Helo...i need to insulate my polycarbonate roof in my cheap conservatory. Its a rented house so i cant pull it down and build an extension and i get enough sun in my life so i dont need or want a clear roof (south facing). Its freezing cold in winter and sauna hot in summer, i was going to tape thick cardboard sheets to the polycarbonate but was wondering if a layer of bubble wrap against the polycarbonate then covered with cardboard would block the cold better than just cardboard on its own. I have seen greenhouses insulated with bubble wrap but of course that is to let light in for the plants. Having a cardboard layered ceiling may sound rough but i would paint the cardboard white and the conservatory is a useless room without doing something about the winter cold and summer sun hence the bubble wrap/cardboard. Many thanks for any replies 
