Alternate Methods of Construction | Insulated Concrete Formwork



As part of a series looking at alternative construction methods we delve into what ICF is and why you may want to consider using it. Using alternative methods of construction to the more popular methods (around 70% of new builds are still brick and block) can help combat the major issues of time and cost. Today we'll be delving into Insulated Concrete Formwork (ICF) and when it might be the most suitable to fulfilling the potential of your build and site.


What is Insulated Concrete Formwork?

ICF is a system where inter-locking hollow blocks, typically made from polystyrene, are stacked to form the structure of the building, reinforced with rebar and then filled with concrete. The process is drastically simpler compared to many traditional and offers a myriad of benefits. Blocks come in a wide range of shapes and can be clad in a variety of materials, making ICF builds aesthetically indistinguishable for builds constructed from any other method.

ICF can be used on a range of projects from single homes to schools, and some systems are suitable for buildings of up to 19 storeys high. A number of suppliers offer courses on how to build with it and certifications, making it possible for non-construction professionals undertake the majority of the process.


What are the advantages?

  • Wall, insulation and structure are placed in a one step, reducing build time and labour costs drastically. The ease of construction also means it is suitable for self builders.
  • The ability to create any form and apply any cladding makes the final build indistinguishable from any other traditional constructed building.
  • ICF builds are incredibly durable. Buildings can withstand hurricanes and earthquakes, which may not be much of a factor here in the UK, but they also have a typical fire rating of 4 hours and retain structural integrity.
  • Because of the polystyrene block and concrete composition ICF builds have excellent thermal and noise reduction performance. Homes can achieve Passivhaus certification, meaning that no active heating or cooling systems are needed because of the insulation properties.

With all these benefits there are other factors to consider that may be detrimental to certain projects. Upfront cost is higher as materials are more expensive, although this may be inconsequential because of the savings made from the lack of ancillary costs and long term energy savings. The high performance the finished build also comes at the cost of space due to the thickness of the blocks, meaning it may be worth considering alternative methods if floorspace is a premium. It is also worth bearing in mind that any extensive remodelling will result in having to cut through solid concrete.

There is much to like about ICF, and if you are participating in any construction projects where long term performance and minimal time on site is vital you may want to put it at the top of your list to investigate.


One of our current projects using ICF is Wayland Avenue. ICF was chosen to provide a stronger structure and save costs, as it was cheaper than cavity walls as well as higher performing.