Landscape & Urban Design Issue 40 2019 | Page 49

CONCRETE & STONEWORK Wet-Cast Wet cast is similar to casting in plaster and provides a close-grained dense surface which can be stronger that semi dry cast but looks more like cement and less like natural stone. It allows precise rendering of fine detail and, for structural elements, the use of complex reinforcements. Wet-cast cast stone units usually require secondary surface finishing and typical techniques include acid etching, grit blasting, hand or mechanical tooling and polishing. Wet cast mixes use considerably more water than the semi-dry process and are generally a through mix of the finished face. The mix design is especially critical to the process and the finished appearance. After the wet-cast mix is poured into the mould, it is compacted using a vibrating table or vacuum casting, or increasingly by the use of self-compacting additives. Longer lead times are required for wet-cast cast stone as the process generally yields only one cast per mould per day. Fibre Reinforced Cast Stone This process incorporates fibre reinforcement into a higher water content mix that can be either poured or sprayed into moulds, from which the product is demoulded the following day. The incorporation of fibre reinforcing into the wet-cast mix increases the tensile strength of the finished product. A dense cast stone product with a close face texture is achieved which can be varied by the use of secondary surface treatments. Often fibre reinforced cast stone units are produced in thin sections which reduces the weight and associated manual handling issues, and offers the opportunity, through careful design and the use of specialist fixings, for retrofitting the fibre reinforced product to the structure. Longer lead times are required for fibre reinforced cast stone as the process generally yields only one cast per mould per day. What is cast stone used for Cast stone proves to be a sound investment that improves with the passing years. This is even more important in these changing times, which demand that our society moves away from disposability and looks to create long-lasting products that stand the test of time. We really value the artistic and cultural heritage of our gardens and buildings here in the U.K and around the world. As such, companies have sought to create a collection which preserves this history for future generations. Chilstone have been privileged enough to gain access to some wonderful pieces of stone work. They have carefully restored damaged stonework for many well- known clients, including Embley Park and Hever Castle. www.chilstone.com Follow us @ludmagazine www.landud.co.uk 49