We spent a day or so making an air duct that will extract the hot air from the Conservatory. It needed to go inside the wall between the window and the door, going all the way from the concrete floor level and right up to the top of the wall and beyond.
We used more of our supply of 25mm thick aluminium coated insulation PU foam board, careful to retrieve ones that had no defects or wrinkles in the surfaces and sliced them up into various width strips so we build the four sides of the ducting.
But first, we had to dig out old insulation boards because we filled the space up before we remembered that we were always going to have an air duct here! It measures approximately 250mm wide by 150mm deep in the interior which is equivalent to very nearly five 100mm diameter pipes so it will have a good capacity to carry lots of air at minimal pressure loss. We even “bent” the last foam board to provide a sweep bend at the bottom of the shaft, to help the air molecules to change direction smoothly. We did this by slicing every 30mm through the back paper layer and snapping the foam to make it wiggle and still be attached to the front layer of the shiny aluminium paper, then taping this floppy piece around a large circular drum that had about a 500mm diameter and finally, spraying tiny amount of expanding PU foam into the opened up cracks to glue it all back together again.
Conservatory-extract-duct-in-P-wall-back-and-sides
We put aluminium 50mm sticky tape across all the joins inside the vertical shaft to reduce turbulence and air flow rates and finally put on the front lid, made up of three pieces and joined with more of the aluminium tape.
Conservatory-extract-duct-in-P-wall-complete
Conservatory-extract-duct-in-P-wall-exit-under-the-floor
Conservatory-extract-duct-in-P-wall-inside-the-duct
Eventually, we will make a chamber at the bottom to translate the rectangular duct into four 100mm pipes that will go across the floor towards the corner of the Great Room with the Kitchen and go back up to the first floor to join into the main air duct running down the whole building. The upper section will be finished off when we have working platforms positioned for when we need to fill in the roof rafters with more insulation foam boards.