<b><b>Barnes Wallis tested his bouncing bomb at the Building Research Establishment in Hertfordshire. Sixty years on and scientists are still mixing, ripping and burning at the site - and, as Stephen Hoare reports, many of their experiments are benefiting the housebuilding industry</b></b><br><b> Enter the gates of the Building Research Establishment at Garston near Watford and the first thing that strikes the visitor is the experimental Integer house built a couple of years ago for the BBC TV series Dream House as a test bed for intelligent green technology. Its glass panelled wall and photovoltaic cells conserve heat and energy while a garden pond and reed bed provides filtered grey water for all uses except drinking. </b><br><b><b>Dambuster design </b></b><br> Walk on past the offices and car park and you will find yourself in a bluebell wood where a tiny stream has been dammed to create a peaceful pond. The dam, a perfect scale model of the Mohne Dam in Germany, was built by Barnes Wallis during World War 2 to test the design of the famous bouncing bomb. <p></p><p>Water trickles where the concrete had been breached by a small explosive charge placed below the waterline. </p><p>For the past 80 years, the …