edge sealing when taping EPS boards: 7 Pro Tips
Complete Guide to Edge Sealing When Taping EPS Boards
For over 15 years, Simple Solutions 4 U has specialised in rendering and External Wall Insulation (EWI) systems, providing top-quality EPS boards, renders, and sundries at competitive prices. Our expertise ensures your building projects achieve maximum thermal efficiency and durability, and our step-by-step methodology aligns with industry best practices for installing EPS insulation foam board.
Why Proper Sealing Matters
Effective edge sealing when taping EPS boards is critical to prevent thermal bridging, moisture ingress, and air leaks. A continuous airtight barrier improves energy efficiency, reduces heating and cooling costs, and maintains indoor comfort. Learn more about preventing gaps in insulation boards in our professional guide to preventing gaps in insulation boards.
Understanding EPS Boards
Expanded Polystyrene (EPS) boards are lightweight, cost-effective insulation panels known for their high R-value per inch and moisture resistance. They offer excellent compressive strength and long-term performance when edges are properly sealed. For detailed cutting and fixing techniques, refer to the comprehensive EPS installation guide.
Choosing the Right Tape and Sealants
- Airtight Sheathing Tape: Use high-quality foil-faced or UV-resistant masking tape such as Blue Dolphin exterior TarpStucco UV-resistant tape to seal joints and edges.
- PU Foam Sealant: For irregular gaps and corners, apply a bead of polyurethane foam sealant using a Toughmaster foam applicator gun, then compress boards to seal voids. Follow the Ceresit mortar application tutorial for optimal adhesive placement.
- Specialised EWI Foam Tape: Expanding foam tape bridges uneven surfaces and maintains pressure against verge trims and reveals during installation.
Preparation Steps
- Clean and dry all EPS board edges and the wall substrate to remove dust and debris. See the Ceresit PU adhesive installation guide for substrate preparation techniques.
- Prime absorbent or non-absorbent substrates with a compatible primer such as Ceresit CT-16 primer to enhance tape adhesion and sealing performance.
- Lay out EPS boards in a brickwork pattern to stagger joints and minimise thermal bridging, ensuring a continuous insulation layer.
Application Techniques
Follow these steps for professional-grade edge sealing when taping EPS boards, incorporating guidelines from the Ceresit PU adhesive installation guide:
- Apply PU foam adhesive strips 2 cm from each edge and one central strip, then press the board to the wall and adjust within 20 minutes for perfect alignment.
- After mechanical fixing, seal all seams and board-to-board joints with foil-faced sheathing tape, smoothing with a roller or block to eliminate air pockets.
- Use expanding foam tape in reveals and around window and door frames, trimming excess foam once cured.
- Inspect sealed joints for gaps; fill minor voids with PU foam sealant and re-tape if necessary to maintain continuity.
Mechanical Fixings and Dowel Placement
Secure EPS boards with dowels featuring 6 cm flanges, spaced at least four per square metre. Drill holes, clear dust, and fix anchors two hours after foam adhesive application. Use universal insulation panel fixings for reliable anchorage, then cover anchor heads with EPS caps for a flush finish before rendering.
Reinforcement and Render Application
Once EPS boards are fully sealed and fixed, apply a reinforcing coat with alkali-resistant mesh. After embedment and curing, finish with your choice of through-coloured render. Enhance durability with CT-85 flexible adhesive and reinforcing mortar for superior crack resistance and bond strength.
Maintenance and Trade Discounts
Regular inspection of sealed joints and render integrity extends the lifespan of your EWI system. Simple Solutions 4 U offers ongoing property maintenance and structural repair services, including patch repair and colour matching, with exclusive discounts for trade customers.
Contact Simple Solutions 4 U
For expert advice on edge sealing when taping EPS boards and professional plastering and rendering services, call us at 07877 329 472 or email us. Alternatively, contact us online.
edge sealing when taping EPS boards FAQs
- How long does PU foam sealant take to cure? Typically tack-free in 10 minutes and fully cured within 30 minutes before trimming and taping.
- Can I paint over sheathing tape? Yes—once protected by render, sealed joints will blend seamlessly into the finished facade.
- Is edge sealing during winter installation effective? Use low-temperature rated adhesives and tapes such as Ceresit CT-240 Winter Additive for reliable sealing in cold conditions.
Implementing these practices for edge sealing when taping EPS boards guarantees an airtight, energy-efficient building envelope that stands the test of time.
