This is part six of a personal carpentry project whose stages were recorded on video: building a cat house for our two kittens. Here are the other parts:
In this video, you can see the three layers of insulation in the side walls: the 2 cm boards at the exterior, the polystyrene layer, and the 1 cm boards nailed over the polystyrene and secured to the 2cm exterior boards with wood screws. Most of the interior joints have already been caulked. Next up is finishing the interior, then sanding and treating the exterior.