BILL NUMBER: SB 332 ENROLLED
BILL TEXT
PASSED THE ASSEMBLY AUGUST 20, 2001
PASSED THE SENATE MAY 7, 2001
AMENDED IN SENATE MARCH 27, 2001
INTRODUCED BY Senator Sher
FEBRUARY 20, 2001
An act to amend Sections 18944.30, 18944.31, 18944.33, 18944.35,
and 18944.40 of the Health and Safety Code, relating to building
standards.
LEGISLATIVE COUNSEL'S DIGEST
SB 332, Sher. Building standards: straw-bale structures.
Existing law, known as the State Building Standards Law, creates
the California Building Standards Commission and authorizes it to
review proposed building standards, adopt or reject these proposed
standards, and codify and publish the adopted standards in the
California Building Standards Code. Local agencies have the
responsibility for the enforcement of numerous provisions of the
California Building Standards Code.
The law declares the intent of the Legislature to adopt safety
guidelines for the construction of structures, including
single-family dwellings, that use baled rice straw, as defined, as a
loadbearing or nonloadbearing material. The guidelines do not become
operative within any city or county unless and until a specified
finding is made and the finding is filed with the Department of
Housing and Community Development.
This bill would revise the guidelines and would require them to
apply to the construction of all structures that use baled straw as a
loadbearing or nonloadbearing material within a city or county that
has adopted the guidelines in existing law prior to January 1, 2002.
It would provide that the guidelines proposed by this bill would not
become operative in any other city or county, unless and until the
legislative body of a city or county makes an express finding that
the guidelines apply within the city or county because of local
conditions and the city or county files a copy of the finding with
the department. Because the bill would impose new duties on local
enforcement agencies, the bill would constitute a state-mandated
local program.
(2) The California Constitution requires the state to reimburse
local agencies and school districts for certain costs mandated by the
state. Statutory provisions establish procedures for making that
reimbursement, including the creation of a State Mandates Claims Fund
to pay the costs of mandates that do not exceed $1,000,000 statewide
and other procedures for claims whose statewide costs exceed
$1,000,000.
This bill would provide that, if the Commission on State Mandates
determines that the bill contains costs mandated by the state,
reimbursement for those costs shall be made pursuant to these
statutory provisions.
THE PEOPLE OF THE STATE OF CALIFORNIA DO ENACT AS FOLLOWS:
SECTION 1. Section 18944.30 of the Health and Safety Code is
amended to read:
18944.30. The Legislature finds and declares all of the
following:
(a) There is an urgent need for low-cost, energy-efficient housing
in California.
(b) The cost of conventional lumber-framed housing has risen due
to a shortage of construction-grade lumber.
(c) Straw is an annually renewable source of cellulose that can
be used as an energy-efficient substitute for stud-framed wall
construction.
(d) The state has mandated that the burning of rice straw be
greatly reduced.
(e) As a result of the mandated burning reduction, growers are
experimenting with alternative straw management practices. Various
methods of straw incorporation into the soil are the most widely used
alternatives. The two most common methods are nonflood
incorporation and winter flood incorporation. Economically viable
off-farm uses for rice straw are not yet available.
(f) Winter flooding of rice fields encourages the natural
decomposition of rice straw and provides valuable waterfowl habitat.
According to the Central Valley Habitat Joint Venture component of
the North American Waterfowl Management Plan, in California's Central
Valley, over 400,000 acres of enhanced agricultural lands are needed
to restore the depleted migratory waterfowl populations of the
Pacific flyway. Flooded rice fields are a key and integral part of
the successful restoration of historic waterfowl and shorebird
populations.
(g) Winter flooding of rice fields provides significant waterfowl
habitat benefits and should be especially encouraged in areas where
there is minimal potential to impact salmon as a result of surface
water diversions.
(h) An economically viable market for rice straw bales could
result from the use of rice straw bales in housing construction.
(i) Practicing architects and engineers have determined that the
statutory guidelines established by Chapter 941 of the Statutes of
1995 contain specific requirements that they believe are either
unnecessary or detrimental. Some of the requirements are considered
costly and severely restrict the development of straw-bale housing.
(j) Statutory guidelines for the use of straw-bale housing would
significantly benefit energy conservation, natural resources,
low-cost housing, agriculture, and fisheries in California.
