WEST Devon charity,Westden will hold a Sustainable Building Day today (Thursday), when new and traditional technologies for eco-friendly construction will be showcased. There will be demonstrations and a chance to have a go at cob building, lime repointing, traditional scantle slating, limewashes and greenwood turning throughout the day. Trade stands will include solar panels, heat pumps, timber framing, hydro electric, energy saving and insulated concrete building. The event runs from 10am to 4.30pm.