Virginia Beach Architects Visit ‘Mare Cannabum’ to learn about Hempcrete Installation

This week we paid a visit to the site of the ‘Mare Cannabum’ hemp home in Virginia Beach, Virginia. We began to design this house in 2012 with our wonderful clients, the Meehans, and architect Gerri West.

GC Jim Sykes, Tim Callahan, Site Supervisor Pat O'Rork, Architect Gerri West and client Michael Meehan stand on the 'Big Coastal' porch and talk to a group of local architects.
GC Jim Sykes, Tim Callahan, Site Supervisor Pat O’Rork, Architect Gerri West and client Michael Meehan stand on the ‘Big Coastal’ porch and talk to a group of local architects.

It is clear looking at this unique home and the interest it is accumulating, that our efforts and careful planning are paying off! Around 20 people, mostly architects, came out for a tour and reception at the site on Wednesday. They had great questions about the product and its installation. We hope that some of them will be inspired to try it for themselves.

As of this week, about half of the hempcrete has been installed of the 3000 or so cubic feet required to fill the exterior walls. Jim Sykes Construction has been installing the hempcrete in approximately 8″ lifts, removing the forms as each course is stable.

Hempcrete being installed by Jim Sykes Construction. Here the hemp-lime mix has been poured into the form and is ready to be tamped.
Hempcrete being installed by Jim Sykes Construction. Here the hemp-lime mix has been poured into the form and is ready to be tamped.

 

Hempcrete that is being tamped down into the form.
Hempcrete that is being tamped down into the form.

After the walls have been formed, the hempcrete will need to cure and dry for the next 30-45 days, before receiving lime plaster on both sides.

Back porch of the 'Big Coastal' hempstead. The forms have been removed and the hempcrete is beginning to cure.
Back porch of the ‘Big Coastal’ hempstead. The forms have been removed and the hempcrete is beginning to cure.

It was exciting to once again see all those bales of hemp shiv stacked up!

Hemp bales stacked inside the house to stay dry.
Hemp bales stacked inside the house to stay dry.

It seems that the crew is enjoying working with the new material, and are getting pretty efficient at it! On the day that we visited, they set their new record of 24 bales installed, compared to their previous record of 18. The hemp is mixed with the binder in small batches using a mortar mixer. Because hempcrete is not heavy, once mixed, it is simply carried in a bucket to the location in the house.

Hemp shiv sits in buckets waiting to be mixed with binder.
Hemp shiv sits in buckets waiting to be mixed with binder. The man in this photo wears a mask, because the drying qualities of lime dust can be very irritating to the lungs!
Tim Callahan and Pat O'Rork talk about the project.
Tim Callahan and Pat O’Rork talk about the project.

 

One clever method devised by the guys installing the hempcrete was to use PVC pipe to create forms for the window and door heads and jambs. The hempcrete is packed in there and then the form is removed and reused.

PVC as window forms.
PVC as window forms.

 

Door with transom and beveled jambs.
Door with transom and beveled jambs.
Clouseup of the end result of the PVC forms.
Clouseup of the end result of the PVC forms.

When there was an arch top window or door to be formed for the hempcrete, they scored the PVC before putting it up.

Scored PVC pipe that was used to form hempcrete on an arched window head.
Scored PVC pipe that was used to form hempcrete on an arched window head.

Result: a smooth arch top window. The result was great! A mesh lath will be installed in the first layer of lime plaster to prevent any of the thinner areas from cracking.

Arch top window formed with PVC and hempcrete.
Arch top window formed with PVC and hempcrete.

 

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Jennifer Bennett is an architectural drafter, graphic designer and photographer, working for Alembic Studio in Asheville, North Carolina.