I have an open wooden ladder style staircase in my Victorian house which is very steep and slightly slippery. I would like to find a way to cover the treads in something like sisal or coir which would make the steps less slippery, but without doing major DIY or putting vertical uprights in. Does anybody have any suggestions as to how to do this? Or any pointers to websites or companies who might manufacture this kind of thing? Any suggestions much appreciated!