In the second part of this feature, Nudura outlines best practice for architects looking to detail and construct buildings using insulating concrete formwork

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One of the advantages of insulating concrete formwork construction is that it is comparatively simple to design and install. As with any building system it is important that architects are familiar with and knowledgeable about how the system is designed, constructed and monitored on site. It is also useful to know what manufacturer resources are available, as this can make the design process easier and faster.

Detail design
Nudura has a comprehensive library of approved building details that can save architects time and ensure they do not have to design each element from first principles. Augmenting this resource are technical tables and charts, as well as a powerful BIM Library.

The structural tables are based on Eurocode 2 & 8 and cover below- and above-ground works up to a height of five-storeys. The system has been used in Canada to construct buildings of 25-storeys, but is capable of reaching 40 storeys. Lintel tables cater for structural openings of up to 6.3 metres and loads of up to 60kn per linear metre (larger openings are possible, but require structural design). The wall thickness chart is designed to help architects and engineers select an appropriate core thickness for optimum wall performance, ie to yield the most efficient combination of concrete and steel for the required condition.

Stack heights with ICF construction can be particularly important when considering aspects such as footing elevations to grade, brick finishes relative to grade levels, and floor bearing heights relative to finished grade and each other. The wall height chart indicates optimal stack heights for designing walls up to 11 metres high.  Higher walls are possible by adding multiples of the form height (457mm) to the 11-metre wall. By nature of the material, it can be easily cut to accommodate any desirable height.

With regards to BIM, all files are configured to work with Autodesk Revit. The project/template files comprise a platform of wall types (with accompanying properties) to begin the design process. The project and template files also allow specifiers to transfer Nudura ICF wall types into existing building projects. 3D form unit models/families enable specifiers to view the geometry of each form unit from any angle. There are also dwg files of all 3D form unit profiles/families to allow users without Revit to view the form line-up in three-dimensions.

Building from the ground up
Work on site begins by casting the foundations of any type. Both slab and step foundations are easily accommodated using ICF. In terms of footing size, specifiers should remember that ‘edge projection distance’ is the distance from the concrete wall surface inside the form to the footing edge – not the exterior wall surface of the EPS foam to the footing edge. Vertical reinforcement dowels placed in the footing or slab edge provide lateral support at the base of the wall.

Wall assembly
The EPS form units are stack bonded on site with horizontal steel reinforcement inserted at each course, or as specified by the engineer. Standard forms are cut to suit the wall length and butted to preformed corner or T-form units. A proprietary alignment system is erected to facilitate safe access and alignment of the form assembly during concrete pouring. The structure typically remains in place until lateral connections to the wall are made. For basements, Nudura supplies an EPS-compatible peel-and-stick bitumen membrane that is applied to the outer face of the wall to guard against moisture infiltration as part of a Type A tanking ststem.

Wall openings and concrete placement
Window and door openings are placed in the wall using formwork that is able to support the concrete during placement. Upon reaching the desired height, vertical steel reinforcement is inserted into the wall cavity. Concrete pouring is recommended using a boom pump and internal vibration to ensure even placement and consolidation. The concrete can be poured in any weather due to the insulating properties of the EPS formwork.


Floor and roof connections
Once the concrete has cured, wall-to-floor and roof connections can be made. Floor types typically used in conjunction with ICF walls are in-situ concrete, hollowcore planks, timber, and block and beam.  Roofs tend to be timber or light-gauge steel. Concrete roofs are easily achievable.


Services installations and finishes
The EPS-faced walls are chased to receive electrical wiring and pipework (up to 50mm in diameter). According to Nudura’s International Sales & Business Development Director Jean-Marc Bouvier, one of the key constructional advantages of ICF is that it takes external cladding off the critical path. Windows and doors can be installed as soon as the concrete is cured, ensuring a weathertight envelope.


A wide range of external facing materials can be applied to ICF structures, including brick, stone, render and timber, as well as steel, aluminum and cement cladding panels. Specifiers should note that screws must be used in place of nails when it comes to installing external facings. Plasterboard is the most common internal finish and can be installed directly onto the walls using 42mm plasterboard screws. Acrylic/silicone render can be used in flood-prone areas.

Site inspections
“Architects should come to site as often possible”, recommends Bouvier. “This not only allows them to check flashings, weather seals and other details, but also that they are happy with the overall position of windows, doors and other features. The flexibility of ICF means that changes on site are easy to accommodate up until the concrete is poured.” Only properly trained and accredited Nudura installers can use the company’s products, providing peace of mind to specifiers and clients.

Contact Details
For more information on Nudura ICF systems please visit the website.