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When laying timber, engineered, or bamboo flooring, the right adhesive prevents call-backs for lifting, cupping, or squeaking. Bostik Ultraset SF provides a flexible, high-strength bond that moves with timber, ensuring a durable, quiet floor. This solvent-free adhesive is specifically formulated for lasting performance over concrete subfloors, even those with radiant heating.
Timber and bamboo flooring installations demand an adhesive that can adapt. Ultraset SF is a single-component polyurethane adhesive engineered to meet these specific challenges. Unlike traditional rigid or solvent-based adhesives, its solvent-free formulation means zero VOCs, protecting installers and occupants alike. Its inherent flexibility accommodates the natural movement of timber without compromising bond integrity, preventing common flooring failures by creating a durable, water-resistant connection that will not re-emulsify from residual moisture. This maintains floor stability and appearance over time.
Bostik Ultraset SF is designed for longevity and performance, with specific properties addressing critical flooring challenges. Its 600% elongation ensures the adhesive can absorb the natural expansion and contraction of timber and bamboo, preventing stress-induced cracking or delamination of the bond line. A Shore A hardness of approximately 52 provides a firm yet elastic bond, allowing sufficient movement without sacrificing structural adhesion. Meeting the BS EN 14293 standard for parquet adhesion with a tensile shear strength of 1.4 N/mm² means it delivers a reliable, tested bond strength for demanding flooring applications. As a solvent-free, zero VOC formulation, it contributes to healthier indoor air quality during and after installation, making it suitable for residential and commercial projects alike. This formulation also makes it non-flammable, enhancing site safety.
Bostik Ultraset SF comes ready to use, requiring no mixing, which streamlines application. It spreads as a smooth paste that holds peaks, allowing for precise trowel application. The adhesive offers a tack-free time of approximately 4 hours and light traffic walk-on in 8-10 hours at 23°C and 50% RH, providing a workable window while still allowing for efficient project progress. For clean-up, uncured adhesive can be removed using mineral spirits, Shellite, or paint thinners, or with Bostik Handy Wipes, taking care with prefinished timber coatings.
Bostik Ultraset SF excels in direct stick applications for a wide range of timber and bamboo flooring. It is the adhesive of choice for adhering parquet, solid strip softwood, hardwood, engineered, and bamboo flooring directly to concrete subfloors. Its flexible nature makes it particularly effective for installations over radiant heating systems, where thermal cycling demands an elastic bond that won't crack under stress. The adhesive also provides a secure, acoustic-enhancing bond for recommended acoustic underlays, integrating seamlessly into noise reduction systems for multi-story buildings or commercial spaces.
Successful timber flooring installations depend heavily on proper subfloor preparation. Ultraset SF is often the final bonding layer in a comprehensive subfloor system. For new or ground floor concrete slabs, especially where moisture is a concern, the process typically begins with Bostik Ultraseal Vapour Barrier to prevent moisture migration. If the subfloor requires levelling, Bostik UL-200 self-levelling compound is applied, often primed with Bostik PrimeGrip Non-Porous. Ultraset SF then forms the critical flexible bond to this prepared, stable, and dry subfloor, ensuring the long-term performance of the timber flooring.
Solvent-free formulations like Ultraset SF reduce airborne contaminants, contributing to healthier indoor air quality. This adhesive also has zero VOCs and is non-flammable, minimising site hazards during installation.
No, Ultraset SF should not be installed on wet surfaces. Concrete subfloors must be dry, with a Water Vapour Transmission Rate (WVTR) not exceeding 15g/m²/24 hours (calcium chloride method). For ground floor or new slabs, use Bostik Ultraseal Vapour Barrier to manage moisture before adhesive application.
Ultraset SF remains flexible after full cure with an elongation of 600%. This flexibility helps the adhesive accommodate natural movement and expansion/contraction of timber flooring, reducing the risk of bond failure or cupping, especially over radiant heating systems.
Yes, Bostik Ultraset SF is suitable for direct stick applications over concrete subfloors incorporating radiant heating. Its flexibility helps maintain bond integrity under temperature fluctuations.
| Application | Key benefit | Primary trades |
|---|---|---|
| Direct stick timber flooring to concrete subfloors | Meets EN 14293:2006 for parquet adhesion and ASTM C794 for peel adhesion to Australian hardwoods, ensuring a secure, lasting bond. | Flooring installers, builders, renovators |
| Bonding acoustic underlays as an intermediate layer | Provides excellent acoustic properties, contributing to sound insulation requirements within the flooring system. | Flooring installers, acoustic consultants |
| Timber flooring over radiant heating systems | Maintains flexibility (600% elongation) and bond integrity under temperature fluctuations associated with heated subfloors. | Flooring installers, builders |
| Adhering bamboo flooring to concrete subfloors | Forms a strong, flexible bond that accommodates bamboo's sensitivity to moisture effects, especially when used with a vapour barrier. | Flooring installers |
Signal word: Danger
Wear protective gloves, safety glasses or goggles, and protective clothing. If ventilation is inadequate or emissions occur, wear suitable respiratory protection.
Ensure adequate ventilation during use. Provide extract ventilation to points where emissions occur.
Store in original sealed containers, under cover, in dry conditions, between 5°C and 30°C. Keep containers tightly closed and locked up, out of reach of children. This product is a Schedule 6 poison and must be stored, maintained, and used in accordance with relevant regulations. Dispose of waste and contaminated packaging in accordance with local environmental regulations.
Proper substrate preparation is critical for bond integrity and preventing floor system failures, ensuring the adhesive performs as specified.
Surface prep: Ensure surfaces are clean, dry, and free of voids, curing compounds, loose materials, oil, or grease. Subfloors must be flat to 3mm over 3m and structurally sound. For uneven areas, use Bostik UL-200 levelling compound. Concrete slabs should conform to AS2870 standards.
Primer: Optional. For moisture management, apply Bostik Ultraseal Vapour Barrier to ground floor slabs and new green slabs. Ensure WVTR does not exceed 15g/m²/24 hours before flooring. If levelling with Bostik UL-200 over a vapour barrier, use Bostik PrimeGrip Non-Porous primer.
Surface prep: Dense burnished concrete surfaces must be abraded or sanded back to achieve a mechanical key. Consult a Bostik Technical Representative for specific guidance.
Primer: Not required after proper mechanical preparation, unless moisture or levelling issues are present as above.
| Property | Value |
|---|---|
| Colour | Brown |
| Viscosity | Smooth paste; holds peaks |
| Composition | Polyurethane |
| Application Temperature | 5 to 30°C |
| Specific Gravity | 1.31 Approx. |
| Cure Rate | 1.5-2.5 mm / 24hrs |
| Full Cure (1mm film) | Approx. 24 hrs |
| Elongation | 600% |
| Walk On Time | 8-10 hrs (light traffic) |
| Tack Free Time | Approx. 4 hrs @ 23°C 50% RH |
| Shore A Hardness | Approx. 52 |
| Tensile Strength In Shear (Timber to Timber, 2mm, BS EN 14293) | 1.4 N/mm² |
| VOC | 0 g/L |
| Water Solubility | Insoluble in water |
| Shelf Life | 12 months |
Here are some common examples on where Bostik Ultraset® SF Polyurethane Flooring Adhesive used by our customers.
