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American Hydraulic Lime


The Made-in-USA alternative to imported Natural Hydraulic Lime (NHL) products.

American Hydraulic Lime is for those who want the performance of natural hydraulic lime (NHL) without having to import foreign products, which can be costly and impractical.

Naturally long-lasting and beautiful, American Hydraulic Lime can be used for making breathable lime mortar, lime plaster or lime render, stucco, limewash paint, and more! Compatible with natural building methods including hempcrete, adobe and strawbale construction.

Best described as a pozzolanic hydraulic lime, our blended American Hydraulic Lime is totally free of Portland cement and designed to comply with ASTM C1707: Pozzolanic Hydraulic Lime for Structural Purposes.

Our American Hydraulic Lime also meets or exceeds standards outlined in the IRC Residential Code for Hempcrete/Hemp-Lime Construction and the Commercial Spec Guide for Hempcrete.

Packaged in 50 lb., multi-wall paper bag with stitched closure and easy opening. Can be shipped by the bag or pallet. Contact us for bulk orders!

Example mix ratio: 1 part lime to 2 – 3 parts clean sand

1 x 50 lb. bag American Hydraulic Lime to 200 – 300 lbs. sand will yield 3 – 4.5 cubic feet of mortar/plaster.

SKU: AHL50 Categories: , ,


American Hydraulic Lime by Hemp and Block is formulated to achieve a low carbon footprint in its production and use. The less energy and resources required to produce this material, the more sustainable and energy efficient it becomes.

For example, in the production of hydrated lime, it’s fired at much lower temperatures than what is required for making Portland cement clinker. Therefore using more hydrated lime in construction and less Portland cement improves sustainability.

Next, consider the additional minerals or ash that can be added to hydrated lime to increase its strength and hydraulic effect. Fly ash, blast furnace slag, metal dust from ironworks, calcined (fired) clays, and volcanic based materials. Each of these has its own footprint (energy inputs required for production). Some may have inherent pollutants or exposure to elements that you’d prefer not to touch.

We favor using volcanic based materials when possible, as they are naturally calcined (activated) and do not require additional firing. These incredible materials were activated by the original volcanic explosion hundreds of thousands (or millions) of years ago!

This is a key part of why the Hemp and Block American Hydraulic Lime is truly a “low footprint” building material. It will maximize the performance and sustainability of your hempcrete or masonry projects, help qualify for LEED points/Green Energy certifications and more!

A special history

Our American Hydraulic Lime is based in part on the most magnificent, long-standing structures of human history. Notably, the Roman Pantheon, still standing proud after nearly 2,000 years. The Pantheon is a marvel of engineering, as the worlds largest unreinforced (e.g. no “steel rebar”) concrete dome, at 142 feet in diameter. And the foundation of Roman concrete, was the combination of volcanic ash pozzolan and powdered, calcined (fired) limestone.

The Roman Pantheon is a magnificent example of “masonry done right.”


Additionally, this pozzolanic hydraulic lime is compatible with historic masonry and conservation work. It’s “breathable” and flexible unlike mortars and plasters made with Portland cement, which reduces vapor permeability and are excessively hard, brittle and damage softer stonework/masonry.

Shipping options

The shopping cart is setup with FedEx Ground delivery for smaller orders, such as 1-5 bags. For larger orders, contact us for a free freight quote.

Weight 50 lbs


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