Edge-Plus™

plan view diagram of the Edge-Plus straw-bale wall

Edge-Plus is our next generation straw-bale building system, engineered exclusively for The Naturally Passive House. In this system, straw bales are stacked on-edge in a running bond in the same way as with our Baling-on-the-Edge system. The major difference, however, is that stud framing members replace external pins as a means to anchor the bales. The cavities between studs can then be filled with cellulose, another natural material, which boosts the insulation value of the entire wall assembly sufficiently to meet Passive House standards. Our Edge-Plus system offers the following additional advantages when compared to more conventional straw-bale building systems (above and beyond those of our Baling-on-the-Edge system):

  1. greater familiarity — stud framing is a common residential building practice, and therefore more familiar to contractors and building officials
  2. no notching around posts — stud walls replace posts as structural support, and bales are stacked completely inside of the inner face of the exterior stud walls
  3. less moisture issue potential — because stud walls separate the bales from the exterior building face, the chances of the bales encountering bulk moisture are significantly reduced
  4. simplified electrical installation — wiring is run conventionally in the exterior stud walls rather than between courses of bales
  5. no re-tying of bales, or making half bales
  6. no stuffing the gaps between bales after stacking

The last two items above (#'s 5 & 6) are a radical departure from other straw-bale building systems — no proponents of any other system can make these claims. Because of #'s 5 & 6, the resulting wall is actually faster to construct and yields a more uniform surface for plastering. Edge-Plus is totally unique!

Our Edge-Plus system also offers the following advantages when compared to Lath-Plus, our other Naturally Passive House building system:

  1. no inner stud wall — double walls are unnecessary as straw bales take the place of both the additional cellulose insulation and inner stud wall with straw/clay stuffing
  2. faster construction — bale work is faster than straw/clay work

Once the straw bales have been stacked, the interior face of the straw-bale wall is coated with a thick layer of earth plaster. A thin coat of breathable finish plaster is then applied over the rough coat of earth plaster — lime, earth, and gypsum are all appropriate finish plasters. We have also developed extensive construction details for the Edge-Plus system, including foundation and roof interfaces, door and window framing, electrical and plumbing integration, cabinetry and trim attachment, etc. Please contact us for specifics regarding your Naturally Passive House project.