What is ICF construction?

ICF construction, also known as Insulated Concrete Form construction, is a modern building method that combines the strength and durability of concrete with the energy efficiency of insulation. It involves the use of interlocking hollow forms, typically made of expanded polystyrene (EPS) or other insulating materials, which are stacked and filled with concrete to create the walls of a structure.

How does ICF work?

The process of ICF construction typically involves the following steps:

1. Formwork Assembly: The interlocking ICF forms are assembled on-site to create the desired wall shape and size. These forms consist of two panels that are connected with plastic or metal webs, creating a cavity in between.

2. Reinforcement Placement: Steel reinforcement, such as rebar, is placed within the cavity of the ICF forms to provide additional strength to the structure.

3. Concrete Pouring: Once the forms and reinforcement are in place, concrete is poured into the cavity. The concrete fills the entire space, encapsulating the insulation and forming a solid, monolithic wall.

4. Curing and Finishing: The concrete is left to cure and gain strength. Afterward, interior and exterior finishes can be applied to the walls, such as drywall, stucco, siding, or brick, depending on the desired aesthetics.

ICF Cost

Because of reduced relative operating expenses, ICF property ownership costs are always lower over time than traditional construction. During their extended lifespan, ICF structures require far less upkeep.

To complement the structural energy efficiency, owners typically install energy-efficient water heaters and windows, among other things, cutting energy expenses even further. In addition, a 1 Euro reduction in operating costs of ICF homes can improve the value of a normal home by 20 Euro. So, if you save an average of Euro 250 a month on energy, your house is worth about Euro 50,000 more than comparable traditional built homes.

How Long Does ICF Construction Take?

It depends on a range of factors including the size and complexity of the building. As an example, Rapidform would expect to complete a typical  two-story semi-detached block of houses in 10 working days from floor to wall plate. 

What Are the Pros and Cons of ICF Construction?

The Major advantages of ICF constructions include:

Construction Speed

The ICF building technology is lightweight and user-friendly. It does not require as much labour as older building methods. This saves critical time compared to traditional building methods because they can be put together quickly and are less affected by inclement or harsh weather than block or timber construction.


One of the most significant advantages of the ICF construction system is the airtightness it ensures. Because the insulation in an ICF structure is continuous, there is no way for outside air to get into the residence. This increases the BER rating of the building.

Savings on Energy Bills

ICF homes are extremely energy efficient and can easily get an ‘A’ BER Grade. Because of this efficiency level, less energy is required to heat the home, lowering the energy bill in the long and short term.

Fire Resistance

In the event of a fire, ICFs provide passive fire protection by slowing the spread of flames.

Wind Resistance

Steel-reinforced concrete ICF wall systems contribute to a continuous load path. The walkway holds the building together during high winds by transferring the stress from the roof to the ground.

Construction Safety

Due to the lightweight nature of parts, the risk when manually handling ICF is much smaller than when building blocks or timber frame houses. Also, as less labour is required onsite there is inherently less risk than with older building methods as there are simply fewer people. ICF construction does not require cranes which decreases the likelihood of an incident.


The concrete and steel reinforcing in the walls make ICF structures extremely structurally sound. ICF structures are called ‘disaster-proof,’ having withstood the harshest weather, including hurricanes.

Insulation and Energy Efficiency with ICF

ICF buildings are particularly energy-efficient since there is limited air exchange with the outside. The structures are free of drafts, which can be a problem in traditional construction, resulting in increased comfort. The cost of heating and cooling is lower in ICF construction than in traditional construction, giving it a significant financial benefit.

Because ICF buildings are airtight and effectively insulated, energy expenditures are typically around half that of conventional construction. Installing proper attic insulation, air-sealing the attic, and utilising energy-efficient windows and doors can all help you save money on energy.

Required Maintenance

Maintenance is frequently regarded as a need or an inevitable cost in a classic build-style home. This is particularly the case with timber frame construction. The ICF home requires little to no maintenance. Due to the structural integrity of an ICF building, future problems are avoided, and the home maintains its original condition over time.

The various advantages of ICF work together to achieve minimal maintenance costs. The airtightness prevents condensation and mould and ensures that structural and ugly wall damage is avoided. The concrete frame also ensures that the building does not deteriorate over time and retains its structural integrity.

Exterior Design Finishes

The ICF can be directly faced with render, brick or stone, timber cladding, or anything you desire! Prefinished sets of concrete panels can also be used to provide it with a modern minimalist appearance. People tend to render the ICF with an acrylic render which can be in any colour of your choosing. The coloured render means that painting is no longer required, and this saves money in the short and long term as the colour never fades or peels off.

Interior Design Finishes

You have complete freedom in terms of interior finishes. The rigid ties that hold the sheets apart feature anchor strips on either side of the foam sheets. These are for screws used to attach materials such as drywall, and furring strips, which can support a variety of finish materials.

ICF Construction use and disadvantages

Disadvantages and main use cases for ICF Construction

What about the disadvantages?

Of course, the ICF construction system is not without flaws.

Because ICF home construction is distinct from typical construction, fewer contractors have experience dealing with it. ICF must be correctly built to a professional standard to avoid any sub-optimal performance issues. Suitably competent supervision must be in place to ensure the system is properly built the first time.

It is absolutely vital that suitably experienced and qualified installation contractors carry out the work. 

When Should You Use ICF Construction?

ICFs are mostly used in new construction projects rather than retrofitting. They are fast to construct and offer numerous benefits, including strength, durability, and the ability to be well-sealed and insulated. ICF can also be used as an extension to a traditional block wall house. Care must be taken to ensure a proper joining detail is always achieved in this instance.

What Rapidform do

We provide full-service ICF construction packages to both residential and commercial clients. We can form and pour the base slab, and walls and provide the external rendering element. This means we can provide a full ICF package from a single sub-contract which reduces delays and minimises management issues onsite.

We have received all technical training and guidance required by ICF block manufacturers and provide a professional and expert service to our clients.

We are happy to advise and help in any way we can on your project journey.

Feel free to contact us.

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