Air tightness

Just getting to start the external wall insulation took some effort - making sure holes, vents etc in the wall were blocked up (or in some cases filled with foam), and making sure key areas were reasonably air tight with blue felt and blue tape.

The main air tightness barrier will be on the inside - the plaster on the brick walls, and a breathable membrane in the attic room.

However, we want to achieve a pretty good level of air tightness on the outside so that air doesn't get into the insulation layer from the outside and "wick" heat away from the house.