30 EARTHBAG BUILDING
2.28: Using sandbox bags as a substitute for rigid
for easy removal, face one row of dry-fill sand bags out, tie or pin shut with a nail
box forms.
wedge arch form on top of level board
use chicken wire cradles to delineate between sandbox bags and regular earthbags
install additional sand bags lengthwise
Velcro Plates “Velcro� plate into tamped earthbag with 3� galvanized nails
2.29: Strip anchors provide an attachment for doorjambs and certain types of windows.
doorjamb 2.30: Most doorjambs
bolted to
can be bolted to an adequate attachment surface that is provided by an average of four strip anchors spaced every three to four rows.
strip anchor
Doorjambs, shelf attachments, electrical boxes, intersecting stud frame walls, lintels, rafters, and extended eaves for domes, all need to attach to something that anchors them into an earthbag wall. Velcro plates are simply a flat wooden plate from onehalf to one-inch (1.25-2.5 cm) in thickness, about twelve to sixteen inches (30-40 cm) long, cut to the approximate width of the wall and nailed into the bags. A strip anchor (a term used in adobe construction) allows for the later attachment of doorjambs after the forms are removed. A strip anchor is a length of two-by-four or two-by-six attached to a Velcro plate. It is then placed with the two-inch (5 cm) side flush against the box form and Velcroed (nailed) into the rammed earth bag below with two-and-one-half (6.25 cm) to three-inch (7.5 cm) long galvanized nails (Fig. 2.29). The bag work continues over the top of the strip anchors, incorporating them into the wall system during construction (Fig. 2.30). Windows can also be attached to strip anchors or can be shimmed and set into the walls with plaster alone. A type of modified strip anchor is used for the placement of electrical boxes, lintels for rectilinear window and door frames, cabinetry, shelving, and anything that needs to be securely attached to the finished walls. A Velcro plate is used by itself to help distribute the weight of an eave or rafter across multiple bags.