Hi, the riser is quite old and well split as you say. Can you access the back of the stairs via a cupboard? If so you could force some wood glue into the split then place a wooden plank over the riser and glue and screw it to the riser making sure the screws used are the right length so they don't protrude through. If you can't access the back you could do a similar job using a thin sheet of plywood, say 3 or 5mm and glueing it directly onto the riser and tacking it with suitable small tacks. For the glue to work properly you would have to remove all the old paint and varnish right down to bare wood again. Use paint and varnish remover and a scraper and finish off with a hand held electric sander. Good luck, Bob
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