indicating around four hours for a thirty millimetre bead to become fully loadable. Temperature and bead thickness still influence cure times, even though the foam does not rely on external moisture. Thicker sections take longer to develop strength through their depth, so avoid sealing over or mechanically stressing the foam too soon. For frame fitting, this faster handling reduces downtime, but correct packing and fixing should still be in place as normal.

Q) Does Soudafoam 2K provide good insulation and help reduce draughts?

A) Yes, Soudafoam 2K provides a dense fill that helps close air leakage paths around frames, penetrations and voids, which can significantly reduce draughts. It also offers strong thermal insulation performance, with a thermal conductivity of around 0.034W/m.K, helping reduce cold bridging at common weak points in the building envelope. In practical terms, sealing perimeter gaps properly can improve comfort and reduce local cold spots that can contribute to condensation risk. The best results come from continuous, well-controlled application, because small missed sections can still leak air. Once cured, trim neatly and cover the foam where required as part of the final detail. Protection also improves durability and keeps the finish tidy.

Q) How effective is Soudafoam 2K for acoustic sealing and noise reduction?

A) Soudafoam 2K can contribute strongly to acoustic performance by sealing gaps that would otherwise allow airborne noise to pass. Sound insulation performance is quoted at around 63dB, which highlights its potential value in reducing sound leakage through openings and junctions. It is useful around frames, service routes and voids where small gaps can undermine otherwise solid constructions. The overall acoustic outcome still depends on the full build-up, because sound can travel through flanking paths and unsealed junctions elsewhere. To get the most from the foam, focus on continuity, avoid voids within the joint, and complete the sealing line around the perimeter. Trim cleanly once cured and apply the final finishes so the seal remains continuous and protected.

Q) Can Soudafoam 2K be painted, plastered over or covered after curing?

A) Once cured, Soudafoam 2K can be trimmed and then covered with suitable finishes such as plaster, paint, boards or sealants, depending on the detail. This is important because polyurethane foams are not UV-resistant, so exposed foam should be protected from sunlight. For best results, allow the foam to cure sufficiently before finishing, because cutting time is not the same as full cure through thicker sections. Ensure the surface is clean and stable, and choose a finish that suits the application. Around frames, a compatible sealant and trim detail can help protect the foam and improve appearance. In refurbishment work, covering the foam also reduces the risk of accidental damage and maintains long-term seal integrity.

Q) What are the main limitations of Soudal Soudafoam 2K?

A) The biggest limitation is working time. Once activated, Soudafoam 2K must be dispensed promptly and the can emptied within five minutes, so it is not suitable for slow, stop-start jobs. It is also not suitable for PE, PP and PTFE, and it should not be applied to dusty, oily or unstable surfaces where adhesion will be compromised. Like most PU foams, it is not UV-resistant and needs protection if exposed. It is intended for static joints and controlled filling, not for movement joints that require elastic sealants. It should not be used as a stand-alone solution where fire stopping compliance is required unless the specific detail is covered by the appropriate tested and specified system.

Q) What is the best way to prepare a frame or opening before using Soudafoam 2K?

A) Preparation is mainly about readiness and cleanliness, because once Soudafoam 2K is activated you have limited time. Dry-fit the frame or component, confirm alignment, install packers, and complete mechanical fixing where required before you activate the can. Clean the joint faces so they are free from dust, loose mortar, grease and friable material, and protect visible finishes with tape where needed. Ensure access is clear around the full perimeter so you can maintain a continuous bead without rushing. Have trimming tools and cleaning materials ready before you start. This planning reduces waste, improves bead control, and helps avoid overfilling in corners and tight spots. Proper preparation is one of the simplest ways to achieve a cleaner finish and fewer call-backs.

Q) How do you apply Soudafoam 2K neatly into gaps and voids?

A) Apply Soudafoam 2K in a controlled bead, keeping the can and valve oriented correctly for consistent output. Dispense into the joint steadily and fill only around one third of the gap depth, allowing expansion to complete the fill. Work methodically around frames and apply in stages on larger gaps to reduce pressure and minimise squeeze-out. Keep the bead continuous for air sealing, but avoid excessive build-up at corners. Because the foam cures quickly, avoid stopping mid-run where possible. If you need to make good a larger cavity, plan the route so you can empty the can within the five-minute window. Once cured, trim flush with a sharp blade and proceed with the finishing detail to protect the foam.

Q) How much coverage can I expect from a can of Soudafoam 2K?

A) Coverage depends on joint width, depth, and how controlled your bead is, but test guidance gives a useful benchmark. A 400ml can is quoted at roughly 10L box yield and around 8m joint yield under EN 17333-1 testing, which assumes standardised conditions and joint geometry. In real use, deeper voids and wider gaps reduce linear metres, while narrow, well-controlled gaps increase it. Because it expands by around 192%, you should not fill the joint fully at the application stage, which helps efficiency and reduces waste. For ordering, base estimates on the size and length of joints and allow a margin for irregular gaps and trimming waste.

Q) How do you clean up Soudafoam 2K if it gets on tools or surrounding surfaces?

A) Clean-up is easiest while the foam is still uncured. Wipe away fresh foam immediately and use a suitable PU foam cleaner on tools and many non-porous surfaces, testing first on sensitive plastics, coatings and painted finishes. Protecting surfaces before application is always better than relying on cleaning afterwards. Once the foam has cured, it can only be removed mechanically by trimming and scraping, so accidental smears on finished surfaces can be difficult to correct without damage. Where assistance is needed for cured residue, a cured PU foam remover can help release it, but compatibility testing is still important. Keeping cleaning materials on hand before activation helps you react quickly, which is especially useful given the fast cure profile.

Q) What safety precautions should be followed when using Soudal Soudafoam 2K?

A) Treat Soudafoam 2K as a pressurised aerosol and a reactive polyurethane product. Use it in well-ventilated areas, avoid breathing vapours or mist, and wear gloves and eye protection as a minimum. Keep it away from heat, sparks and open flames, and do not smoke during use. Plan access so you are not applying overhead without protection, and protect surrounding finishes to reduce the need for aggressive cleaning. Avoid skin and eye contact with uncured foam, and wash promptly with plenty of water if contamination occurs. Store the can upright and protect it from high temperatures and direct sunlight. Never burn cured foam. Trim and remove cured foam mechanically, then cover it as part of the final detail.

Q) What are the most common mistakes with Soudafoam 2K, and how do you avoid them?

A) The most common mistake is activating the can before the job is ready, then running out of time and wasting product because the can must be emptied within five minutes. Another is under-shaking, which can lead to inconsistent mixing and unreliable curing, so follow the activation and shaking routine and check for uniform light green foam. Overfilling is also common, especially around frames, so fill to around one third of the gap and allow expansion to complete the seal. Poor surface preparation can reduce adhesion, so clean back to stable substrates and remove dust and loose material. Finally, leaving foam exposed to sunlight leads to degradation, so protect cured foam with a suitable finish for durability and appearance.

Technical Data Sheet

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