Only really Sunday available as we are out Saturday afternoon/evening (another firework display, believe it or not!).
The task for the weekend was to make the splitter box connector for the ventilation system. I had decided to split the outlet to the fan into two 100mm flexible PVC ducts to hopefully help reduce fan noise inside the room as well as reduce noise getting out. The idea is that by slowing the airflow down whilst retaining the volume the noise transmission is reduced. I'm not entirely sure how effective this will be but I'm sure it would not make things worse.
Anyway, this is basically an MDF box located between a couple of joists above the ceiling where the air exits the room. The rectangular duct attaches straight into the box and there are two 100mm round duct connectors at 90 degrees where my flexible duct will attach. First thing was to make the basic box shape and glue and screw this together leaving the top open. This was then put in situ to mark the location of the hole for rectangular duct. I had to unscrew and slide a joist out of the way as the box would not fit between the joists - I want it to rest above the recessed ceiling timber attached to the joists (see earlier post regarding recessing the first two layers of ceiling drywall). I had to clamp a small piece of timber to the roof support and use another quick clamp to hold the silencer box in position while marking. I then marked where the top edge of the joist was along the side of the box - this tells me the absolute minimum height I can cut in the 100mm round connectors.
The box was then taken down and the three holes were cut using the jigsaw. The rectangular duct feeds straight in so I just had to make sure that it fitted snug into the hole and protruded enough inside the box. For the round duct I used a couple of round straight connectors. I cut two round holes to allow a snug fit for the connectors. These were then glued into place using no nails.
All that was needed then was to line the box with something. I had a few acoustic foam tiles that I had bought a few years ago that would fit the bill nicely. I cut pieces of foam to size and glued and pinned them in place. Once fully lined I glued and screwed the top in place. One splitter box made:>>photo<<All that is needed now is to secure and seal joints in position above the ceiling - perhaps a job for the week. >>photos<<