FAQ

Please review the questions and answers before contacting us. This page will be updated often!

We hope that the information will be of value to you as you consider hempcrete as an excellent building choice. We receive many simple- sounding questions, but some of the answers will get technical and there are lot of variable potential answers. You may also get different opinions between laboratory research and from people who work in the field, actually building or living, in hempcrete houses. Always take any information with a grain of salt, just don’t put the salt in the hempcrete….

We will only consult if you have a diagramed outline of your building! Even if you have done it yourself on graph paper, we need a working diagram to reference. Drafting services are available upon request.

For the record, currently the only book (and a good one) on hemp building is Steve Allin of Ireland: www.hempbuilding.com. Many of the basic ideas are in that book. Our book and DVD will be another year or so in coming out, and will contain more detailed building advice. 

 There are important details that we do differently to cut the cost of the hemp walls/floor and make a better product for the North American demographic. For example; using only  timber frame and a different mix of hemp-crete ingredients than is done in Europe.

What people are really often asking is “How expensive is it to build the hempcrete part of the house and how much risk is there?”. In our experience, we have found that a single family residential house can be built for close to the same price as a quality custom-built stick frame house in your area. Much will depend on the level of finishing that you want and what area of your country that you live in; climate considerations etc. Also there is a question of; are you building with a financial plan in mind; i.e. a rental suite or small home business/farm. This may help defray the ultimate building costs. Not usually considered in the cost of a house is the operations and maintenance of the new house. The "word" in the building industry is that (with luck) you get 2 free years of no maintenance and then expect yearly maintenance costs. Consider that a small building may be more expensive per square foot as you still need all of the other things for a house; permitting, plans, kitchen, septic systems, foundation/roof, heating, bath being the most expensive parts. Please speak with your building professional when pricing and budgeting. Rather than using hard quotes, work with your builder to formulate estimates with best-case/ worst case scenarios.
We offer an initial 30 minute consultation via telephone. You do need basic plans drawn up and a pre-consultation questionnaire will soon be available. In the meantime think about: How much machinery (i.e. front end loader) you have and how much free/low cost labour. Are you going to subcontract or build yourself? Also to consider the cost of the hemp shipment; how thick do you want your walls ? What type of climate do you live in? What kind of structure (timber, dimensional, wood, metal)? What kind of foundation, etc.?
This is a complicated question and one that is still being investigated. R-Values measure thermal resistance, or the ability of a material to resist movement of heat through it’s structure. The higher the R-value, the more the material resists the movement of heat. The R-value is a static number that does not calculate thermal mass performance. Work has recently been done on thermal inertia values of hempcrete. When this factor is taken into account it helps to explain the incredible comfort that families report when they stay in a hempcrete house. Thermal mass is a concept in building design which describes how the mass of the building provides "inertia" against temperature fluctuations; basically the ability of the material to absorb and radiate heat or cool. In the winter, in-floor heating can provide efficient warming of the house and in a hot summer, the mass of floors and walls will keep the house cool. Hemp walls, because they “breathe”, unlike concrete, also have a moisture regulating quality. There have also been many tests with adobe buildings in the USA and it has been found that the total performance of the building is higher than the perceived static R-value. Hemp may have similar thermal performance that is still being investigated. In a nutshell, those living in hemp-concrete houses from the Viggiano Mountain in Italy to damp conditions on the West Coast of Canada, have found them more comfortable to live in and less costly to heat/cool than stick/plastic/gypsum houses.
Basic hemp recipes can be found online; usually in a 20-25% binder mix of lime/cement /sand/ clay to 75-80% by volume of hemp. So you can mix it yourself! There are many variations of using hempcrete as a wall-mass or insulation, or a base for breathable tile.
There are projects in France now 40 years old and getting stronger all of the time. Also there are some very pretty 2000 year old Roman aqueducts!
Due to high demand for visits , we are currently only accepting consulting clients, or potential clients who have an interest in building with hemp.
Industrial hemp is NOT the marijuana plant and has been “legal” all over the world for thousands of years, and was in fact a required crop in the USA during wartime for its many textile and fabric uses. There is a theory that hemp was too much of a competitor for American cotton and timber interests and, because of it’s distant relationship to the marijuana plant, was lumped together.
Because of the stigma attached to marijuana, we don't associate industrial hemp and what we do with anything to do with marijuana. There is a clear distinction between marijuana and industrial hemp. The confusion between the two species is hurting the industrial hemp industry. However, once the difference is understood then it makes the industrial hemp more acceptable .
Not to our knowledge; the cost of setup and machinery is high, and with current emerging demand for hemp building it is difficult to justify the cost.
Yes, please see Partners/links page. No retail at this point that we know of.
There are a number of great books available now and there are a number industrial hemp organizations; The Canadian Hemp Trade Association in Canada http://www.hemptrade.ca and The National Hemp Association in Washington DC https://nationalhempassociation.org
This is a consulting question! We are happy to help out small owner builders with details like this, but there will be a fee. We will NOT work without written plans to refer to. Please have some kind of diagram in drawn up BEFORE the consultation!
If you are pouring, as opposed to spraying, the hemp mix, you need to tamp. A stick or spade works well and some people like a sledge hammer. We tamp until the fibres are lightly compacted, but not jammed together with all of the liquid forced out.
In our experience , outdoor, and in-contact-with-the-earth applications of hempcrete may not work well. Hemp is very resilient but does need time to dry out between soakings and unprotected slab applications may not work well in the long term. There are recipes and applications for below-ground hempcrete, but your own application would have to be reviewed by a qualified builder or engineer. For most practical purposes and inexperienced builders we suggest keeping hempcrete where it can be allowed to breathe freely.
Amazing! How many times during the storms of winter has one member of the family said “I love our little house!”. It is warm in the winter, cool in the summer, amazingly quiet and cozy- just what a house should be!
We have completed a few old house renovations and we feel that hempcrete is the best way to allow a house to breathe. There have been may issues with older house renovations where the modern building code requires layer upon layer of plastic to “seal” the house. This approach , in our view is totally erroneous from both environmental (heavy reliance on petrochemicals) and practical reasons; many of these new, multi-layered-in-plastic buildings we predict will show significant damage in the next few decades. Assuming that, with technology, we can make something impervious to air and moisture movement is typical human hubris. Perhaps it can be achieved, but the real questions are for how ling and at what cost? Both now and in the future? It is far better to build with a mass- wall system with natural materials and achieve better results.