Words and Meaning
Many terms, words, and acronyms are used in The Last Straw to describe construction methods,
materials, tools, and processes. This section of the Resource Guide is intended
to help define those unfamiliar to some. We hope you will add to this list, and
correct us if our definition is slightly wrong!
Aliz, a
clay slip applied to an earth-plastered wall, almost like paint is used on
other surfaces, to seal and beautify the surface; after it has become soiled or
damaged, another coat may easily be applied to renew its fresh look.
Traditionally, aliz was applied with a sheepskin in a very thin layer.
Bale is a
large bundle of straw bound with cord or wire while Bail is the temporary release of a prisoner in exchange for
security.
Cast Earth uses gypsum (plaster of paris) and set-retarding additives with soils to
form walls with greater tensile strength than adobe and rammed earth.
Cob,
moistened earth containing suitable clay and sand content, mixed with straw;
formed into stiff loaves of movable size; piled onto a wall and blended with
previous layers. Produces a monolithic, load-bearing mud wall. Used to fill
voids in straw-bale walls prior to applying exterior/interior coatings.
Comealong/come-a-long, a tool, similar to a winch, that gives one person the
ability to pull or lift objects that are very heavy; also used to stretch wire.
Cord of
wood, the amount of wood in a stack of
48-inch logs (or cut logs equaling 48 inches) that is 4 feet high and 8 feet
wide. A half-cord or face-cord or rick describes a stack of the same dimensions
as a cord, except the logs are 24 inches long. Many fireplaces and woodstoves
cannot accommodate this length so are cut to 20 inches to fit. Ð Mother
Earth News, October/November 2004
Cordwood (or stackwall) uses split or whole sections of
softwood (without bark) as masonry units laid in two cement mortar tracks (one
on the outside, one on the inside) filled with sawdust and lime or cob
(cobwood).
Durawall, a
brand name for a welded metal wire product used in reinforcing concrete,
sometimes laid between bale courses and tied into the support structure and
bales to add lateral strength to the wall.
Earthbags
(also called Superadobe) are filled with mostened clay-bearing soil,
laid in courses, tamped solid and held together by long-point barbed wire to
prevent slippage. Used for domes, walls, fills and foundations.
Ecocomposites. The combination of two or more materials, typically with fibers that
remain identifiable combined with a matrix that together are stronger than
either material alone.
Fines,
finely crushed or powdered material (as ore, rock, stone); very small particles
in a mixture of various sizes.
Forb (something
you do not want to have in your bales). A broad-leaved herb other than a grass,
especially one growing in a field, prairie, or meadow.
Gabions are
used for thermal mass and in foundation systems. Containers of wire filed with
stone, sometimes supported by upright posts when stacked on the vertical.
Gringo Grip,
a product consisting of heavy metal wire and a grasping mechanism wrapped
around materials to hold them together securely. Can be used to secure/support
hundreds of pounds of weight; works on any thickness straw-bale wall as
tie-down. Simple, inexpensive through-the-bale anchor for fastening cabinets,
interior wall sections, electrical boxes, fixtures, and pipe/conduit to
straw-bale walls.
Gypsum, the
raw material (minerals alabaster, satin spar, selenite) used for gypsum
plasters, wallboard/drywall; gypsum plaster, unlike cement, expands on setting,
does not crack unless there are faults in the backing; must never be mixed with
Portland cement.
Hay is not
straw. Hay is grass, clover, alfalfa mown and dried for fodder.
HVAC,
heating, ventilation, air conditioning.
Insolation
is the rate of solar radiation per unit of horizontal surface.
LSL, Laminated Strand Lumber, used as load-bearing header material.
MDF (medium
density fiberboard) is a board made of wood fiber and glue. MDF is often used
for moldings, casing, finish trim and cabinets. MDF will not split or crack
easily.
Nicho/Niche,
a recess in a wall, especially for a statue; creates a small shelf space used
for display, and sometimes used as a ÒtruthÓ window in bale walls.
Papercrete
(also called padobe or fidobe) is waste paper mixed with water, sand, cement
(or clay for padobe and fidobe).
