A1 It is quite practical to design buildings up to three storeys as concrete masonry structures, i.e. without reinforcement. Any requirement for steel reinforcement will be dependent on the type, size and location of the building and will be recommended by your architect or structural engineer.

 

A2 The number of storeys or height of the building is limited only by the structural design and local legislation.

 

A3 We use designated pumpable RC 25 concrete with a slump of S2 or S3, with maximum of 10 mm aggregate. Concrete supplied under QSRMC or BSI quality-assured schemes.

 

A4 The size and light weight of components are such that they do not require mechanical handling, which helps to control damage and reduce waste.

 

A5 ICF components are delivered to site in packs or bags. They are light and easy to handle, and can be quickly cut with hot wire or hand saw as required. They interlock vertically and horizontally to form a continuous void that is filled with concrete.

 

A6 The two leaves of the formwork system are connected and held together by a matrix of plastic or metal connectors that become cast into the concrete core.

 

A7 During construction, it is necessary to support the formwork system and check for alignment during the pour, adjusting if necessary. Temporary bracing systems will be supplied by ICF Construction Ltd.

 

A8 The pump-grade concrete is placed into the formwork by means of a pump or skip and fills the system through gravity flow.

 

A9 The pattern of concreting will vary from project to project, depending on circumstances and resources available. A storey height pour may be completed in one operation, supplied by one or more ready-mixed concrete deliveries, working round the perimeter of the formwork several times until it is full.

 

A10 The thickness of the walls will vary according to the performance specification required. The concrete core may vary from 140 mm to over 300 mm depending upon the structural design, while the two leaves of insulation may vary from 100 mm to 300 mm depending on the thermal insulation specification. Consequently, total wall thickness may be between 240 mm and 600 mm thick and will be recommended by your architect or structural engineer.

 

A11 Lintels are usually light preformed components delivered as part of the ICF package. Manufactured to suit the various opening sizes required for the building, they interlink with the other components. Reinforcing bars are laid inside and the lintels are then filled with concrete at the same time as the wall is poured, integrating the reinforced lintel with the overall wall construction.

 

A12 The U-value of the walls varies with the thickness of the EPS, and can be as low as 0.10 W/m2K. ICF systems usually have a U-value of c. 0.20 W/m2K, significantly better than current standards.

 

A13 The thicker leaf gives additional protection to the structure and enhances the use of concrete’s thermal mass.

 

A14 The concrete cannot burn, and the EPS foam is selfextinguishing. In a really fierce blaze, well after the occupants have left, the main gases produced are CO2 and water vapour, with a minute amount of styrene, bromide and CO, which are less harmful than the compounds produced by the same volume of other building materials. The structural stability of the concrete reduces the risk of building collapse.

 

A15 All ICF systems have to achieve minimum fire performance standards to satisfy the Building Regulations applicable to the project. From a minimum 30 minute fire rating the design of the wall may be adjusted and fire tested to achieve the highest fire standards required.

 

A16 Buildings made with EPS have been in use on the Continent, North America and Australasia for over 30 years with no record of failure.

 

A17 Finishes are normally applied directly onto the surface of the insulation. Plasters and lightweight renders will adhere directly to the insulation. Timber, masonry, curtain walling and other claddings are applied over the insulation with appropriate mechanical fixings to the concrete core. Dry lining can be attached to the internal leaf using proprietary adhesives.

 

A18 The design process is quite practical and, once familiar with the system, most designers find it simple to use since there are fewer components involved, all manufactured to modular sizes. We can supply full technical information on request.

 

A19 ICF walls can be built off any foundation, held in position by their self-weight, just as for traditional masonry construction. The normal procedure would be to erect the initial lift or course of the ICF system around the perimeter, adjust it to the correct alignment and level and then pour in the first 150 – 300 mm of concrete to fix the position of the system on the foundations.

 

A20 Normally a waterproof or water resistant concrete is specified for that section of wall where the traditional DPC would be located. This may be specified and supplied by the concrete supplier, or a suitable admixture may be added on site prior to placement. Alternatively, a non-solvent based liquid DPC system may be applied onto the concrete at DPC level.

 

A21 Floors are normally built into the wall as the work proceeds, providing a solid connection between the two building elements.

 

A22

ICF Construction will supply and use a specialist scaffolding system which is used to align and support the walls whilst concrete is curing.

 

A23 Most ICF suppliers have their own systems that are designed to integrate with the wall construction, but alternative stairs and floors may be specified.

 

A24 ICF systems may also be used for internal walls. However, any internal partition system can be used, subject to making suitable connection to the ICF walls.

 

A25 An ICF building with roof installed and without cladding is sufficiently weather-tight to enable installation of internal services and finishes. Application of the appropriate cladding is required to ensure the long-term weather-tightness of the building and protect the insulation.

 

A26 Lightweight items may be fitted directly to the plasterboard or EPS with appropriate fixings. For heavyweight items such as kitchen cupboards, it may be preferable to drill and plug into the concrete core of the wall.

 

A27 The internal wall surface temperature is usually within 1 or 2 degrees of the room temperature, eliminating the risk of condensation. As a breathing (vapour permeable) wall construction, any interstitial condensation quickly dissipates when conditions improve.