10 Pros and Cons of ICFs in Self Build Homes

When you start planning your self build project, through your research you will quickly gather that at some point or another you are going to have to make a decision on your chosen self build construction method. Making this decision can feel quite daunting, particularly if it is an area you’ve never really researched before or you’re feeling a bit swamped in information.

Before delving into the core differences and pros and cons of each option out there, you should really ask yourself what it is that YOU want from your self build home, and the features of your home that are going to be most important to you. For example, do you have a budget you need to keep to? Are you looking for the easiest and quickest route? Is an environmentally friendly option important to you?

Once you have an outline of your core requirements for your project, this will really help you narrow down your best options.

We’ve put together some handy guides on the top Pros and Cons of all construction methods, to give you an idea of some of the major selling points and pitfalls of various options. These options include:

In this article, we are going to focus on ICFs.

ICF homes

What is ICF Construction in Self Building?

ICF stands for Insulated Concrete Forms, which is a construction method involving interlocked foam blocks to create the walls of your home. These are then filled with reinforced concrete to create a strong and durable structure.

In the context of self building, there are some unique benefits that ICFs offer and they are becoming ever popular as they are easy to use, quick to build and durable. To construct, you will need to purchase the foam blocks, concrete and reinforcing steel and then the blocks are stacked together like Lego pieces. The reinforcing steel is placed and concrete poured into the forms to create the strong ICF structure.

When you are making a decision on ICFs, you should consider the positives and negatives of this method to see if they are a good fit. This article aims to lay the pros and cons in a simple way.

If you are looking for more tailored advice on self build construction, please feel free to reach out to us.

Pros of ICFs for Self Build Homes

1. Energy Efficient

There are many modern self build construction methods that provide better energy efficiency than traditional masonry, and ICFs are one of them. As they are highly insulted, they offer a high level of energy efficiency, keeping your home cool in the summer and warm in the winter.

There are a few features that contribute to their great insulation: airtightness, thermal lag and continuous insulation

icf energy efficient home

ICF structures are very airtight, which leads to generally better energy efficiency. Thermal lag is the delay of heat transfer through a wall, which helps preserve the indoor air temperature as the outside air cools. ICF chamber studies have shown that thermal lag is better on ICFs compared to their counterparts.

In addition, continuous insulation construction in ICFs helps prevent thermal bridging, which occurs when there are gaps in the insulation. Because ICFs have a layer of insulation that is installed continuously over the entire exterior surface of the building envelope, this helps prevent heat loss and condensation.

If you are keen on an energy efficient build, ICFs could be a great option. SIPs are another option to explore with this benefit as well.

2. Soundproofing

Planning to set up your self build home near a train line or on a flight path? ICFs offer great soundproofing in comparison to some other construction methods. This is down to a combination of their thick walls, insulation and high mass.

The foam blocks are very dense which, in combination with the insulation, gives the build sound-dampening qualities that are unrivalled when compared to masonry construction or timber frame homes.

If soundproofing is an important consideration for your self build home, ICFs could be a consideration.

3. Durability and Weatherproofing

The rigidity and strength of ICFs make them extremely durable and capable of withstanding extreme weather conditions, such as storms or high winds. ICF builds are more resistant to wind damage compared to other methods thanks to its reinforced concrete core and steel.

They are also more resistant to water damage and moisture damage as the foam insulation built into the blocks prevents water from penetrating the walls, and the concrete provides a barrier against rain and sleet.

Some areas in the UK experience more strong wind and rain than others, so if you are planning your self build project in an area with this type of climate, ICFs make a sensible and ideal choice for comfort and safety.

4. Versatile Build & Design

ICFs are very versatile as they can be used not only for the walls of your self build home, but for the floors and roofs. They can be cut and styled to fit a variety of different designs and architectural styles, whether you are looking for a traditional style home or a modern and sleek design.

Despite ICF being built around rectangular forms, exciting architectural features are possible such as large vaulted ceilings, curved walls and even cantilevers. Thanks to the strength of the concrete core, you can incorporate large window spans into your designs.

