SPAX warm roof screws are engineered for fixing through compressible insulation into rafters. A flat countersunk head sits flush, while the under‑head fixing thread helps prevent head pop‑through so the waterproofing layer remains intact. The T‑STAR Plus (T30) recess gives positive drive control and the 4CUT point reduces starting torque and splitting. WIROX surface treatment improves corrosion resistance for exposed roof‑level work in multi‑layer build‑ups.