kinda off topic but not
without a doubt lime based plaster has to breath. It's part of the hydraulic process or life of the plaster. 99.9% of wall condensation issues occur from the type of paint used. A catch 22 of sorts. Property owners typically own with the "seal the wall" philosophy.
Consider this....the brick motor for that time period was also lime based. As the humidity rises outside the amount of moisture the lime holds increases as well. Both in the brick mortar and then the plaster swells. As the humidity goes down outside so does the amount of moisture carried by the lime, and the lime contracts.......the only thing is...at times the weather changes quicker than the evaporation process, and if the moisture in the lime needs to escape, it will try and escape through the interior walls....if the walls are sealed with paint based with oil, condensation can occur.
Last spring I was asked by a property management group to fix the stairwells in 5 story apartment building built in the 20's...the paint was falling off the walls and the plaster had turned to powder in several spots...when I removed the powdered plaster, I could see the exterior brick, and it was sweating to the inside at the mortar joints. Four years ago the building had been painted with a heavy oil based paint to solve their moisture problem... "SEaling" the walls......effectively destroying the walls by not letting the lime beneath the paint breath......again 99.9% of lime based plaster degradation occurs from someone wanting to seal the wall...or like in your case encapsulating the wall with wall paper. Chances are the paper will hold up for a little while, but with the cost of causing further damage to
the integrity of the plaster, I would opt for a nice latex paint.
Historic landmarks like The White House are painted with lime based paint. at least over their plaster walls.http://www.youtube.com/user/virginia...?feature=watch