Crete
Crete: Mix of Portland Cement with either Hemp, Paper, Foam or Pumice
Building with Crete, what are the methods and benefits. Learn more about the different crete’s. Each crete are created different and have different attributes and qualities.
The Crete’s described here are Hempcrete, Hempcrete Block, Papercrete, Papercrete Block, Aircrete/Aircrete Block and Pumicecrete. Also learn a little about the pros and cons with each product.
Hempcrete or hemplime is a mixture of hemp, lime and sand. Like any great product it has been given many names. There are several benefits with Hempcrete including is easier to work with than traditional lime mixes and it acts as an insulator and moisture regulator. It is a lightweight insulating material and has thermal mass which makes it ideal in most climates. Hempcrete walls are also fireproof, transmit humidity, and have excellent acoustic performance.
In France they have used Hempcrete since the early 1990s and have now become popular in Canada.
It is normally used as infill (non-bearing walls) however recently blocks have been developed that can be used as load-bearing walls. This is why that Hempcrete is traditionally used is similar to Rammed Earth using forms that are filled with Hempcrete on the construction site.
In the United States, it might be a challenge to get permits for a traditional Hempcrete building.
Recently, the Hempcrete industry have developed Hempcrete Blocks that are prefabricated and brought to the construction site. Many of these blocks are made so that they can be used as load-bearing walls and are build similar to a masonry construction method.
Pros
- Green
- Regenerable
- Insulating
- Thermal Mass
- Can be shaped
Cons
- Must Use Forms
- Labor Intensive
- Permits Could Be a Challenge in the US
- Supply Issues in the US
Hempcrete or hemplime is a mixture of hemp, lime and sand. Like any great product it has been given many names. Hempcrete is easier to work with than traditional lime mixes and acts as an insulator and moisture regulator. It is a lightweight insulating material, and it has thermal mass which makes it ideal in most climates. Hempcrete walls are also fireproof, transmit humidity, and have excellent acoustic performance.
In France they have used Hempcrete since the early 1990s and have now become popular in Canada.
Recently blocks have been developed that can be used as load-bearing walls. These blocks are prefabricated and brought to the construction site. They are stacked and build similar to a masonry building.
In the United States it should be easier to get permits on a Hempcrete block building than a traditional Hempcrete building.
Pros
- Green
- Regenerable
- Insulated
- Thermal Mass
- Easy to Build
- Stackable
Cons
- Supply must be transported to work site
- Supply is limited
- Supply issues in the US
- Permit in the US could be a challenge
Papercrete is make with re-pulped paper fiber and Portland Cement or Clay and/or other soil added. It was first patented in 1928, due to it being easy to make it had no commercial value furthermore paper was expensive in the early 1900s. Many kinds of paper can be used including old newspaper, junk mail, magazines and books. The paper is re-pulped in water and then mixed with Portland cement. There are different mixes from small hand mixers to the big tow-mixers. Once it is mixed it can then either be poured into forms and dried in the sun or the mixture can be used as a plaster.
Papercrete is a very moldable material and can be designed to many different shapes. It is even possible to build domed ceiling/roofs. The surface of the papercrete can be plastered with a lime plaster or other breathable plaster form.
It was then rediscovered again in the 1980. One of the people that is a big advocate for papercrete is Barry Fuller of Arizona. Barry Fuller introduced papercrete to the Arizona State University and have worked together with them to get papercrete standardized. Over the years he and several others have worked on creating a machine to make the block/brick so they can be more standardized.
There is still no ICC code for this building material so it will depend on the permitting government whether it can be approved. If permitted, it would likely be as an infill build. Due to this lack of an official code most Papercrete houses are build outside of city limited and in areas where building codes are more lax building code , or no building code at all, where it is possible to build with no restrictions.
Pros
- Cheap building materials
- Simple to build
- Insulated
- Soundproof
- Creative shapes and buildings
Cons
- Permitting Challenges
- Infill build
- Difficulty finding enough paper
Papercrete Block is made with re-pulped paper fiber and Portland Cement or Clay and/or other soil added and then compressed into blocks. More information about papercrete can be found above.
Barry Fuller and Zach Radon are both created a machine that produce a compressed papercrete block. With this technology it would be possible to get a more standardized product to get permitted with a code in the ICC. Zach Radon founded Mason Greenstar in Mason, Texas have been the first to produce and sell a commercially viable papercrete block. He calls his block :Blox Building System”. It is currently the only mass-produced commercial papercrete block on the market. Over the years he has built several buildings using his papercrete blocks “Blox Building System”.
Pros
- Upcycling
- Simple to build
- Insulated
- Soundproof
Cons
- Limited Supply
- Difficulty with Permitting
- Transport of supply to building site
Aircrete is a simple mix of concrete and foam bubbles. It is basically regular Portland cement mixed in with a dense soap bubble mass. This combination hardens into a highly dense material with impressive compressive strength. The addition of iron rebar adds additional structural integrity. In Aircrete the use of traditional aggregate is replaced with air bubbles which are produced with a dence soap foam bubble mix.
GaiaDome is one company that specializes in making aircrete domes. They say that “aircrete is a lightweight cementitious material that contains stable air cells uniformly distributed throughout the mixture. Aircrete utilizes a stable air cell rather than a traditional aggregate. It is also called cellular concrete, foam concrete, lightweight concrete, aerated concrete, etc.”
There is no one formular for aircrete, as the exact formular depends on how the aircrete will be used. The higher proportion of foam/air bubble used will create less compressive strength however higher insulation value. It is possible to add traditional aggregate to create more structural strength.
The mix is poured into forms of either blocks or panels and then set to dry. Once dried the forms are removed and further drying for a time. Once dried the building blocks/panels are ready to be ensembled.
Pros
- Simple to mix
- Very flexible
- Insulation Value
Cons
- Use of Portland Cement
- Lack of Supply
- No Clear Formular
- Difficult with permitting
Pumice Crete is a mix made of pumice aggregate, Portland cement and water. It has great structural strength and insulation in that one mix. Walls are normally on site in a thickness of 14″ or greater with no need of added insulation or other structural components needed. Once the walls poured, they are then plastered on both the exterior and interior. This building material is durable, fireproof and good soundproofing. It is possible to be creative with the formwork and create unique features. Pumice Crete is easy to heat and cool to fit the temperature required.
It can be found in many places in the US and has been used for thousands of years in the building industry.
Pros
- Lightweight
- Fireproof
- Insulation Quality
- Pumice has no reaction to steel or concrete
- Soundproof
Cons
- Finding supplier
- Built formwork
- Permit Issues