We've come across the same thing in our home. In the kitchen we ended up knocking all the plaster down and starting from scratch. (that was before kids) Now we've got one of the bedrooms stripped as best we can upstairs. There have to be at least 5 caosts of wall paper on these untreated walls! HH was also pulling loose from lathe. My husband patched back to lathe with plaster buttons and covered with joint compound (or something of the sort) We are now searching for something to treat the walls with so we can paint over and start from new. Knocking down the plaster is a huge and very messy job, nothing we want to get into again EVER! Just read the post about something you can paint over the paper and sand and either repaper or paint. That is the option we are looking at now.