Aidomes vs Hempcrete

40′ Assembled Aidome in Trinidad: when finished w’ local materials is three bedroom/two bath.

Ai has had inquires asking if we can make our dome kits using hempcrete. Although hempcrete is a lightweight material (that many people confuse with concrete), it is not a structural component, it is an insulating component. It cannot hold the weight needed to support even a traditional building on its own. As opposed to our panels which provide structural support, prefinished concrete exterior, insulation, and interior ½” drywall finish for the shell of the home.

The following is a statement from American Lime Technology:

“It is not used as a structural element, only as insulating infill between the frame members though it does tend to reduce racking (The movement of structural elements out of level or plumb by forces such as stress, wind, or material shrinkage or expansion.). All loads are carried by internal framing.”

Once all the panels of the kit are assembled, the Ai dome is self-supporting. There is no wood to interrupt our insulation. And no internal framing is needed to support our dome.

Users of Hemp Crete need to apply to the hempcrete wall an exterior coating -plus a finish to the coating, interior ½” drywall and an insulated roof. “The material is finished on the outside with a hard render coating about 20mm (1”) thick to protect it with a final colored topcoat finish added.” (needs to be a lime-based coating, which is expensive and hard to find). To achieve an R-Value of 23 (Ai’s insulation is R-28) you would need 12″ thick walls. So, a home built with hempcrete would have 13″ walls (after coating and prior to drywall), have a frame (wood or steel) structure that would interrupt your insulation. And you still need to install a roof and insulate the roofline of the home.

Ai’s dome kits come with 80% of your exterior (3/4” prefinished concrete reinforced with galvanized steel mesh and fibers), 95% of your insulation (entryways and window/doors openings only, will need to be insulated), as well as ½” special Georgia Pacific DensArmor drywall that meets international building code. Once erected, you need only prime the concrete and then paint the exterior concrete with elastomeric house paint.

Although hempcrete is durable, and can withstand high winds (174 mph), you would still have a roof that could blow off and needs replacement. Our domes have no roofline to blow off or needs replacement, and can withstand 225 mph winds!

Hempcrete needs to be imported, it is not produced in the United States (due to federal regulations). In addition, the estimate to build a home (not a commercial structure) with hempcrete was over $225 per square foot (in 2012) not including finishing the interior (i.e. cabinetry, plumbing, electric, appliances etc.). That is over $350,000 even before you start working on the inside of your home. A 1,532-sq. ft. hempcrete home erected in 2014 cost $65,000 for the hempcrete alone, this did not include the cost of framing, interior drywall, or exterior coating.

In comparison, a 40’ Aidome building kit that is comparable in size has an estimated cost of $44,879 and includes insulation, drywall (for shell) and our durable galvanized steel mesh concrete exterior (which you paint with standard elastomeric house paint). The cost to build one of our structures is comparable to a traditional home. As an example the estimate construct a dome with the same square footage in Central Florida would be $200,000.