(k) Tests and experience with straw-bale construction demonstrate
that it is a strong, durable, and thermally superior building system
that deserves a larger role in modern construction.
SEC. 2. Section 18944.31 of the Health and Safety Code is amended
to read:
18944.31. (a) Notwithstanding any other provision of law, the
guidelines established by this chapter shall apply to the
construction of all structures that use baled straw as a loadbearing
or nonloadbearing material within any city or county that adopted the
guidelines established by Chapter 941 of the Statutes of 1995 prior
to January 1, 2002. This requirement shall not preclude the city or
county from making changes or modifications to the guidelines
pursuant to subdivision (b). Notwithstanding any other provision of
law, the guidelines established by this chapter shall not become
operative in a city or county that has not adopted the guidelines
prior to January 1, 2002, unless and until the legislative body of
the city or county makes an express finding that the application of
these guidelines within the city or county is reasonably necessary
because of local conditions and the city or county files a copy of
that finding with the department.
(b) A city or county may, by ordinance or regulation, make any
changes or modifications in the guidelines contained in this chapter
as it determines are reasonably necessary because of local
conditions, provided the city or county files a copy of the changes
or modifications and the express findings for the changes or
modifications with the department. No change or modification of that
type shall become effective or operative for any purpose until the
finding and the change or modification has been filed with the
department.
(c) Nothing in this chapter shall be construed as increasing or
decreasing the authority to approve or disapprove of alternative
construction methods pursuant to the State Housing Law, Part 1.5
(commencing with Section 17910) or the California Building Standards
Code, Title 24 of the California Code of Regulations.
SEC. 3. Section 18944.33 of the Health and Safety Code is amended
to read:
18944.33. For the purposes of this chapter, the following terms
are defined as follows:
(a) "Bales" means rectangular compressed blocks of straw, bound by
strings or wire.
(b) "Department" means the Department of Housing and Community
Development.
(c) "Flakes" means slabs of straw removed from an untied bale.
Flakes are used to fill small gaps between the ends of stacked bales.
(d) "Laid flat" refers to stacking bales so that the sides with
the largest cross-sectional area are horizontal and the longest
dimension of this area is parallel with the wall plane.
(e) "Laid on edge" refers to stacking bales so that the sides with
the largest cross-sectional area are vertical and the longest
dimension of this area is horizontal and parallel with the wall
plane.
(f) "Loadbearing" refers to plastered straw-bale walls that bear
the dead and live loads of the roof and any upper floor.
(g) "Nonloadbearing" refers to plastered straw-bale walls that
bear only their own weight, such as infill panels within some type of
post and beam structure.
(h) "Plaster" means lime, gypsum, lime cement, or cement plasters,
as defined by the California Building Code, or earthen plaster with
fiber reinforcing.
(i) "Straw" means the dry stems of cereal grains left after the
seed heads have been substantially removed.
SEC. 4. Section 18944.35 of the Health and Safety Code is amended
to read:
18944.35. (a) Bales shall be rectangular in shape.
(b) Bales used within a continuous wall shall be of consistent
height and width to ensure even distribution of loads within wall
systems.
(c) Bales shall be bound with ties of either polypropylene string
or baling wire. Bales with broken or loose ties shall not be used
unless the broken or loose ties are replaced with ties which restore
the original degree of compaction of the bale.
(d) The moisture content of bales, at the time of installation,
shall not exceed 20 percent of the total weight of the bale.
Moisture content of bales shall be determined through the use of a
suitable moisture meter, designed for use with baled rice straw or
hay, equipped with a probe of sufficient length to reach the center
of the bale, and used to determine the average moisture content of
five bales randomly selected from the bales to be used.
(e) Bales in loadbearing walls shall have a minimum calculated dry
density of 7.0 pounds per cubic foot. The calculated dry density
shall be determined after reducing the actual bale weight by the
weight of the moisture content.
(f) Where custom-made partial bales are used, they shall be of the
same density, same string or wire tension, and, where possible, use
the same number of ties as the standard size bales.
(g) Bales of various types of straw, including wheat, rice, rye,
barley, oats, and similar plants, shall be acceptable if they meet
the minimum requirements of this chapter for density, shape, moisture
content, and ties.