Parging, coating with plaster; especially applying ornamental or waterproofing plaster.
Pex, a
generic name for a polybutelene or
polyethylene tubing commonly used for radiant floor heating and increasingly
for domestic water supplies. Comes in long rolls like garden hose. Less
expensive than copper, more costly than PVC; no glues, fewer fittings. Various
brand names including Wirsbo.
Pise (Pneumatically
Impacted Stabilized Earth) (pise de terre means rammed earth) uses formwork
to contain a stabilized earth mixture poured at high pressure from gunite
machines.
Plinth, a
block or slab forming the base of a column.
PSL, Parallel Strand Lumber, made from long, thin strands of wood structurally
bonded together in a patented microwave process to make large cross section
columns and beams.
PVC,
polyvinyl chloride plastic piping; shown to outgas harmful gases, and not used
for water supply piping in a healthy home.
Pozzolan, a
siliceous volcanic ash used to produce hydraulic cement; any of various
artificially produced substances resembling pozzuolana ash.
Purlin,
Timber used to support roofing sheets. Usually fixed on top of rafters; a
horizontal structural member spanning between beams or trusses to support a
roof deck; a horizontal member attached perpendicular to the truss top chord
for support of the roofing (i.e., corrugated roofing or plywood and shingles).
Rubble trench foundations eliminate frost heave by the use of
loose stone or rubble to minimize the use of concrete and improve drainage,
considered
more environmentally friendly because cement manufacturing requires the use of
enormous amounts of energy. To construct a rubble trench foundation, a trench
is dug down below the frost line and then filled with drainage tile and loose
stone. A concrete cap is poured to provide ground clearance.
Scoria, a light-weight,
dark-colored, glassy, pyroclastic igneous rock containing many vesicles
(bubblelike cavities). Foamlike scoria, in which the bubbles are very thin
shells of solidified basaltic magma, occurs as a product of explosive eruptions
(as on Hawaii) and as frothy crusts on some pahoehoe (smooth- or
billowy-surfaced) lavas. Other scoria, sometimes called volcanic cinder,
resembles clinkers, or cinders from a coal furnace.
Spalling, the spider-web kind of cracking often associated with
freezing damage or water expansion damage.
Stem Wall, anchors the foundation to the ground, usually constructed
of cinder block reinforced with steel and concrete, typically three courses
high, and poured at the same time as the slab in one continuous pour, marrying
the slab to the foundation and the walls to the slab and stem wall.
Strapping,
metal bands used to tie down bale walls in the process of compressing the
walls.
Straw is
the dry cut stalks of grain (wheat, oats, rye, rice, etc.) used as a material
for bedding, thatching, and straw-bale construction.
Straw/clay or Light Straw-clay (from the German Leichtlehm), lightweight
mixture of straw and clay slurry which coats each strand of straw; the wet
material is compacted into a formwork (removed the same day) resulting in a
precise wall with enough texture to accept mud plaster without further
preparation or lathing. Often used as an ÒoutsulatingÓ wall around a
timber-frame structure; can also be used an as infill material between deep
structural members.
Toe-ups, a
combination of wood and fill (e.g., pea gravel, rigid insulation, blocks)
attached to the slab or floor deck to protect the bales from water that might
pool on the floor during construction or a plumbing or drainage problem.
Toed-up Foundation. The stem wall is elevated above the floor slab
approximately 4 inches. (See Stem Wall)
Truss, a type of framework, usually comprising
straight struts and ties, designed to be stiff. This is achieved by the
inclusion of a sufficient number of triangles. Some or all of the joints may be
fixed rather than pinned, but the main contribution to the stiffness is
provided by the triangulation.
Truth Window,
an exposed portion of a bale wall allowing a view of the bale so that people
know Òin truthÓ there is baled material (straw, grasses, hay) in the wall.
Truth windows are a creative addition to any straw-bale building, framed with a
variety of materials such as small windows, doors, metalwork, and more.
Urbanite,
broken concrete used in foundations, walls and floors. Reuse keeps it out of
landfills; it is a free (usually) and strong building material.
Wattle-and-Daub,
a substrate for
earthen materials made from small branches or twigs woven into a lattice.