Bradshaw contracts: building & groundworks   

                      Building/Groundworks and Civil-engineering  

All concrete pours need to be contained, to hold the concrete in place until it hardens sufficiently to hold its own shape. With concrete slabs, the freshly-poured concrete may be retained by existing features, such as walls, etc, or some form of temporary shuttering, also known as 'Formwork' may be required. On vertical concrete structures, the construction of the formwork can become quite complicated and is normally undertaken by specialist formwork erectors or formwork carpenters. Ground slabs are normally much less complicated and require only the simplest of formwork.

In all cases, the formwork must be sturdy and capable of bearing the not inconsiderable forces created by wet concrete, plus the weight and force of any vibration equipment. Any joints in the formwork should be taped or sufficiently tight to prevent matrix leaking out during vibration and/or curing. The tops of any shutter or roadform should be set so as to provide an accurate edge from which the tamper or beam screed can operate.

There are two main types of formwork used for casting ground slabs: Steel "Roadform" and custom-made timber shuttering.