Complete the slating in the normal manner to one course below the required position for the slate vent.
Temporarily fix slates directly below UTILITY SLATE.
Mark the position of the vent on the slates. The UTILITY SLATE should be as central between the rafters as practical. Ensure enough space is available for pipe work.
Remove temporarily fixed slates.
Cut the underlay in a “V” shape as shown. Fold back cut edges of underlay.
A Tegral Felt Weir (ref: TFW1) is available. This Felt Weir will give additional protection to the underlay cut. Neatly cut a 260mm long slot in underlay, at a distance of approx. 60mm above top of the slating batten. Slide the felt weir through this slot until the upstand of the felt weir is up to the bottom of the batten. Allow a minimum cover of 110mm between the felt weir and the underlay. Secure the felt weir by folding the top section of cut underlay over the batten and fix in place with a 20mm clout nail to the face or back edge of the batten. /

/ Cut the two slates marked earlier, these will be under the UTILITY slate. The amount to be cut from these slates will vary according to the size of the slate, the lap and gauge of the slating.
For a 600x300mm Tegral Thrutone Plus slate laid with a 110mm headlap the size of this cut is to be 75mm width x 150mm long from each slate.
Carefully reposition the two cut slates.
To insert pipe, simply cut a small “X” in the rubber grommet or a hole 10mm less in the diameter of the pipe’s insulation.
Insert grommet into the preformed hole in the face of the UTILITY slate. Push the pipe through this “X” or hole and pull back a bit to leave an outward facing cone.
Drill two 4.5mm dia. holes in the UTILITY slate centred on the slating batten. Position the UTILITY slate and fix with copper slating nails. Ensure tail crampion is in place and secured.
Trim slates to next course above the UTILITY slate to fit neatly.
Complete slating in normal manner /