Jackie, Lime wash and lime plasters when placed over any surface will manage moisture naturally..ie cement/concrete holds water til it can dry out, but with washes or plasters the lime is 'hydrophilic'--water loving, it can hold a great deal, then begin to evaporate it quickly away after.
this is why it is popular on strawbale walls...coated as they are in concrete plaster, when water seeps in the bales will just rot, and you can't tell , until trouble..sometime fire caused by thermal buildup from gases.
Lime acts not like a raincoat--not allowing water in, but more like a good wool sweater, soaks up moisture..but KEEPS it in itself, not allowing to just pass thru to the wall, and if any does (severe rains) it allows the moisture a route out, unlike a 'raincoat'
make sense?
I have done clay-paper-sawdust plasters over crappy old particle board walls, then a nice natural lime+sand+paper plaster....once it cures no paint is needed, it prevents mold and bugs, I put this plaster up over my north facing cold bathroom walls, tiny room with a shower, just to see if it would fail...after 6 years of daily use there is not one speck of mold or growth as in normal bathrooms.
The lime has hardened back to limestone..and will NOT burn now**, and an occasional simple wipe down,(mostly for dust or cobwebs) not a scrub keeps it clean.can be lime washed every few years for freshening up, or to add a color tint if you don't want all white. and it feels great to the touch, people respond to this.
The recipe I used ( for inside only..will wear out sooner outdoors when exposed) is a Chinese recipe I discovered in a book detailing many many earth and lime home build styles..amazing what they did in rural China with no tools or materials other than clay.
another plus of this plaster- with shredded paper in it-- is you can create an ancient, old world look, or very smooth, or add more sand and get a Mexican stucco look...
** ONE main advantage of using lime over papercrete is it provides similar fire-burn barrier of gypsum drywall..for your safety code requires a 1.5 hour burn thru time, if you are NOT installing conventional gypboard you need something, for your own protection, even if no codes are involved/inspection, etc.
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Chinese recipe for Paper Lime plaster interior use By WEIGHT-1 part (lb.) chopped/shredded paper-office paper – or newspaper insulation to 10 parts (lb.) soft lime putty (type N or S hydrated lime soaked in water 48 hours) Mix well in large bucket or bin with tight lid. Seal lid. Let mellow 2-4 weeks, stir in 1/2-1 parts sharp sand to make more trowelable. Mix with paint stem/paddle blade to make creamy.. Spread on wall by hand or trowel. Sculpt and dry. feather edges thin at stop points. Can be limewashed; embed tiles while soft. Adding extra sand gives a stronger, more old world plaster/mortar look; for outdoor use eliminate paper or coat with sealer, or waterglass.
Note from Charmaine: Successfully applied to new and old DRYWALL, particle board on my work studio & bathroom walls.
Lime & Clay Resource Guide: http://www.papercrete.com/limeclaycdguide.html
National Lime Assoc www.lime.org/
Pargeting-decorative lime www.kettlenet.co.uk/
US Parks Building articles: www.cr.nps.gov/hps/tps/briefs/presbhom.htm Lime plaster on Straw Bales: http://solarhaven.org/Construction4Lime.htm Tadelakt lime plaster- www.naturalpaint.com.au/
Building Conservation-Lime articles: www.buildingconservation.com/
article on rice and lime building:
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Charmaine Charmaine Taylor/Publishing & Elk River Press
PO Box 375 Cutten CA 95534
www.papercrete.com Robert Heinlein (1907-1988) "There is no worse tyranny than to force a man to pay for what he does not want merely because you think it would be good for him." (Obamacare)
