With Open House London next weekend, the Observer casts a useful glance over the eco-friendlier addresses taking part, including John Broome's (author of "The Self-Build Book") Lewisham home, built on Walter Segal post-and-beam principles. In Hackney, you'll be able to look round the RIBA award-winning In-Between House, built by architects Annalie Riches, Silvia Ullmayer and Barti Garibaldo - glass-fronted, timber-framed, and insulated with wool and paper. It's a good read, especially if you're planning your weekend. More, here.