Learn about Lime Plaster

Lime plaster is made by combining lime, sand, and water. Instead of setting chemically like modern gypsum plaster, lime plaster cures over time by absorbing carbon and carbonates in the air around it.

When buying lime plaster, look for products made and graded for your intended interior or exterior use.

Construction lime is categorized as:

• Natural hydraulic lime<
• on-hydraulic lime

While there are differences, the most distinct variation is how they set.

Hydraulic limestone sets faster by a hydrolysis process, has greater compressive strength, and is often used for a building's exterior. Hydraulic lime is available in 3 grades, NHL 2 and NHL 3.5, and NHL 5. Higher NHL represents a faster setting and higher compressive strength. Non-hydraulic lime takes longer to set (or cure) and does so by absorbing carbon dioxide from the air around it.

Non-hydraulic lime is often used indoors and is more flexible.</p>

The amount of embodied energy to produce lime plaster is one quarter that of Portland cement. While cement is scrutinized for carbon footprint, non-hydraulic lime captures carbon dioxide during the curing process.