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Questions:
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Is steel reinforcement always required? |
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What is the specification for the concrete? |
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Do I need to compact (poker) the concrete? |
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Answers:
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The Logix system is so straight forward that it can be tackled by most people after attending one of our training courses. The course covers the therory and practical issues you'll come across when building with ICFs, and is compulsory for any one building with Logix. We do charge for the training, but the charge is refunded upon placing an order. Alternatively we can also put you in touch with a contractor experienced in ICF construction, if you don't want to get your hands dirty. | |
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Yes, he will need to do the structural engineering calculations for the design of the load bearing walls. | |
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Is steel reinforcement always required? |
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In many cases, in above ground structures, no steel reinforcement will be required, except over windows and doors. The decision of whether steel reinforcement will be needed is made by the structural engineer. | |
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What is the specification for the concrete? |
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Above ground C20/25 is typically used, to give adequate protection to any steel used, while below ground C30/35 is more commonly specified. We try to keep the mix as standard as possible to help control costs. A typical mix would have less than 0.7% water and a target slump of 110-125mm, using 10mm aggregate. We recommended sourcing your concrete from an ISO 9002 quality-approved ready-mix supplier. | |
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We recommend that people new to building with Logix use a mix of concrete that contains uses ordinary portland cement (OPC or cemI). Using OPC gives a concrete that flows well, gains intial strength quickly once placed, and is is easy to work with. With more experience its possible to use blended cements which used recycled materials to replace some of the cement. Contact us for further information. | |
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Using forms made of EPS foam instead of traditional plywood does not alter the basic guidelines for placing concrete. Concrete can be compated either by hand, with a steel rod, or by using an internal vibrating poker. To do a good job by hand takes a lot of effort, and dilligence, and is only effective on small layers of concrete. The best method is to use the poker to compact the concrete, ensuring that the concrete entirely fills the forms and that the air within the concrete is removed. | |
| Removing air trapped in the wet concrete is important for a number of reasons: | |
| a) 1% of voids in the concrete equates to a 5.5% loss in strength | |
| b) The life of steel reinforcement used to create lintels etc, is dependant on minimising the corrosion caused by ingress of moisture through voids with in the concrete. | |
| c) unless otherwise specified the structural calculations will be based on the assumption that the concrete is properly compacted and void free. | |
| Using a poker also has the following benefits: | |
| d) It allows the use of a wider range of concrete slump, from 75mm upto 175mm, by improving the way stiff concrete flows locally. | |
| e) It helps concrete flow into all the awkward corners and under windows cills etc. | |
| The concrete Society, The Building Research Estalishment and British Standards all stress the importance of proper placement and compaction of concrete. | |
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As with any building project a good architect can really help you get the finsihed results you dreamed of. | |