SEC. 5. Section 18944.40 of the Health and Safety Code is amended
to read:
18944.40. (a) Straw-bale walls, when covered on both sides with
at least one inch of plaster shall be deemed to have a fire resistive
rating of at least one hour.
(b) Minimum bale wall thickness shall be 13 inches.
(c) Buildings with loadbearing bale walls shall not exceed one
story in height without substantiating calculations and design by a
civil engineer or architect licensed by the state, and the bale
portion of the loadbearing walls shall not exceed a height-to-width
ratio of 5.6:1 (for example, the maximum height for a wall that is 23
inches thick would be 10 feet 8 inches).
(d) The ratio of unsupported wall length to thickness, for
loadbearing walls, shall not exceed 15.7:1 (for example, for a wall
that is 23 inches thick, the maximum unsupported length allowed is 30
feet).
(e) The allowable vertical load (live and dead load) on top of
loadbearing bale walls plastered with cement or lime cement plaster
on both sides shall not exceed 800 pounds per linear foot, and the
resultant load shall act at the center of the wall. Straw-bale
structures shall be designed to withstand all vertical and horizontal
loads, and the resulting overturning and base shear, as specified in
the latest edition of the California Building Code. Straw-bale
walls plastered with cement or lime cement plaster on both sides
shall be considered capable of resisting in-plane lateral forces from
wind or earthquake of 360 pounds per linear foot.
(f) Foundations shall be designed in accordance with the
California Building Code to accommodate the load created by the bale
wall plus superimposed live and dead loads. Supports for bale walls
shall extend to an elevation of at least six inches above adjacent
ground at all points, and at least one inch above floor surfaces.
(g) (1) Bale walls shall be anchored to supports to resist lateral
forces. This may be accomplished with one-half inch reinforcing
bars embedded in the foundation and penetrating the bales by at least
12 inches, located along the center line of the bale wall, spaced
not more than two feet apart. Other methods as determined by the
engineer or architect may also be used.
(2) Nonbale walls abutting bale walls shall be attached by means
of one or more of the following methods or by means of an acceptable
equivalent:
(A) Wooden dowels of 5/8 inch minimum diameter and of sufficient
length to provide 12 inches of penetration into the bale, driven
through holes bored in the abutting wall stud, and spaced to provide
one dowel connection per bale.
(B) Pointed wooden stakes, a minimum of 12 inches in length and
11/2 inches by 31/2 inches at the exposed end, fully driven into each
course of bales, as anchorage points.
(C) Bolted or threaded rod connection of the abutting wall,
through the bale wall, to a steel nut and steel or plywood plate
washer, a minimum of 6 inches square and a minimum thickness of 3/16
of an inch for steel and 1/2 inch for plywood, in a minimum of three
locations. A continuous 2x woodplate may serve as the washer.
(3) (A) Bale walls and roof bearing assemblies shall be anchored
to the foundation where necessary by means of other methods which are
adequate to resist uplift forces resulting from the design wind
load. There shall be a minimum of two points of anchorage per wall,
spaced not more than 6 feet apart, with one located within 36 inches
of each end of each wall.
(B) With loadbearing bale walls, the dead load of the roof and
ceiling systems will produce vertical compression of the walls.
Regardless of the anchoring system used to attach the roof bearing
assembly to the foundation, prior to installation of wall finish
materials, the nuts, straps, or cables shall be retightened to
compensate for this compression.
(h) A continuous moisture break shall be used between the top of
the foundation and the bottom of the bale wall to prevent moisture
from migrating through the foundation so as to come into contact with
the bottom course of bales. This break shall consist of 6 mil
polyethylene sheeting or any type of waterproof coating or membrane
suitable for below-grade foundation wall dampproofing. There shall
also be a drainage plane between the straw and top of the foundation,
such as a one-inch layer of pea gravel.
(i) (1) For nonloadbearing walls, bales may be laid either flat or
on edge. Bales in loadbearing bale walls shall be laid flat and be
stacked in a running bond, where possible, with each bale overlapping
the two bales beneath it. Overlaps shall be a minimum of 12 inches.
Gaps between the ends of bales which are less than 6 inches in
width may be filled by an untied flake inserted snugly into the gap.
(2) Bale wall assemblies shall be held securely together by rebar
pins driven through bale centers, paired rebar pins tied through the
wall, mesh reinforcing tied uniformly through the wall, or equivalent
methods as approved by the engineer or architect.
