|
In the U S Green Building
Council’s LEED for Homes
program there are 8 areas of
Accountability (Innovation and
Design Process, Location,
Sustainable Sites, Water
Efficiency, Indoor
Environmental Quality,
Materials and Resources,
Energy and Atmosphere, and
Awareness and Education).
In last month’s column, we
discussed two of the 5
potential credits that can be
attained in the Sustainable
Sites category. In this column
we will discuss the remaining
three (Shading of Hardscapes,
Surface Water Management, and
Non-Toxic Pest Control).
Shading of Hardscapes:
The intent is to reduce local
heat island effects. There are
no mandatory measures for this
credit. The optional measure
is to design and install trees
and shrubs to shade at least
50% of sidewalks, patios, and
driveways within 50 feet of
the house (at 5 years’ growth)
OR install light colored,
highly reflective materials
for at least 50% of the site’s
non-roof impervious surfaces.
The shading of hardscapes
around the home will reduce
irrigation needs as well as
temper the home’s outdoor
environment. Also, locate
trees, fences, shrubbery or
other plantings to capture or
deflect seasonal breezes as
appropriate. The local heat
island effect can be minimized
by providing shade over paved
surfaces. This will enable the
homeowner to better utilize
the outdoors, even on hotter
days. As is typical of our
terrain, the home footprint
area on our lot consisted
primarily of Ashe Juniper
(cedar). We chose to eliminate
most of the cedars around the
house footprint. Once
construction was completed, we
planted a 3-inch diameter
Chinquapin Oak tree to shade
the carport area. Other
landscaping choices were
native and/or drought tolerant
plants and shrubs, such as
desert willows, Mexican
redbud, various salvias,
skullcap, and germander. This
fall we will be planting
additional trees: a big tooth
maple, a lacey oak and a Texas
ash.
Surface Water Management:
The intent is to minimize
erosion and run-off from the
site. The mandatory measure is
to install permeable material
for at least 65% of the
undeveloped portion of the
site. The project is exempt
from this measure if the lot
is less than or equal to ¼
acre. The optional measures
are a) Install permeable
paving material (e.g. pervious
pavement or grid pavers) for
exposed walkways, patios,
playgrounds, recreation
courts, aprons, and driveways;
b) Design and install
permanent erosion control
measures. These could be
installing permanent storm
water control (i.e. vegetated
swales, onsite rain garden,
etc.); reducing long term
run-off effects through the
use of terracing and retaining
walls and planting one tree or
four 5-gallon shrubs per 500
sq ft of disturbed
construction area, or four
large, 5 gallon shrubs (four
5-gallon shrubs are equivalent
to one tree). Erosion
represents the loss of a
valuable resource from the
home site — topsoil — that can
overload storm sewers, and may
cause stream clouding and
siltation (with potential harm
to wildlife). Permeable
surfaces also encourage
recharging local aquifers and
may reduce irrigation needs.
Even though an asphalt
driveway would reduce the dust
and not diminish scarring the
terrain, we purposely chose
screened river rock as the
driveway material for its
pervious nature. The paving
industry has developed
pervious asphalt and concrete;
however, I could not find any
contractors in the area that
used these pervious materials.
We also used crushed granite
on the walkways, again for
its pervious nature and lack
of dust.
Non-Toxic Pest Control:
The intent is to avoid the
use of poisons for insect and
disease control. There are
only optional measures for
this requirement. A) In areas
with termite infestation,
treat all cellulosic material
(e.g. wood framing) with a
borate product to a minimum of
3 feet above the foundation OR
place sand or diatomaceous
earth or a steel mesh barrier
termite control system OR use
non-cellulosic (i.e. not wood
or straw) wall structure. B)
In areas with termite
infestation, use solid
concrete foundation walls OR
masonry wall with top course
of solid block bond beam or
concrete filled block.
C) Keep all wood used at least
12” above soil (code requires
8”. points. D) Protect exposed
foundation insulation with
moisture-resistant, pest-proof
cover (e.g. fiber cement
board, galvanized insect
screen). E) Install
rodent and corrosion proof
screens (e.g. copper or
stainless steel mesh) on all
openings that cannot be
caulked or sealed. F) Separate
any wood-to-concrete
connections (e.g. at posts,
deck supports, stair
stringers) with metal or
plastic fasteners / dividers
OR have no wood-to-concrete
connections. G) Install
landscaping so that all parts
of mature plants will be at
least 24” from the house.
Adopting turf limits and
native plantings can help to
reduce the need for other
toxic chemical such as
fertilizers, pesticides,
herbicides, etc. Keeping
plants away from the house is
also advisable to avoid
irrigating close to the house
and thereby minimize the risk
of moisture leaking into the
home’s foundation.
Further resources for the
reader:
IPM Practitioners
Association – This site places emphasis on
urban, non-agricultural
applications.
Bio-Integral Resource
Center – Part of what makes the LEED
for Homes program important
and work for all of the
industry and environment is
that the compliance of these
homes with LEED criteria must
be verified by a third party
(other than the builder).
Verification activities
include documentation, review,
field inspections, and
performance testing.
Common Sense
Pest Control, William Olkowski,
Shiela Dar, Helga Olkowski,
Taunton Press, 1991 |
