Written by Silverleaf Roofing | Published June 2025
Anticon and Foilboard are the two most common roof insulation products used under metal roofing in the Penrith and Western Sydney area. Anticon is a foil-backed blanket typically used during new roof installation, while Foilboard is a rigid foam board installed on top of existing ceilings or under rafters.
Both options reduce heat transfer, but they perform differently depending on your roof type, budget, and whether you are building new or upgrading an existing home. This article breaks down the key differences so you can choose the right product for your property in Penrith, the Blue Mountains, or the Hawkesbury.
Understand what Anticon and Foilboard actually are
Anticon is a flexible insulation blanket. It is a layer of glasswool or polyester wadding bonded to a reflective foil facing. It is rolled out under metal roofing sheets as they are installed, sitting between the purlin and the roof sheet.
Foilboard is a rigid expanded polystyrene (EPS) panel with reflective foil laminated to one or both sides. It comes in sheets and can be cut to fit. It is installed above the ceiling joists, in rafter spaces, or directly under roof cladding depending on the application.
Both products use reflective foil to reject radiant heat, which is a major heat transfer pathway in Australian summers. The insulation core in each product then handles conductive heat, slowing the transfer of heat through your roof structure.
Silverleaf Roofing works with both products on new builds and reroofing projects across Western Sydney and the Hawkesbury region, so we have practical experience with how each performs in local conditions.
Compare Anticon and Foilboard side by side
The table below summarises the key differences between the two products to help you quickly identify which suits your situation.
| Feature | Anticon Blanket | Foilboard Rigid Panel |
|---|---|---|
| Form factor | Flexible roll blanket | Rigid EPS sheet |
| Typical thickness | 40mm to 100mm | 25mm to 100mm |
| R-value range (total system) | R1.3 to R2.5 | R1.0 to R3.0+ |
| Best install stage | During new roof or reroof | New build or retrofit |
| Suitable roof types | Metal roofing (Colorbond, Zincalume) | Metal, tile, flat roofs |
| Condensation resistance | Good (acts as a drainage layer) | Good when correctly detailed |
| DIY friendly | No (requires roof removal) | Possible in accessible spaces |
| Typical supply cost per m2 | $6 to $14 | $8 to $22 |
R-values shown are indicative. Your actual system R-value depends on thickness, air gaps, installation quality, and whether a ceiling insulation layer is also present. The NCC (National Construction Code) sets minimum R-value requirements for your climate zone.
Understand the cost of each option for Western Sydney homes
Cost depends on roof size, product thickness, access difficulty, and whether you are doing a new install or a retrofit. The table below gives realistic installed cost estimates for a typical Penrith or Western Sydney home.
| Product | Roof size (m2) | Supply only (approx) | Installed cost (approx) |
|---|---|---|---|
| Anticon 65mm | 150m2 | $1,050 to $1,500 | $1,800 to $3,000 |
| Anticon 100mm | 150m2 | $1,500 to $2,100 | $2,400 to $3,800 |
| Foilboard 50mm | 150m2 | $1,500 to $2,500 | $2,800 to $4,500 |
| Foilboard 75mm | 150m2 | $2,200 to $3,300 | $3,500 to $5,500 |
Anticon is nearly always cheaper when installed during a reroof because labour is already on site and the roof is open. Adding Anticon to an existing roof means removing and reinstating the roof sheets, which adds significant cost.
Foilboard can sometimes be installed from inside the roof space without removing roof sheets, making it a more cost-effective retrofit option depending on your roof design and access.
Know which product suits your Penrith or Blue Mountains climate
Penrith and Western Sydney sit in NCC Climate Zone 6, which has hot summers and cool winters. The Blue Mountains and Hawkesbury areas span Zone 6 and the cooler Zone 7 in higher elevations. Both zones require roof insulation that manages summer heat gain AND winter heat loss.
Here is how each product performs in local conditions:
- Summer heat rejection: Both products use reflective foil facing. Anticon installed under metal roofing with a clear air gap performs well at reflecting radiant heat before it reaches your ceiling. Foilboard with dual foil faces offers strong performance in the same application.
- Winter warmth retention: Foilboard with higher R-values (75mm or 100mm) performs better in cooler climates like the Blue Mountains where winter temperatures regularly drop below 5 degrees Celsius.