(3) Only full-length bales shall be used at corners of loadbearing
bale walls.
(4) Bales in loadbearing walls shall be secured across all corners
of every course. Those walls may be secured with staples of #3 or
larger rebar formed into a "U" shape, a minimum of 18 inches long
with two 6-inch legs, driven with one leg into the top of each
abutting corner bale, or any equivalent method.
(j) (1) All loadbearing bale walls shall have a roof bearing
assembly at the top of the walls to provide a clear load path from
the roof structure to the bale wall. The roof bearing assembly shall
be continuous along the tops of loadbearing bale walls.
(2) The floor or roof bearing assembly shall be designed to
transmit dead, live, and lateral loads from the supported floor or
roof to the bale walls and wall plaster.
(3) The connection of floor or roof framing members to the floor
or roof plate shall comply with the appropriate sections of the
California Building Code.
(k) All openings in loadbearing bale walls shall be a minimum of
one full bale length from any outside corner, unless exceptions are
approved by an engineer or architect licensed by the state to
practice. Wall or roof load present above any opening shall be
carried, or transferred, to the bales below by one of the following:
(1) A frame, such as a structural window or door frame.
(2) A lintel, such as an angle iron cradle, wooden beam, or wooden
box beam. Lintels shall be at least twice as long as the opening is
wide and extend a minimum of 24 inches beyond either side of the
opening. Lintels shall be centered over openings.
(3) A floor or roof bearing assembly designed to act as a rigid
beam over the opening.
(l) (1) All weather-exposed bale walls shall be protected from
water damage. However, no membrane barriers may be used on the bale
walls, except as specified in this section, in order to allow natural
transpiration of moisture from the bales and to secure a structural
bond between plaster and straw.
(2) Bale walls shall have special moisture protection provided at
all horizontal surfaces exposed to the weather. This moisture
protection shall be installed in a manner that will prevent water
from entering the wall system.
(m) (1) Interior and exterior surfaces of bale walls shall be
protected from mechanical damage, flame, animals, and prolonged
exposure to water. Bale walls adjacent to bath and shower enclosures
shall be protected by a moisture barrier.
(2) Cement or lime cement plaster shall be reinforced with 17
gauge galvanized woven wire stucco netting or an equivalent, as
approved by the building official. The reinforcement shall be
secured by attachment to or through the wall. If the wall is
loadbearing, or to be used as an in-plane shear-resisting element in
seismic zone 4, the reinforcement shall:
(A) Be tied through the wall with at least 16 gauge galvanized
wire at a maximum spacing of 24 inches horizontally and 16 inches
vertically, as required to remain in place during plastering.
(B) Be fastened to all surrounding wood framework and openings
with at least 16 gauge galvanized staples at no more than 4 inches on
center.
(C) Be lapped at all seams at least six inches.
(3) Where bales abut other materials, the cementitious plaster or
stucco shall be reinforced with galvanized expanded metal lath, or an
acceptable equivalent, extending a minimum of 6 inches onto the
bales.
(4) Earthen and lime-based plasters may be applied directly onto
bale walls without reinforcement, except where applied over materials
other than straw.
(n) (1) All wiring within or on bale walls shall meet all
applicable provisions of the California Electrical Code. Type "NM"
or "UF" cable may be used, or wiring may be run in metallic or
nonmetallic conduit systems.
(2) Electrical boxes shall be securely attached to wooden stakes
driven a minimum of 12 inches into the bales, or an acceptable
equivalent.
(o) Water or gas pipes within bale walls shall be encased in a
continuous pipe sleeve to prevent leakage within the wall. Where
pipes are mounted on bale walls, they shall be isolated from the
bales by a moisture barrier.
(p) Bales shall be protected from rain and other moisture
infiltration at all times until protected by the roof of the
structure.
SEC. 6. Notwithstanding Section 17610 of the Government Code, if
the Commission on State Mandates determines that this act contains
costs mandated by the state, reimbursement to local agencies and
school districts for those costs shall be made pursuant to Part 7
(commencing with Section 17500) of Division 4 of Title 2 of the
Government Code. If the statewide cost of the claim for
reimbursement does not exceed one million dollars ($1,000,000),
reimbursement shall be made from the State Mandates Claims Fund.