Installing a Roof Ventilator ('Whirly Bird')
Installing the Twista is best done by a trained professional, ensuring that a weatherproof seal is restored to the roof, and that the Twista is operating at it's best. If you're a qualified tradesperson, you may like to follow these for whirly bird vent installation also. They are also available for download. You can get the whirly bird sale price here.
WARNING: you must be wearing long, elbow-high safety gloves while performing any installation to prevent injury from all sharp edges, and in case of the two collar halves detaching.
Select the desired location for your ventilator. Away from the street side of the roof is usually preferred by most. Count down to the third row of tiles from the ridge and carefully remove 2 or 3 tiles (depending on size) to provide an opening equal or wider than the outlet hole in the flashing panel.
Slide the second row of tiles below the ridge upwards to clear the entire width of the flashing panel. Position the flashing panel over the roof opening ensuring that the outlet hole sits more or less between the rafters. Position the top edge of the outlet hole in line with the edge of the top tile batten. Make sure the shortest side of the flashing panel is facing down the roof slope.
Bend down and form the two sides of the flashing panel to follow the side tile contours. Roll 40mm of the top edge up and over ensuring a return lip of 15-20mm is gained. Reposition the flashing panel over the roof opening. While holding it in place, slide the row of tiles you slid away back down as far as possible to hold the flashing in place. Please note that some specialty tiles (Terracotta and Swiss pattern for example) may require cutting to fit neatly.
Place the variable pitch collar onto the flashing panel. Ensure that the end with the two holes is at the top (see illustration). Slide the two halves of the collar against one another to vary the pitch angle. Adjust so that the top of the collar is sitting horizontally when viewed from all angles.
Secure the flashing panel and collar onto the roof by using the tree metal strap and self-tapping screws supplied. Carefully bend and position the metal straps at 12, 5, and 7 o'clock positions as shown. Screw the collar to the flashing panel through the front two straps (position 1). While pulling each strap down firmly, screw each strap to the roof timbers in the order shown (positions 2 & 3).
Using a hammer handle, gently form the bottom and side edges of the flashing panel to the tile contours. Ensure that there are no large gaps between the flashing panel and the tiles. Re-check the level of the collar and adjust if necessary. Screw three screws into the collar variable pitch slide seam (joint) directly above the two metal straps at the front (1 and 2) and slightly to the side of the rear strap (3). Ensure the screw pass through both layers of metal in the seam and that they don't interfere with the lower fan blade. Note: for high wind areas silicone can be used on the inside seam to bond both layers of the metal collar. Ensure that oil film is removed).
Place the rotor head onto the collar, aligning one of the four fixing points with the centre of the rear strap where it is folded over the top of the collar. Fix the rotor head in place using four self-tapping screws supplied. Drive each screw in once and then unscrew all the way out and then re-screw it again to ensure a good, stress-free attachment. Note: DO NOT over-tighten these 4 screws, otherwise the base ring will crack in time. The screw heads must GENTLY touch the outside body of the ring. It must not place any pressure onto the base ring.
Please note: We recommend that all installers are experienced in the installation of whirly bird style roof ventilators and that they have a roof plumber's or builder's license, or that they are professional tradespersons. The supplier and manufacturer does not take any responsibility for installation work or consequential damage to ventilators of installations carried out by persons or organisations other than their own direct employees.