- Condensation management: Penrith experiences warm, humid summer air that can cause condensation under metal roofing. Anticon is specifically designed to manage this, allowing moisture to drain away rather than drip onto your ceiling.
- Bushfire zones: Many properties in the Hawkesbury and Blue Mountains are in Bushfire Attack Level (BAL) zones. Check that your chosen insulation product is compliant with AS 3959 requirements for your BAL rating before purchase.
The Silverleaf Roofing team regularly installs insulation on properties across all of these zones and can advise on the right product thickness for your specific location and roof design.
Identify when to choose Anticon over Foilboard
Anticon is the right choice in these situations:
- You are having a new Colorbond or Zincalume roof installed and want insulation included in the same job.
- You are reroofing and the roof sheets are being removed anyway. Adding Anticon at this stage costs very little extra in labour.
- Your roof has limited ceiling space or rafter depth that makes rigid board installation difficult.
- You want a product specifically designed to handle condensation drip from metal roofing.
- Your budget is tighter and you want a proven, cost-effective option that meets NCC minimums.
Anticon is the most commonly specified insulation for residential metal roofing in Western Sydney for good reason. It is purpose-built for the application, easy to install during a roof job, and performs reliably in our climate.
Identify when Foilboard is the better option
Foilboard makes more sense in these situations:
- You want a higher total system R-value than Anticon can practically deliver under your roofing.
- You are retrofitting insulation to an existing roof without wanting to remove roof sheets.
- Your home has a flat or low-pitch roof where Anticon cannot be installed under sheets easily.
- You need insulation under a tile roof, where Anticon is not typically used.
- You are building a new home and want to combine Foilboard in the roof with bulk insulation in the ceiling for a high-performance thermal envelope.
- You are working on a commercial or shed application where rigid boards suit the construction method better.
Foilboard brands commonly available in the Penrith area include Kingspan Foilboard, CSR Bradford Anticon (note: Bradford also makes rigid foil products), and Rmax. Thickness options range from 25mm up to 100mm with varying R-values and fire ratings depending on the product line.
FAQs on Anticon vs Foilboard roof insulation
Can I add Anticon to my existing Colorbond roof without replacing the sheets?
Not easily. Anticon must be installed under the roof sheets, which means the sheets need to be removed and reinstated. For an existing roof, this is a significant cost. Foilboard or ceiling-level bulk insulation is usually a more practical retrofit option.
What R-value do I need for a Penrith home under the NCC?
Penrith is in NCC Climate Zone 6. The minimum total roof insulation R-value for Zone 6 is R3.2 for roofs (combined ceiling and roof insulation). Anticon alone typically does not meet this, so it is usually combined with ceiling batts to reach the required value.
Is Foilboard safe to use near downlights?
Standard EPS Foilboard must maintain clearance from downlights and heat-producing fixtures. Fire-rated Foilboard products are available for applications where fire resistance is required. Always check the product’s fire hazard properties and consult your builder or roofer before installing near heat sources.
Does Anticon prevent condensation under Colorbond roofing?
Yes. Anticon is specifically engineered for this purpose. The blanket layer acts as a thermal buffer that keeps the underside of the roof sheet warmer, reducing the likelihood of condensation forming. Any moisture that does form can drain along the blanket rather than dripping onto your ceiling.
How long does roof insulation last in Western Sydney conditions?
Quality Anticon and Foilboard products are rated to last the life of the roof when correctly installed, typically 25 to 40 years. UV exposure, physical damage, and moisture ingress from roof leaks are the main factors that degrade performance over time.
Can I use both Anticon and Foilboard together?
Yes, and this combination is used in high-performance builds. Anticon under the roof sheet handles condensation and adds reflective performance, while Foilboard in the rafter space or above the ceiling adds bulk R-value. This approach is common in cooler Blue Mountains properties where high R-values are needed.
Wrap up and next steps
Anticon is the practical first choice for new metal roofs and reroofing projects in Penrith and Western Sydney. Foilboard suits retrofit applications, tile roofs, and situations where a higher R-value is needed. Many high-performance homes use both together to meet NCC requirements and improve year-round comfort.
If you are planning a new roof, reroof, or want to improve your home’s insulation, Silverleaf Roofing can help you choose the right product and install it correctly. Call us on 0413 461 110 to discuss your roof and get a quote tailored to your home.