What Is Permanent Formwork? Types, Benefits and Applications

Murs Projects
Feb 19
6 min read

Modern construction is evolving quickly, and one of the most important shifts in how we build walls and other structures involves the concept of permanent formwork. Unlike traditional timber or steel forms, which are removed after the concrete cures, permanent formwork remains in place. This method not only simplifies the build process but also contributes to greater sustainability and long-term performance.

In this guide, we explore what permanent formwork is, how it differs from temporary formwork, the benefits and drawbacks of using it, and the different types of systems available. Whether you're a builder, project manager, architect, or curious property owner, this article will help you understand the potential of permanent formwork in the construction landscape.

What is Permanent Formwork?

Permanent formwork consists of pre-manufactured panels or blocks that are assembled on site and remain in place after the concrete is poured. These formwork elements create a cavity that is subsequently filled with concrete and steel reinforcement. Once the concrete cures, the panels continue to act as a permanent part of the wall or structural element.

By comparison, temporary formwork, such as timber or reusable steel forms, must be stripped after the concrete has set, creating additional labour and waste. In permanent systems, the form stays in place, providing additional stability and often contributing to fire, acoustic, and thermal performance.

One widely used example in Australia is AFS Wall Installation in Australia, known for its speed of assembly and structural reliability.

Permanent vs Temporary Formwork

The main distinction between permanent and temporary formwork lies in their lifecycle and purpose. Temporary formwork is designed to be removed and reused; builders erect the forms, pour the concrete, and then strip the forms off once the concrete is strong enough to support itself. This method can be labour-intensive and generates waste.

On the other hand, permanent formwork is designed to stay in place. It typically consists of lightweight panels or blocks made from materials like PVC/polymer, fibre cement, or insulating foam. These panels click or lock together, creating a mould that is filled with concrete and reinforcing steel. When the concrete cures, the panels remain as part of the finished wall, often providing additional structural stability and protection against soil pressure or moisture.

Types of Permanent Formwork Systems

Not all permanent formwork is the same. Several systems and materials have been developed to address different project requirements, budgets, and performance goals. Below are some of the most common types of permanent formwork systems used today.

PVC/polymer-based systems: Often referred to as stay-in-place PVC formwork, these panels are lightweight and easy to assemble. They typically come with integrated channels or conduits for services. Products like Dincel or AFS Rediwall fall into this category. The PVC outer shells are designed to provide a waterproof barrier and allow for faster construction.

Fibre-cement or fibre-reinforced systems: These systems utilise panels made from fibre-cement boards or other fibre-reinforced materials. They offer greater rigidity and often a more traditional surface for finishing. Examples include Ritek XL Wall and systems sold by companies such as Trustruct. Fibre-cement systems generally have higher fire and acoustic ratings and can be skim-coated, rendered, or painted directly without needing additional cladding.
Insulated Concrete Forms (ICF): ICFs use expanded polystyrene (EPS) blocks or panels that snap together like Lego to form a cavity that is filled with concrete. The EPS remains in place and provides continuous insulation on both sides of the concrete core. This system improves thermal performance and can reduce heating and cooling costs in the completed building. Zego’s ICF and Eco Block are examples used in Australia.
Hybrid systems: Some systems combine elements of polymer and fibre-cement or incorporate additional features such as built-in insulation layers, acoustic damping, or unique surface treatments. They are designed to address specific project needs, such as high fire resistance, improved energy efficiency, or simplified finishing.

Benefits of Permanent Formwork

Permanent formwork has rapidly gained popularity thanks to a range of benefits that appeal to builders, developers, and property owners alike. Below are some of the most compelling advantages.

Faster construction: Erecting lightweight panels is quicker than building a brick or block wall. Once the formwork is assembled, concrete is poured in a single operation.

Reduced labour costs: Permanent formwork eliminates the need for trades like bricklaying on many projects and reduces the number of labourers required on site.