If you are looking for a self build option that gives you a lot of creative and design freedom, ICF construction could be a great option. It would be worth speaking to a self build architect to talk through your design ideas and they will be able to advise on the most suitable options.

icfs for self build homes

5. Reduced Construction Time

Thanks to the lightweight, easy-to-handle blocks, ICF can generally be quicker to assemble compared to other methods, but this can obviously depend on a number of factors such as the complexity of the project, weather conditions and the skill of the builders.

On a simple project, an ICF self build for a single storey can be completed in as little as 3 days, which is a lot faster than brick and block. For time conscious self builders, ICF could be a suitable option.

Cons of ICFs for Self Build Homes

6. Self Build ICF House Costs

ICF self build home costs are slightly higher than other construction methods by around 15-20% overall. In 2023, the general ICF house cost for the blocks is around £35 per m2.

We’ve gathered some overall ICF cost estimates from around the web to give you a better idea of the range you can expect to pay for an ICF self build:

It’s worth noting that these estimates are the minimum price you can expect to pay, and don’t include additional costs such as paying for builders. Be Trade Savvy estimates that overall, ICF or SIPs add an additional 1-3% to the overall construction cost compared to standard brick and block..

If you are looking for a budget friendly self build option, you may consider looking at some other more cost effective options. However, in the long run ICF construction can provide better energy efficiency which can contribute to savings in the long term.

icf self build home

7. Environmental Concerns

The use of concrete in the structural forms does raise a question on the environmental friendliness and sustainability of this construction method. In general, ICF blocks are around 15% concrete.

While concrete is a largely used material throughout the UK and the world, the manufacturing process and industry for concrete contributes around 4-8% of the total carbon dioxide emissions in the atmosphere, which is very significant. Although the ICF construction is very energy efficient, therefore contributing to a lesser consumption of energy over time, the use of concrete does mean that there are some environmental considerations for this method.

If you are concerned about the environmental impact of your self build, it may be worth considering a more eco-friendly option like SIPs or Timber Frame.

8. Less ICF Builders & Specialists

As ICFs have become more popular, more ICF specialists have appeared throughout the UK. However, when compared to other methods, ICF specialists may be few and far between, and the construction requires specialised skills to install and work with the forms and concrete

ICF construction is a relatively new technology, and it requires a different set of skills and expertise compared to traditional construction methods. There is no evidence to suggest that there is a lack of ICF builders in the UK, but there certainly are less when compared to masonry. This may lead to longer lead times or higher costs for self builders who wish to pursue this construction method.

If you are conscious of lead times, we recommend checking in with local specialists in your area to get an understanding of whether it’s a suitable method for your timeline.

building with icf blocks for self build homes

9. Remodelling Limitations

Making changes to your ICF home may require some additional considerations compared to other construction methods, but this will obviously depend on the specific project and scope of work.

The insulation and moisture barrier provided by ICF construction will sometimes make it more difficult to change to the electrical or plumbing systems, as accessing the lines that run through the foam insulation can require additional effort and careful planning compared to masonry.

Another consideration is modifications made to the walls, as these need to be done carefully and with the guidance of a professional experienced in ICF construction. The load bearing walls are an integral part of the structure, and so changes must be given proper thought, which doesn’t make changes impossible, but just means that they do need thorough planning.

10. Thickness of Walls

The thickness of the ICF blocks is not an issue in and of itself, but if you are working in a small area with a limited amount of space, this may not make ICF the ideal option.

Particularly if you are building in the middle of a city or within quite a compact plot, the limited build space and bulky ICF blocks can inhibit buildings of this type and therefore, may not be ideal for these types of self builds or other residential builds.

Building Self Build Homes with ICFs in the UK

ICFs are quickly becoming a more and more popular choice for self build projects in the UK, with more people looking for ICF construction as their chosen method. The energy efficiency and strength of the design will offer many wonderful benefits for homeowners, but they might not be right for everyone.

If you are looking for some more tailored advice around your self build project, or are generally feeling a bit swamped in information, please reach out to the incollective team. We have years of experience in self build architecture and design, and have worked on many different projects.

Head over to our online contact page, or give us a call on 023 8244 3801

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