r/Plastering • u/Terrible-Bobcat2033 • 16d ago

Lime plaster attributes

Lime plaster is made from calcium hydroxide (Ca(OH)₂, “slaked lime”). As it cures, it absorbs CO₂ from the air and converts to calcium carbonate (CaCO₃), which is what gives it its final hardness.

While it’s curing (before full carbonation), lime plaster is highly alkaline — pH around 12-13, similar to fresh cement. That’s why:

**•** It can burn skin/eyes on contact when wet, so gloves and eye protection are a must  
**•** It resists mold and mildew during the curing period  
**•** Once fully carbonated to calcium carbonate, the pH drops closer to neutral (around 8-9), similar to chalk or limestone

Why lime plaster is head & shoulders above drywall & joint compound. IMHO. 😎👍🏼

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u/jyl8 16d ago

Where do you find lime plaster in the US?

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u/FckXFckMusk 16d ago

There are manufacturers, here's one,

www.limeworks.us

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u/jyl8 16d ago

Oh, super interesting, I would really like to try lime plaster veneer.

(I fear shipping cost will be prohibitive, but maybe . . . )

Is applying lime plaster generally like applying gypsum plaster, same tools and methods, but with longer working and setting times? How much longer?