by Mike Guertin with Clayton
DeKorne
In today's slow housing market, the one bright spot is decidedly
green. Everywhere you look, green building is grabbing the
attention of otherwise cautious home buyers.
But all this attention raises the potential for "green-washing"
— the efforts of overzealous marketers to label anything and
everything "green." Building a green home is certainly much more
than slapping down bamboo flooring. And the media hasn't helped the
matter by parsing "green" into a bunch of unrelated "plug and play"
solutions. Selectively focusing on one feature while ignoring
others or intentionally misleading buyers about the green
credentials of a product or process only threatens to diminish the
concept of green building as a whole.
One of the reasons many builders and the general public don't
understand green building is because it encompasses so much. Green
building touches just about everything we do when we build a
structure. It wasn't until I had to teach a green building course
for high school and junior college construction career programs
that I began to wrap my head around what it means to be green and
how to explain it in concrete terms.
Soak your brain with the LEED for Homes (www.usgbc.org/leed/homes),
NAHB Model Green Home Building Guidelines (www.nahb.org/publication_details.aspx?publicationID=1994),
the SBIC Green Building Guidelines (www.sbicouncil.org/store/gbg.php)
and the ICC - NAHB National Green Building Standard (www.nahbrc.org/technical/standards/greenbuilding.aspx),
and you'll begin to find common threads between the different
programs. You may realize, as I did, that the houses you build are
already pretty "green" just by the nature of building along the
coast. Coastal regulations and climate conditions typically force
us to build to a much higher green threshold than might be required
in other regions.
To conceptualize the big picture of what green building
entails, think of a tree with nine main branches. All are important
and interrelated, but some — namely energy and water
efficiency — should be considered higher priorities and take
a more prominent position in the overall green plan for a
project.
Energy first. Energy improvements sit at the
top of all green building priority lists for good reason: Energy
consumption represents an ongoing expenditure of resources. In all
coastal climates, focus attention on air sealing measures at
critical framing connections. One example is the band-joist area on
this Florida home (left), which has been sealed with spray foam to
stop air and provide optimal insulation. Attic bypasses, such as
the holes created by routing wiring through an attic (right), are
critical but often overlooked energy drains.
The important thing is to understand green building on two levels:
the big picture and the more fine-grained details of
implementation. You'll communicate with clients wearing your "big
picture" hat. To provide a better understanding of this big
picture, I break down green building into nine different branches
of a tree (previous page). Not every branch is weighted the same,
but none can be ignored. A perusal of the outline provided here
will provide a quick check on how close you're already coming to
building green and detail what practices you might need to reach
the goal.
Eventually, you'll have to steep yourself in the practical side of
pulling the pieces together on site, as well, but that will take
more than one magazine article.
Most coastal homes I build or remodel have a design professional on
board. If they are involved in green building, then my job is
simplified. If not, I "green engineer" the project, focusing first
on the following:
Water-managed details. Coastal contractors
understand the importance of managing water and how to keep
buildings dry. If you haven't already, develop a standard set of
details for flashings, window and door installation, siding, and
roofing that ensure your buildings will keep water out. (For more
information on good coastal water management practice, see "Best
Practice Wall Shingles," March/April 2007, and "Weather Barriers
for Coastal Conditions," January/February 2008;
www.coastalcontractor.net.)
Locally appropriate. Design features and
structural details that suit coastal construction in your area,
wind zone, and exposure. This isn't necessarily about aesthetics
but rather about roof pitches, overhangs, exposures, glazing area,
and structural load paths. If you get these right, you're well on
your way to a durable home that uses less energy.
Building orientation. Clients want to
maximize their view, of course, but we can tweak the design to take
advantage of prevailing coastal wind patterns for natural cooling,
to increase or decrease solar gain, and to improve natural
daylighting (see "Designing with the Sun in Mind," Fall
2005).
Footprint. While builders are usually
beholden to the wishes of our customer's desires, we can steer them
to build smaller. Smaller houses require fewer materials to build
and tend to use less energy. The net effect is a clear prescription
for conserving resources.
Energy
Efficiency
As a result of the ongoing use of resources inherent in the energy
use of any building, energy efficiency also comes at the top
of any green building priority list. The EPA/DOE Energy Star Home
program serves as a basis for the energy efficiency component of
many green building programs. Even though coastal environments are
tempered by ocean water (cooler in summer and warmer in winter)
compared with inland climates, they're still punishing when you
factor in the wind.
Durable details. Coastal contractors are no
strangers to rain-screen details that rely on drainage mats (as
shown) or battens, and a well-detailed water-resistive barrier, to
manage wind-driven rain. For exteriors on green homes, durability
and resis-
tance to water damage and mold takes precedence over any specific
material choice.