Greater safety: With fewer heavy lifts and repetitive tasks, construction sites are generally safer and less cluttered. The formwork itself often provides early structural stability, reducing the risk of form collapse.
Enhanced structural stability: Unlike temporary forms, which are removed after curing, permanent panels stay in place and continue to reinforce the structure. They can act as a composite system with the concrete, improving load-bearing capacity and resistance to soil pressure.

Improved waterproofing and protection: PVC and other polymer panels offer a built-in moisture barrier, protecting concrete from soil and water ingress. This feature can be especially important in basements and retaining walls.

Better thermal and acoustic performance: ICF systems provide continuous insulation, reducing heat loss and improving comfort. Fibre-cement systems and some polymer products also offer high acoustic ratings, making them suitable for noise-sensitive applications.
Sustainability: Permanent formwork reduces site waste since the panels remain part of the building. Systems often require less steel reinforcement and concrete compared with conventional construction, lowering the embodied carbon of the structure. Moreover, some materials can be recycled or reprocessed at the end of the building’s life.

Drawbacks and Considerations

Like any construction method, permanent formwork comes with its own set of challenges. Understanding these issues will help you determine whether the system is appropriate for your project and how to mitigate potential problems.

Waterproofing challenges: PVC-based systems may not be inherently waterproof if installed incorrectly. While manufacturers supply membranes and joints to ensure water tightness, poorly sealed systems can allow water ingress, particularly in basements or retaining walls.

Bracing and support: Even though manufacturers advertise minimal bracing, the reality is that corners, intersections, doors, and windows often require extra prop support during the pour. This can add complexity and time to installation.

Sizing and modular constraints: Panels come in set widths and heights. In projects with complex geometries, builders may need to add joiners or create custom infill pieces, which can slow down the job.

Finishing surfaces: PVC and polymer surfaces sometimes require special primers or adhesives for renders and cladding. Traditional cement-based renders may not bond properly, so builders need to select acrylic-based or mechanically fixed finishes. Fibre-cement panels offer a more familiar surface, but still require proper detailing.

Cost considerations: Although labour savings can offset material costs, permanent formwork systems often have higher up-front costs than conventional blockwork. Projects with small wall areas or simple forms may not realise a substantial cost benefit.

Applications and Suitability

Permanent formwork is versatile and can be used in a variety of building types and applications. Here are common areas where it provides significant advantages:

Basements and below-grade structures: The built-in moisture barrier of polymer panels protects concrete from soil and water ingress, making these systems ideal for basements and retaining walls.

Residential homes: Many builders use permanent formwork in single dwellings or multifamily housing. The reduction in labour and speed of construction can help meet tight project timelines. For example, some builders report nearly eliminating the need for bricklayers.

Commercial and multi-residential projects: In mid- to high-rise buildings, permanent formwork reduces scaffolding requirements and speeds up core and wall construction. Its ability to incorporate services within the formwork is appealing to developers and architects.

Infrastructure: Permanent formwork can be used for retaining walls, lift shafts, stair cores, bridge abutments and other infrastructure projects where durability and speed are important. The performance of these systems ultimately depends on the Structural walls types selected - each offering different load-bearing capacities, acoustic ratings, and suitability for above- or below-grade conditions.

Green and sustainable buildings: Because these systems often incorporate insulation and reduce overall material usage, they are well-suited for projects pursuing green building certification or simply aiming to lower their environmental impact.

Conclusion

Permanent formwork is an innovative and increasingly popular method of constructing walls and other structural elements. It offers speed, safety, sustainability, and improved performance compared to traditional formwork systems. While there are considerations such as waterproofing, bracing, and sizing that require attention, the overall benefits often outweigh the drawbacks. For builders and developers looking to accelerate their projects while maintaining high standards of quality and efficiency, permanent formwork is a technology worth considering.

If you’re interested in learning more about how permanent formwork could work for your next project, whether it’s a basement, retaining wall, custom home, or multi-residential development, speak to the experts at Murs Projects. Our team specialises in installing a variety of permanent formwork systems and can provide advice on the best solution for your needs.