I have separate cement stairs that lead onto my front porch. There is a wood panel in front of the porch that leads down to the first concrete stair - basically it is the same width of the stair. The wood goes right down to where it meets the concrete, but there is a small gap along the whole width of the stair where water can seep in between the base of the wood panel and the concrete stair. Is there a recommended method and materials to seal this space to prevent water from leaking into the house?