Previously, we outlined whether hempcrete was stronger than concrete. We also looked into the disadvantages of hempcrete. The latter piece showed us the limitations of this building material. However, today, we’re going to investigate what you can use hempcrete for when building.
Hempcrete’s Uses in Construction
Hempcrete undoubtedly has limitations. The main one is the lack of compression strength, which means it is unsuitable for load-bearing. Nonetheless, hempcrete has several advantages to consider. Hempcrete:
- Is lightweight and easy to transport, not to mention non-toxic.
- Increases in strength over time
- Maintains a steady temperature
- Doesn’t shrink.
- Enables moisture to evaporate, thus reducing the risk of mold.
- Isn’t attractive to termites.
- Sequesters approximately 307 kilograms of carbon dioxide per cubic meter. In contrast, concrete and its binding cement account for about 8% of all CO2 emissions generated by humans.
Let’s see how you can use hempcrete when building a house. What you’ll find is that this material is a useful insulating tool.
1 – Roofs & Floors
You can use hempcrete with other materials to develop a layer of insulation in roofs and floors. Builders can also use it to create infill panels. These are non-load bearing panels found between the floors of a building’s main structural frame. Traditionally, companies use infill panels made from masonry or concrete. However, hempcrete is potentially a viable alternative.
You can also include it when retrofitting infill panels. This process tends to take place when restoring traditional and historic buildings. Use hempcrete to replace or repair the infill panels on old timber frame properties.
2 – Walls
To reiterate, you shouldn’t use hempcrete for building foundations. However, you can install it in a cavity within the wall. Alternatively, you can add it as an extra layer in the build-up. You can utilize hempcrete to form the walls and insulation in a single piece. Then you rely on materials such as concrete or steel for the structural frame.
3 – Outdoor Furniture
This is a potentially innovative means of using hempcrete. Remember, it absorbs and stores a significant amount of CO2 from the atmosphere. You can use it in outdoor benches, seats, or tables to help the environment. Hempcrete is also waterproof and extremely durable.
Hempcrete as an Insulator
Several organizations are beginning to trademark their hempcrete-creating processes. BCB Tradical is a French company doing just that. The brand has written about casting its hempcrete as an insulating lining for walls on its official website.
According to BCB, you can use its hempcrete as an insulating layer directly on the substrate. There is no need to include any air space or joints. This ensures continuity between materials. Benefits of BCB’s hempcrete as an insulator include eliminating the ‘cold wall’ effect and absorbing temperature variations. The latter is crucial as hempcrete tends to suffer when exposed to significant variations in temperature.
BCB points out that hempcrete remains free from bacterial attacks. It is also useful at keeping pests such as termites and rodents at bay. The company offers varying thicknesses ranging from 5cm to 20cm depending on your preferences and needs.
How to Use Hempcrete in Construction
As hempcrete isn’t a load-bearing material, using it involves casting it to timbers or another material. Companies typically implement one of the following three methods of casting hempcrete.
1 – Spraying
This is a time-saving process. The company evenly sprays plywood sheets with hemp lime mix to attach the mixture to the wood. The next step involves combining the binder and hemp slurry at the sprayer’s nozzle. As the hempcrete solution is emitted from the nozzle at high pressure, it sticks rigidly to the surface.
2 – Tamping
This method involves using plywood sheets as a mold. A worker must tamp the hemp mix with a wooden stave or their hands. It is necessary to tamp the mixture to prevent large air voids from forming. Eliminating these voids ensures that the hempcrete has excellent insulation properties. It is important to create a balanced pressure while tamping to prevent the formation of the air voids.
3 – Blocks
The use of hempcrete blocks in buildings is becoming more popular. In this case, you need to use a load-bearing framework. Most companies choose timber for this purpose. Place the hempcrete blocks on the wood, and make the necessary changes before installing the wall plate.
Manufacturers construct hempcrete blocks by pressing, aging, and packing hemp-lime.
Is It Worth Persevering with Hempcrete as a Building Material?
As long as you’re realistic about what hempcrete can do, it is worth considering for certain purposes. Research published in the Journal of Cleaner Production in 2019 reviewed hempcrete’s properties for green building applications. Overall, the study authors found that it met the standards of most building applications. In some instances, it outperformed certain materials commonly used, particularly when used for insulation.
The most significant advantages of hempcrete include its capacity to reduce construction waste.
Among the most significant advantages of hempcrete is its capacity to reduce construction waste. One estimate suggests that concrete comprises 50% of debris generated by the construction and demolition of buildings. The United States Environmental Protection Agency said that the construction industry created approximately 23 million tons of concrete debris in 2015.
Hempcrete has potential as a replacement for materials used in non-structural elements of walls. Companies can also use it instead of drywall and plaster. These two materials account for around 8% of all building construction debris.
Final Thoughts on What You Can Use Hempcrete For
Builders are starting to see the benefits of hempcrete. It has been used to build or renovate in several European countries and Australia. At present, several obstacles are preventing more widespread use. For one, the lack of availability is an issue. There aren’t enough hemp processing plants that can process the plant into a form usable as hempcrete. However, with industrial hemp now legal to grow in the United States, that may change.
There is room for hempcrete in the construction industry. However, it will take some time before it is more widely used.