The course of slates above the removed slate does not allow access to the batten needed to nail the slate back into position.
There are two methods available to allow the re-fixing of the slate:
Using a ‘tingle’ A bent metal strip of lead, zinc or aluminium is known as a ‘tingle’ can be used to reposition the slate securely. Cut a 25mm (1 inch) wide strip to the length of the slate lap plus another 25mm (1 inch), giving a total of about 200mm (8inches) length.
Nail the strip to the batten visible between the slates of the lower course - the row below the slate to be replaced. Always use galvanised or aluminium alloy nails to secure the strip to the batten. The slate should now slide into position and be at the same level as other slates in the same row. Now turn back the edge of the tingle to secure the slate into position. Make sure the upturned end of the strip is as flat as possible to add greater protection when covered with snow, stopping any movement of the fixture.
Using a Jenny Twin - A specially manufactured bracket known as a Jenny Twin can be used to reposition the slate securely.
This bracket allows a hidden clip to be fastened to the slate, giving an invisible repair. However the clip can only be fastened to battens and is therefore unsuitable for a slate roof where the slates are fitted directly onto a boarded roof.