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What You Should Know About ICF Building
A common misconception with an ICF building is that build costs are higher compared to traditional methods. However, rising material costs in the last few years means that ICF has increasingly become a competitive option. Add in the cost savings which are achieved on site such as short lead times, reduced labour costs and ability to build throughout most of the year can quickly balance make ICF a favourable options.
Once the homeowner has moved in considerable costs savings can be achieved through a reduction in energy usage and little requirements for maintenance or repairs over the property’s lifetime.
Simplicity is a key strength of an ICF building. To build the wall it only requires two main, common construction materials – the formwork and concrete. The formwork is created from two facing layers of insulating materials separated by a hollow core that is filled onsite with concrete.
The inherently adaptable system can successfully interface with standard and non-standard systems, materials and products. Typically, you will install most build elements after the concrete pour, although this does depend on your choice of ICF product.
Of course, high standards are paramount for any build. When insuring or mortgaging an ICF building, make sure the products have been supplied by an ICFA member.
For reliability during construction and to add an element of control to the product, our members will only supply their products to installers who are fully trained with their installation procedures. In terms of construction, ICF has several similarities to traditional build techniques that contractors will already be familiar with but with the advantage of being easier to construct.
It is the reinforced concrete core that provides the strength of the ICF building, yet the insulating formwork plays an important role. Not only does it provide high levels of insulation but it also, during the construction process, encases the concrete to enable it to cure in the optimum conditions that will enable it to build strength.
When you build with an insulating solid wall construction method like ICF, it can mitigate any potential problems with the concrete.
During the build process, you stack the ICF blocks to create the wall structure before pouring concrete into a hollow core. The blocks are made from an insulating material, usually EPS or woodcrete, which creates the ideal environment for the concrete.
The insulating material allows the concrete to set quickly but cure slowly, while at the same time protecting it from extreme weather. This stops the concrete from drying too quickly and reduces the chance of ICF walls cracking.
It is well-known that an ICF building can deliver excellent thermal performance, but what about condensation? The airtightness and continuous insulation of the structure prevents cold-bridging which is a major cause of condensation and mould. Systems supplied by ICFA members using their recommended concrete and design will adequately limit the risk of surface condensation while the elements in an ICF wall will not transmit moisture by capillary action.
If a building is strong, it is better adapted to withstanding natural disasters. With ICF, it is the solid concrete core that provides the building’s strength and, if designed and installed with rebar as specified by a structural engineer, can deliver greater impact resistance. This provides reassurance for the homeowner that disaster resilient buildings can withstand increased forces caused by a mass of water or even winds of up to 250 mph.
What about floor risk zones? Again, the concrete core can help. If correctly designed and installed, the ICF building with its concrete core has no voids to create a watertight shell. In the event of flood damage, the insulating material in the walls remains water-resistant which avoids long delays drying out the structure.
In the 50 years that ICF systems have been creating homes in the UK, fortunately, the number of times somebody has struggled to sell their home remains low. In mortgage terms, ICF properties are considered as insulated solid wall construction methods. ICF, as long as it uses a system manufactured by an ICFA member, has been approved by the Council of Mortgage Lenders as a standard form of construction. However, the lending decision is always at the discretion of the mortgage lender advancing the funds.
By building with ICF, it is the simplicity of the technique that aids its durability.
To build the wall you stack the ICF blocks which interlock into place with no need for mortar. Concrete is then poured into a central cavity in the block. The ICF blocks remain in place once the concrete has cured.
One of the big advantages of building with ICF is the way it supports the concrete core. The insulating material of the blocks aids the concrete by allowing it to set quickly but cure incredibly slowly, developing additional strength.
Third-party certifications show that the lifespan of building an ICF home should have a service life of not less than 60 years. However, concrete is an incredibly strong material that has been known to last hundreds of years. We only need to look back to the Romans to see real-life evidence of where the concrete buildings are still standing.
Of course, achieving this longevity is only possible when the building is designed and manufactured correctly. For this reason, we would always recommend working with one of our ICFA members. They will only supply their products to installers who are fully trained in their installation procedure. Our members will also work closely with contractors and designers to offer the right guidance and advice for the build.
When it comes to an insulated solid wall construction method like ICF, there are often questions about whether it will be difficult to extend or remodel the building in the future.
Most concerns stem around the difficulty in alterations to the inherent strength found in the concrete core of the wall.
However, with the right approach, extending or remodelling an ICF building should not be any more difficult when compared to traditional stick-frame construction.