Ceresit CT84 Adhesive Foam 850ml UK — Express PU Bond for EPS & XPS

Achieving rapid, secure EPS board adhesion without the weight and extended curing time of traditional cement is precisely what the ceresit ct84 adhesive foam 850ml UK delivers for modern EWI systems. Designed specifically for professional installers, this high-yield polyurethane foam adhesive UK eliminates the need for mixing stations and water on site. It forms an integral part of our EPS adhesives & basecoats range, ensuring a flawless, fast-curing foundation for thin-coat render finishes.

As a premium system companion, it pairs perfectly with high-performance EPS insulation boards to create a highly efficient, thermally broken facade. Compared to heavy cementitious options, choosing this advanced foam adhesive UK significantly accelerates project timelines, allowing for mechanical fixing to commence in just two hours.

Key Benefits

• Blistering Installation Speed: Allows for mechanical pinning (dowelling) and basecoat application just two hours after fixing the boards, drastically reducing scaffolding time.
• Exceptional Coverage Yield: A single 850ml canister bonds up to 10m² of insulation—equivalent to a heavy 25kg bag of traditional cement powder—slashing transport and handling effort.
• Winter-Ready Curing Resilience: Your project stays on schedule through the coldest months — the advanced formula cures reliably even when overnight temperatures drop to -10°C after application at 0°C, so every board bond holds firm from day one.
• Elimination of Thermal Bridges: Your entire wall stays evenly insulated because the foam bonds at the same thermal performance as the EPS boards themselves (just 0.040 W/mK), eliminating the cold spots that traditional cement dabs create at every fixing point.
• Clean and Waterless Application: Ready to use straight from the gun without electricity, water, or mixing paddles, keeping the site exceptionally clean and hazard-free.

Technical Specifications

Parameter	Value
Volume	850 ml
Coverage Yield	Up to 10 m² per canister
Application Temperature	0°C to +40°C
Curing Resilience Limit	Down to -10°C
Time to Mechanical Fixing	Approx. 2 hours
Thermal Conductivity (λ)	0.040 W/mK

Application & Compatibility

Formulated for broad substrate compatibility, this PU adhesive provides formidable grip on mineral backgrounds without the need for intensive priming. It is a critical component for both new-build EWI installations and retrofit "render on render" upgrades, particularly when adhering graphite and white EPS boards to complex exterior facades.

• Bonds flawlessly to concrete, ceramic blocks, brickwork, existing render, and timber structures.
• Ideal for securing hard extruded polystyrene (XPS) in damp-prone DPC and plinth zones.
• Functions perfectly as a high-grade thermal gap-filler between installed insulation boards.

Installation Notes

For the cleanest result and maximum bond strength, apply the foam adhesive using a professional applicator gun in a continuous perimeter ribbon around the board's edge, combined with a distinct W-shape across the centre, instead of applying it as isolated dots.

Trade Insight

Using CT84 transforms logistics and ergonomics on the scaffolding. Eliminating the need to haul heavy 25kg bags of cement adhesive up multiple lifts saves immense physical strain on the crew. Because it tolerates curing temperatures down to -10°C, autumn and winter programmes run without interruption regardless of overnight temperature drops, and the lack of reliance on a site water supply removes a common logistical headache.

Is This Product Right For Your Project?

• Choose this product if: You need rapid, clean EPS/XPS bonding with fast curing times to accelerate your EWI installation schedule, particularly in cooler seasonal weather.
• Working with Mineral Wool? For breathable rock mineral systems, our dedicated mineral wool adhesives from the adhesive and basecoat collection provide the high vapour permeability these boards require — giving you the same fast, confident installation with the right formulation for the job.
• Addressing deep substrate deviations? For walls with substrate deviations beyond 20 mm, a traditional wet basecoat applied with a notched trowel provides the levelling depth your project needs. You can learn more about choosing between these methods in our dedicated guide on foam adhesive vs traditional UK options.

FAQ

How much insulation can I cover with one canister of Ceresit CT84?

A single 850ml canister typically covers up to 10m² of insulation (roughly 20 standard EPS boards), which significantly reduces both material and transport costs per square metre.

How soon after application can I mechanically fix the boards?

The fast-curing formula allows for mechanical dowelling to commence just two hours after the boards are pressed into place, drastically accelerating the installation process compared to cement adhesives.

Is this foam suitable for filling gaps between EPS boards?

Yes, the adhesive doubles as an excellent thermal gap filler, actively eliminating cold bridging between adjacent insulation panels to ensure a continuous and highly efficient thermal envelope.

Can I use this adhesive in wet or freezing conditions?

Application should take place in dry conditions from 0°C upwards. However, once applied, the adhesive is highly resilient and will continue to cure effectively even if ambient temperatures subsequently drop to -10°C overnight.

How should I dispose of spent CT84 canisters?

Spent canisters are classified as pressurised metal waste — your site waste carrier collects them separately for licensed recycling. Choosing CT84 over cementitious bags also reduces transport weight by up to 90% per square metre covered, which lowers the delivery carbon footprint for every project.

How do I ensure full system warranty coverage when using CT84?

Following the manufacturer's continuous perimeter ribbon pattern — a bead around the board edge plus a central W-shape — ensures every board sits firmly and maintains consistent thermal contact across the full facade. This bead pattern takes just a few seconds per board and delivers the secure, weatherproof bond that keeps your EWI system warranty fully valid for its entire service life. The Installation Notes section above illustrates the correct technique, and your Ceresit system certificate confirms the approved application method for Building Control documentation.