Description
StyroTherm XPS 50mm Slab Insulation — Standard Residential Compliance Benchmark
StyroTherm XPS 50mm is the standard benchmark for domestic under-slab construction projects. It is engineered specifically to help builders meet modern, strict home energy ratings effortlessly. Consequently, this premium rigid foam board delivers a powerful R1.55 thermal rating across its entire surface. It is the most popular choice in Melbourne for new residential raft slab configurations. Therefore, it is highly recommended by energy assessors for regular continuous underslab insulation blankets.
The Ultimate Shield for Hydronic Heating Systems
This 50mm slab insulation board provides an exceptional compressive strength rating up to 350kPa. Traditional glasswool or open-cell options lose their thermal effectiveness completely when exposed to sub-floor wetness. In contrast, this extruded polystyrene board is 100% water resistant and retains its shape permanently. This absolute moisture lock makes the 50mm profile vital for hydronic underfloor heating installations. Specifically, it directs all generated heat upward into the living spaces instead of letting it escape into the cold ground. Furthermore, it creates a highly comfortable, stable climate inside the home all year round.
Key Structural Applications for 50mm XPS Foam:
- Standard House Raft Slabs: Forms a continuous high-performance thermal blanket beneath domestic concrete.
- Hydronic Screed Heating: Minimizes operational energy costs by preventing downward heat loss.
- Commercial Footings: Provides reliable thermal isolation around secondary load-bearing structural joints.
Certified Performance and NCC Alignment
This Australian-made 50mm rigid insulation board features a fully sustainable design layout. For instance, it is completely free from eco-harmful manufacturing blowing agents like CFCs or HCFCs. Additionally, the lightweight boards are easy to cut and position on site without special tools. The product complies flawlessly with the rigid standards found in the National Construction Code (NCC). In short, the 50mm board offers the perfect balance of cost, strength, and thermal efficiency.
See our full slab insulation range in our online store.
📞 Call us on 03 8339 7111 to confirm stock or ask about lead timesPickup location: 56 Yellowbox Drive, Craigieburn VIC
🕒 Business hours: Mon–Thurs 6:30am–4:00pm | Fri 6:30am–3:00pm
🚚 Delivery is also available across Melbourne during business hours








