1. Select the best position for the vent ensuring that it will not be obstructed from below by purlins or above by overlapping felt joints.
   
   The roof vent must not straddle a virtical joint, although it can stradle horizontal joints
   

         2)   Separate the lid section from the base unit (four off 8mm nuts with spring washers).

               Put the lid, washers and nuts safely to one side for re-fitting later.

           3)     Using the timber collar supplied, mark the internal area for removal (hole size385mm depth x 400mm wide).

           4)    From inside, drill holes 8mm in diameter in each corner and the middle to allow for a jigsaw blade.

           5)    Working from the inside and below, cut out and remove the marked section.

                  --------ADVISORY!  WEAR SAETY GOGGLES TO AVOID FALLING DEBRIS ---------

           6)    Fix the timber collar in place by using the four off countersink screws provided.

           7)    Working through the hole from the inside, align the base unit from above with the timber collar. Drill through the pre-drilled holes in the base unit through the roof and colllar using a 6mm drill bit (it is best to “G” clamp this in position). After drilling all of the holes (twelve off), remove the clamps and bring the base unit back into the building.                                       TIP: Use 7mm to widen and give clearance for the bolts through the wood only

           8)    Re-assemble the lid to the base unit and remove the protective tape from the foam sealing gasket arround the base. Clean any loose material from the felt and base unit and pass the re-assembled vent through the opening and place in position. (On steep pitched roofs secure with ‘G’ clamps.)

                 Open the roof vent (securing with the stay to allow unobstructed access) slide all washers back into place before inserting the 6mm stainless steel bolts through the frame, roof and timber collar.

         9)    Fit washers and nuts from the underside and lightly tighten. Working clockwise and starting from the centre of the top, begin to tighten the nuts. (It is best to go around several times to ensure an even compression of the sealing foam).

When correct compression is achieved, a deviation will be noticed in the base unit and around the bolt heads/washers in the timber collar, this is to be expected and has been designed to give the correct compression.

         10)     Fit the trim supplied to the internal cut edge of the roof.