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Plaster condensation

2500 Views 8 Replies 7 Participants Last post by  drywallfinisher
Okay, I bought an old 1850s pioneer home in Ohio that is 18" thick of brick. Some of the exterior walls have windows and I am not building them out to drywall and insulate...
I was told by my Amish uncle that they condensate and I am concerned because I want to wallpaper. Does it condensate that bad if I keep the heat regulated? What kind of water sealant paint or barrier could I use?
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The windows may condensate but the walls??
In all my years I ave never seen walls form condensation as you explained.
I've seen it and every time it was becuse of to high a humity in the home caused from things such as a gas unvented fire place, not having a bathroom vent fan, a range hood that was not venting outside, poor roof venting, no vaper barrier on the ground in the crawl space.
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 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 :thumbsup: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.
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I will not argue with drywall finishers theory but wallpaper has been applied to plaster walls for hundreds of years with no problems.
If warm moist air impinges on a cold wall and the temperature of the wall is below dew point for the amount of moisture present, you will have condensation. It is a law of physics. It won't matter if you have wallpaper, lime plaster or 3 coats of high gloss epoxy. You either have to reduce the amount of moisture or warm the wall to above dew point to elimninate the condensation. It's that simple.
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Guys don't neglect the fact that these walls are 18" thick brick. I have worked on a couple of these houses when I lived in Ohio. One had walls that were 24" thick. They would set up and actually make the brick on site. Enough history, I think the problem may be not enough air movement. What kink of HVAC is being used?
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"If you can’t stop the damage function, at least concentrate it at a location where you can deal with and within a material you can replace."
Good stuff, thanks
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