The construction industry currently faces two big challenges – meeting housebuilding targets and climate change. Christopher Stride, Chair at ICFA explains how insulated concrete blocks could provide the ideal solution.
The wish list in construction is challenging and the need for affordable housing and tackling climate change becomes more crucial. While designers and developers are aware, they still need their schemes to meet construction and design intent and remain profitable. A potentially challenging prospect.
The construction industry are aware that Modern Methods of Construction should provide a solution due to their many notable benefits. But, with recent collapses of modular manufacturers, concerns over costs, and a lack of knowledge on build outcomes, it’s easy to see why MMC hasn’t been as swift as hoped.
However, combining the benefits of concrete with an intuitive MMC like ICF, a method that has been available for over 50 years, could solve the construction conundrum and extend concrete’s reach into the building sector.
What is ICF?
ICF is a solid wall construction method consisting of blocks made from two layers of an insulating material. In the UK, it is common to use Expanded Polystyrene (EPS) and Woodcrete.
The forms stack and interlock via a raised profile on the form’s edge. This is initially built up to the first floor before concrete is poured into its central cavity. Once cured, the build continues to subsequent levels until you achieve desired height.
Insulated concrete blocks offer flexibility, allowing a wide spectrum of designs, shapes, and technical elements through standard form sizes. You can achieve any “unusual” designs by hand cutting. The strength and same build method is also applied to structural elements like basements, supporting walls, or overhangs. Indeed, without the need for complicated structural solutions, some conditions such as corner windows and cantilevered openings, are easier to achieve compared to traditional methods.
Benefits of insulated concrete blocks on construction sites
Developers may hesitate with MMCs, but insulated concrete blocks offer seamless integration into standard sites. First, the manufacture is flexible, less capital-intensive and has shorter lead times when compared to other MMC systems.
On site, the simplicity of insulated concrete blocks can provide significant time and cost savings on a site. The building process incorporates the activities of up to four building trades in one step and, with blocks remaining in place once the concrete cures, it removes the time taken to strip the formwork. Developers can therefore opt for smaller teams while still achieving fast timescales with the potential to achieve a standard ground-floor structure in only a few days.
Training is also easier, and you can reach a competent standard on ICF systems quicker compared to other building trades. Without mortar, it’s ideal for apprentice training and reduces the need for expensive skilled bricklayers.
How insulated concrete blocks can boost concrete’s environmental credentials
Concrete, once seen as environmentally harmful, has cut emissions by 53% since 1990. The UK Concrete’s Roadmap aims to remove more carbon from the atmosphere than concrete produces.
Using insulated concrete blocks speeds up the roadmap. Their lightweight, stackable nature simplifies transport, reducing deliveries and carbon miles. When building, the system reduces the need for plant and equipment to minimise carbon emissions, dust and noise pollution. Plus, with the concrete hidden within the ICF wall, it is possible to further reduce the carbon profile by incorporating other waste materials such as fillers and aggregate.
The longevity of ICF structures is often overlooked when considering sustainability. During construction, ICF can boost concrete’s curing process. The insulating material of the formwork wraps the concrete enabling it to dry quickly but cure slowly to create additional structural strength with minimal cracking. A strong material can extend the lifetime of a structure, removing the carbon-heavy costs in terms of demolition and rebuilding. Even at the end of its life, if designed as concrete masonry without general reinforcement, it is practical to recycle the ICF and concrete either individually or as a composite material for further use in construction.
Reducing climate change
Fighting climate change is also about reducing the heating and cooling requirements. A lot of the existing UK housing stock wastes vast amounts of energy, which is why MMC, for all of its energy-efficient benefits, is so popular.
You cannot dispute the efficient properties of concrete for its ability to store energy and moderate indoor temperatures. Introduce a system like ICF and it can boost these energy-efficient credentials further. To hold the wet concrete in place as it pours, the block must lock tightly together. Once cured, the concrete sits in direct contact with the two layers of insulation to form a continuous and unbroken surface. This combination of factors increases the energy efficiency of the building while also enhancing airtightness levels and virtually eliminating thermal bridging.
The figures speak for themselves. There will always be some variations in energy efficiency figures for a building, depending on the ICF system chosen and design of the structure. An ICF building can typically deliver U-values between 0.30-0.11 and airtightness levels from 3m3/hr/m2 or lower.
Contact us for more information on ICF.