If the slate has broken then a replacement will be required.
Remove the existing broken slate see Removing a damaged slate.
Check with a builder's yard for a spare slate see Builders Merchants for local suppliers.
Otherwise look for a similar piece of slate.
Slates come in varying sizes and colours. Always try to get slate of a similar colour to
make the repair less conspicuous. The slate should also be the same thickness. Mark the
shape and size of the replacement slate on the back of a piece of slate and with a sharp
point of a tile cutter, score the surface as deeply as possible. Then with bevelled side
down, keeping the cutting edge in line with the side of a bench, use a bricklayer's trowel
to chop the edge.
It is important to use the side of the bench as a guideline. Repeat on
all sides needing to be cut. Once the tile is the correct size, mark the position of the
nail holes and drill them out, using a bit size similar to the nail size.
If you have a few tiles to cut, consider hiring a slate cutter or angle grinder to enable
good, clean edges, see Hire Shops.