Hempcrete insulation for office trailer

Hello everyone I'm interested in getting a 27' office trailer from ebay and then insulating with hempcrete. Does anyone know if a 27' structure will be accepted as a "mobile home"?

Although the gentleman in the land planning department said 27' is ok I wonder if he knows that it's an office trailer and not a "single wide". I just don't want to run into problems later after I purchase the structure. Any insight into land use and permits would be appreciated.

Cant help much with the permitting/zoning as that would be highly specific to your area. As for the hempcrete insulation plans.. are you sure about that? I am of the opinion that hempcrete has crummy Rvalue.

The building codes are generally lax around the area. I realized after I originally posted that some office trailers are 60' long so it makes no real difference about the length. What matters is that the structure has a solid steel frame so it can be tied down to deal with bad weather.

I like Hempcrete because of the thermal mass for temperature regulation, acoustic insulation and excellent control of humidity (preventing mold). It's also easy to work with, light-weight, and lasts centuries. When incorporated into a building, if it is torn down, the product can be recycled into further hemp wall construction.

Does anyone know if an office trailer is considered a mobile "home"/ manufactured "home" and whether or not a person can obtain permits for an office trailer to become a vacation cabin?

Btw Brian there's an amazing Hempcrete company right in Ashville, NC. Please watch the short video. They explain the benefits better than I do. If builders just make the walls thicker the R-Value is just fine.

I toured two of their projects and worked on the SIP roof of one of them. Iam not convinced Hempcrete is the wrong way to go but I think the lack of Rvalue and is a concern. There is also the issue of air infiltration/exfiltration though the hempcrete. The project I helped with failed to meet the passivehaus airtightness requirements and I believe the engineer in charge seemed to think the hempcrete was the problem.

I havent seen a third party evaluation of hempcrete R value but my guess would be it has about the same Rvalue per inch as wood (R1 per inch). This makes it more of a thermal mass than insulation in my opinion. Sure you could meet the poorest performance allowed by law with a 13" thick hempcrete wall but I suspect a 13" thick wall filled with fluffy insulation would perform much better for preventing energy use and thermal losses. A 13" thick wall filled with real insulation would be about R46. This R value talk assumes the walls do not have air flowing through them which may not be the case with hempcrete?

Again, not really trying to bash hempcrete, just think you need to be careful when specifying it for insulation or thermal performance.

Brian Knight,
The R-value of hempcrete is around R2/inch, and sometimes higher, but there is also the thermal mass and heat capacity which leads to a 12 hour or more phase change of temps from outside to inside and vice-versa. The hempcrete builders in England say that their homes will stay at a pretty steady 65F whether hot or cold outside with a 12" thick wall, once the roof, windows and doors are in.
As for air transpiration, the right hempcrete will be dense enough to slow that down, and with s good render on at least one side, it acts as an air barrier and traps the pockets of air inside. It works very well when done with the right details.

It is difficult (or impossible?) to compare a rocket mass heater to a traditional heating unit using BTU. The way it heats is so different, that it is not a good comparison. In the same way, while the R-Value is higher for Hempcrete than Brian thinks, I'm not sure that R-Value is the best measurement for this kind of building material. In order to be looking at R-Value and how air-tight the house is, you have to make some assumptions about what makes a comfortable house. Does a house need to be air sealed (to the extent modern houses are) in order to keep its occupants comfortable? I don't think so. Also, can it keep them comfortable for long term? There are many modern houses with mold problems from being TOO airtight.

If you get outside of "normal", then it's hard to compare strictly on "normal" measurements.

As a home efficiency professional kinda early stages on the path....I've noticed that stucco homes seem to generally be more comfy than can be expected with the small amount of insulation often extant in their exterior walls.

Some of the properties of hempcrete that go beyond simple r-value have probably been in use in housing materials for millenia, similarly to how stucco and adobe have been helping make comfortable shelter since deep into what is often called "prehistory", in spite of often profound feats of record keeping.

With a decent cap of insulated roof to compensate for stack effect, 12" inch thick hempcrete walls would offer more than excellent insulation (within the broad range of expected
r-values),  and options for siding or exterior treatment would only add to insular qualities and structure longevity.