Designing an ICF home
Anamika Talwaria investigates how you can create a bespoke property using insulated concrete formwork
Could insulated concrete formwork help you create the exact style of house you want? Anamika Talwaria looks at what’s possible with this build route
ICF is an intuitive modern build method involving hollow blocks, typically made of expanded polystyrene (EPS), which slot together to form the structural skeleton of your home. These are then braced and filled with readymix concrete to create an ultra-strong, high performance structure. The lightweight units can be manipulated into whatever shape your design calls for with ease, making it an ideal system to create architecturally interesting homes.
“ICF is historically popular when aiming for slightly wacky building shapes,” says Miguel Jaen, technical sales manager at Jackon UK. “Round walls and oblique corners are easily achievable, as the EPS formwork can be cut and shaped to create different radii and angles.” Some ICF systems, like Nudura, also offer blocks in pre-cut forms, perfect for creating angled and curved walls. This makes it even easier for a self builder to create a unique dwelling. Effectively, the main limit to ICF is your imagination (or that of your architect or designer).
Selecting the right designer
With the above in mind, it’s advisable to choose a designer who is familiar with the system. “One of the most common mistakes we see is that architects try to apply traditional construction methods and details to ICF projects,” says Christopher Stride, chairman for the Insulating Concrete
Formwork Association (ICFA). Your designer can add heaps of value to the scheme just by knowing more about the possibilities and limitations of the material. If you’re working with someone who’s used ICF before, they’ll also be able to minimise waste and improve the efficiency of your scheme by designing to the right block sizes.
ICF is very versatile, so if you’re looking to create a super contemporary house with round walls, vaulted ceilings and a crisp render, you just need to make sure that you have a designer who understands your vision, and knows how it can be achieved with this material.
Creative architecture
It’s also easy to achieve wow-factor features with ICF.
“The system’s flexible nature means that some aesthetic considerations, like corner windows and cantilevered openings, are less difficult to design as they do not require complex structural solutions,” says Christopher. So, if you’re looking for a double-height entrance hall or roof overhangs, this build method could be a great solution. A
lot of this comes down to ICF’S inherent strength. The steel-and-concrete core can support a lot of weight, making features such as large spans of glazed doors and open-plan layouts easy to achieve. What’s more, elements such as balconies and brises soleils can potentially be bolted onto the concrete core.
As with other build systems, sometimes a combination of materials is required for a successful result. You might need to factor in steel beams or posts, for example. This is where it pays to work with a designer and a structural engineer who are both familiar with the material, as they can advise you accordingly with a viable solution.
Building downwards
Basements are on the rise in the UK as a way to make the most of your plot while retaining valuable garden space. Plus, the stereotype of the cold, damp cellar is so outdated! Creating a basement from ICF means it will be inherently insulated, with the blocks providing an in-built layer of thermal protection. What’s more, ICF is quick and straightforward to waterproof, making it a cost-effective option for achieving high-quality living space.
We constructed a basement at the Build It Education House, using Nudura blocks from ICF Supplies, which hosts our plant room and home cinema. We wanted to maximise space, while sticking to our strict plot passport – check out www.buildit.co.uk/visitourhouse to book your visit and see how cosy a subterranean level can be!
External finishes
Subject to planning constraints, you can finish the outside of your ICF home in any style you fancy. “Silicone-based renders are very well suited to the EPS outer leaf,” says Miguel from Jackon UK. Render can be applied directly to the polystyrene, making it a speedy and cost-effective way to finish off your home. “Equally, timber or metal cladding can be anchored to the concrete core of the house,” says Miguel. “You could even go for a brick slip or stone facade – whatever you choose for the outside, rest assured it won’t compromise your property’s thermal performance.”