I have a 30 year old cedar shingle house that was originally stained with an oil base stain. A few years ago I had the house painted and the contractor used a latex paint over the stain. This paint is beginning to peel. Can I stain over the latex paint or will I need to have the paint taken off prior to using stain?
There isn't any benefit to applying a stain now that your house has been painted. A stain has to penetrate into the wood and the paint will stop that from happening.
If you want the stain back then you will need to strip off, remove, all of the paint. This will be an enormous amount of work compared to maintaining the existing paint. At this point it is economically better to remove the loose paint, spot prime with a good primer and repaint.