External Render on SIPs:
EPS is specifically designed to be rendered, but only as part of a certified ETICS system (External Thermal Insulation Composite System).
You never apply a traditional sand‑cement render directly onto EPS. Instead, you use a thin‑coat render system engineered for EPS.
The correct render build‑up on EPS:
1. EPS board (usually EPS70 or EPS100 façade grade)
2. Basecoat adhesive (polymer‑modified)
3. Full‑surface embedded alkali‑resistant mesh
4. Second pass of basecoat
5. Primer
6. Thin‑coat finish (silicone, silicate, or acrylic — silicone‑silicate is the sweet spot for Irish climate)
Kilsaran / Baumit / Weber
Mechanical Fixings (Insulation Anchors / TermoDübel)
These are essential in Ireland due to wind load and certification requirements.
Typical fixing pattern:
• 6 fixings per m² (standard)
• 8–10 fixings per m² in high‑exposure zones (west coast, gables, >10m height)
• Fixings must penetrate ≥ 40mm into solid substrate.
Types of fixings:
• Plastic hammer‑in anchors (most common)
• Screw‑in anchors (better for uneven substrates)
• Countersunk anchors with EPS caps (reduces cold bridging and avoids “ghosting”)
Fixing positions:
• At board corners (to prevent rocking)
• At board centres
• Staggered to avoid continuous vertical joints
