Bricking up wooden windows from the conservatory.

Hello, I would like to have a wood stove in my conservatory. The conservatory is made of wood. In order to get the chimney pipe outside, I now want to wall up a window. The window measures 1.5 x 1.9 meters. My idea is to remove the glass pane and build a wall on both sides. Inside with Ytong blocks and outside with clinker bricks. Between them, where the pane was, insulation. The window frame is made of wood. Now my question: Do I need to stick a foil between the outer wall and the insulation so that no moisture gets in and possibly damages the wood? Or how would you solve the problem? Best regards, Holger