Self Builders – Build With ICF

Congratulations on deciding to build your new home! Now it’s time to choose the best materials to realise your dream self build project. The build method you choose for your home will have implications on almost every level. We look at why you should build with ICF and how choosing this simple yet reliable construction system can help to deliver a straightforward project.

Designing your Home

Self-builders are renowned for bringing individuality and vision to their dream property, but some materials can put limits on the imagination.

Insulating concrete formwork (ICF) is a Modern Method of Construction (MMC) structural system that can provide significant benefits for your self-build project. ICF construction gives self builders many creative options:

The system is simple and very flexible for almost any design.
It works for traditional farmhouses and modern homes with special shapes or curved walls.
The strength of the system makes it suitable for the entire build including retaining, above and below grade walls, basements and even swimming pools.

What is ICF Construction?

Insulated Concrete Forms (ICF) are an on-site system of large blocks or formwork made of an insulating material. The building process is incredibly simple with the ICF blocks stacking and connecting to create the external wall without the need for intermediate bedding materials such as mortar. Once in place reinforced concrete is poured into the central cavity to create a strong and highly energy efficient home.

Once the concrete has set, the Insulated Concrete Formwork blocks remain in place to provide a continuous insulation that wraps both the inside and external walls of the building envelope.

In the UK the most commonly available ICF systems are expanded polystyrene foam (either EPS panels or moulded EPS systems) or mineralised recycled wood chips mixed with cement known as woodcrete units.

What is ICF Construction

Benefits of ICF

ICF systems offer numerous benefits to selfi-builders including:

Energy Efficiency – these systems are typically chosen by self builders looking to reduce their environmental impact. An ICF building offers superior energy efficiency which, over the lifetime of the ICF building, will dramatically lower energy bills and and reduce the carbon footprint of your self build project. ICF structures offer superior thermal performance with ‘U’ Values as low as 0.10W/m²K. The dense concrete structural core with layers of insulation provides thermal mass benefits that keep the building warm inside in winter and vice versa in summer. Insulating Concrete Form systems are regularly used when looking to build to Passive House standards.
Strength of Build – Protecting your household is an important consideration when designing your new home. The reinforced concrete inside the ICF blocks can be used to design a building that will stand up against the elements. This includes flood risk regions, earthquake zones and areas that suffer severe weather such as heavy storms and high winds up to hurricane and tornado level. The system also offers a fire resistance rating of up to 4 hours.
Healthy Environment – ICF buildings are airtight by design. This reduces dust and pollen inside. People with allergies or chest problems will benefit.
Acoustic Performance – The concrete cores in ICF are dense and thick. They provide excellent sound insulation. This greatly reduces unwanted outside noise.
Minimal Maintenance – Normally, ICF walls need no maintenance during the building’s life. Only the inside and outside surfaces might get minor damage.
Easily adapted for owner’s need – Reinforced concrete frames create space without extra loadbearing walls. This makes it easy to remodel and upgrade floor layouts in the future. You can add extra floors if authorities approve. You can also add extensions and extra openings.
Compatibility – ICF systems can successfully interface a wide spectrum of different construction systems, materials and products.

How Much Does it Cost to Construct an ICF Building?

Material costs for ICF are usually higher than for brick and block or timber frame systems. However, builders save money during construction by avoiding costly delays. Standard ICF blocks, which can be used in most designs, are pre-manufactured off-site and typically delivered to site within three weeks ready for assembly.

ICF blocks are lightweight and there is a reduced need for expensive heavy plant equipment. The simple and fast building method of ICF construction needs fewer skilled contractors on site. Builders can make a watertight property faster than with traditional methods. This enables follow-on trades to enter and start putting in utilities and finishes in place much earlier. The build programme can also continue in almost all weather, even through the wet winter months.

ICF Costs

How long will it take to build an ICF home?

Building with ICF means that large wall areas can be constructed very quickly and easily and typically a standard ground floor layout of home can be constructed in only a couple of days.

Hiring an experienced ICF installer helps ensure a fast and successful project. But many self builders choose to do the work themselves to save money because the system is simple. We recommend buying your building system from one of our ICFA members who will offer training and support throughout your project.

ICF Mortgage, Insurance and Planning Acceptance

Insulating Concrete Form systems supplied by ICFA members are recognised by ICF systems supplied by are recognised by The Valuation Panel of the Council of Mortgage Lenders for mortgage purposes as a standard form of construction.

Be aware that Modern Methods of Construction (MMC) such as Insulated Concrete Forms are considered as non-standard build systems with insurance companies. With the growth in MMC there are plenty of options available, but you will need to approach insurance companies in advance and understand their requirements to detailing.

The ICFA has worked closely with leading mortgage and insurance lenders. Head to our ICF and Self Build Mortgages page for more information on getting a mortgage on a self-build project.

ICF and Self-Build Mortgages

Where to Buy ICF?

Not all ICF products are the same and the size, design and material of the product can vary. The ICFA recommend talking to ICF suppliers as early as possible to identify the best product for your project and to discuss areas that may require special consideration. Also see our guide on How to Build with Insulated Concrete Forms to find out more about building with this Modern Method of Construction.

Get Advice from the Insulating Concrete Formwork Association

If you have a query or would like further information, please contact the ICFA here.

ICF FAQ

Insulating Concrete Formwork

Frequently asked questions

Everything self-builders need to know about ICF construction.