Roundtower 3.5 Natural Hydraulic Lime, or Moderately Natural Hydraulic Lime, is a strong mortar option with all the flexibility that comes with natural lime. For historic buildings, that flexibility makes all the difference.
Natural lime has higher permeability in general, and allows for moisture to enter and escape freely – unlike Portland mortar, which locks in moisture at setting and cracks over time. In addition, using the same mortar as the original builders preserves the integrity without sacrificing quality.
Used for repointing and exterior work, 3.5 NHL can withstand exposure to the elements without fail. Building settling and freezing and thawing conditions aren’t a problem for lime of this caliber.
The 3.5 no polymers or cements, and needs to be mixed with water before use. With a range of between 12% – 18% active hydraulic components, like clay, 3.5 NHL can be reworked 16 hours after mixing.
Read the installation guide below and feel free to contact us with questions or a custom quote for colors.