Building envelope — namely,
insulation and air sealing measures. I think air sealing is by far
the biggest issue for coastal contractors. Even a small constant
breeze on a building can drive conditioned interior air through
leaks. Special attention needs to be made to both window and door
installation to reduce loses. Other critical areas are at building
element connections (floor to foundation, wall to floor, roof to
wall) and penetrations in walls and ceilings (see "Details:
Airtight Framing," January/February 2006 and "Air Leaks: Hidden
Moisture Movers," July/August 2007).
Window and door selection. Coastal homes
usually have greater glazing area than inland homes. Choosing
higher-efficiency (both lower U-factor and lower SHGC) windows and
doors will have a greater impact on the energy performance of a
coastal home (see "Selecting Windows for Coastal Homes,"
March/April 2006). Interior shades are often overlooked from an
energy-efficiency standpoint. They help building performance by
reducing the heat gain of the summer sun and heat loss on a winter
night. These are usually left to the clients after a builder closes
out a project; I recommend coastal builders include this step as
part of their scope of work.
High-performance windows. Reduce cooling loads
by choosing windows that resist both radiant and conductive heat
flow. Look for the NFRC label found on all windows. The two
critical numbers are the U-factor, which measures heat flow, and
the solar heat gain coefficient (SHGC), which measures the
percentage of radiant heat energy that will pass through the
window. The lower these ratings are the better. For optimal
performance in all climates, both numbers should be below
0.35.
HVAC design and equipment. Heating and cooling loads
can be different when you're building an ocean-side house compared
with one just five miles inland. The HVAC equipment can often be
downsized because peak summer and winter loads are less —
this reduces the cost and complexity to install and reduces the
operational cost both in money and environmental impact.
Water Efficiency
Most coastal building environments have limited fresh water, and
potable water is a limited resource. Plumbing codes and government
regulations have driven us to green practices already with
low-flow/low-consumption fixtures inside the home. More than half
the water delivered to the average home is used for irrigation, so
looking at ways to reduce water use outside so the homes you build
or remodel will have less impact on local water supply is the first
course of action.
Landscaping. Avoid the need for
irrigation, but when necessary, use drip systems rather than
sprinkler systems.
Rainwater collection. Underground tanks
or simple rain barrels can store roof runoff for outside irrigation
needs as well as indoor nonpotable purposes such as toilets.
Collection and filtration systems are available for potable water
use.
Think twice about graywater reuse. While some green
proponents tout graywater reuse, coastal areas tend to be
environmentally sensitive. Graywater reuse systems may not be
permitted or wise for coastal zones.
Reduce water consumption. Increasingly, water
efficiency is climbing to the top of the green priorities list for
coastal homes. Low-flow fixtures are a must indoors, but don't
forget the landscaping. A landscape that relies on native plant
species will not only use much less water than a traditional lawn
but will also better withstand salt spray and poor coastal soil
conditions.
Construction Best
Practices
You're probably already incorporating "best practices" in every
aspect of your coastal projects. Best practices make for durable
low-maintenance (green) buildings.
Roofing, siding, windows, and doors. Coastal
buildings experience more wind-driven rain on a regular basis than
interior buildings. Detailing the exterior to resist water
penetration is critical for long-term durability.
Insulation and air sealing. To achieve the best
performance from insulation, it must be installed perfectly and the
building must be air sealed. Coastal buildings are exposed to
higher wind exposures than inland buildings, so air sealing has a
bigger overall impact to energy perfor-mance. Seal all penetrations
between inside and outside. Pay particular attention to air leaks
from the conditioned space to the attic space.
Renewable Energy Sources
Solar and wind resources can be tapped along shorelines, but with
some, maintenance may be an issue.
Photovoltaics. Knowing the true day of sunlight for
the microclimate you build in is important. Many coastal areas
(particularly in the Northeast) often experience more fog, haze,
and clouds that would reduce the performance of photovoltaic
panels. Airborne salt can deposit a film on collectors and reduce
their effectiveness. While photovoltaics may be the first thing on
clients' minds, they may not always be the best choice for all
coastal climates. Systems should be located for easy access to
clean, and owners need understand the seasonal energy production
limits due to clouds.
Solar hot water. Vacuum-tube systems are ideal for
cloudy coastal areas. These systems can produce hot water even on
cloudy days and will provide more bang for the buck than
photovoltaic systems. They will suffer from salt film on the tubes,
so someone will have to have easy access for cleaning (and be
willing to do it).
Wind. Residential-scale wind generators
are a slam-dunk for coastal buildings. Consistent breezes —
no matter from what direction — will spin the blades on
modern generators. Many states are incorporating laws that
supersede local zoning and private development restrictions that
would otherwise prohibit wind generators, though in many locales,
this remains an issue that must be investigated.
Geothermal. Coastal building sites often have high
water tables, and this is good thing when you're thinking of
geothermal. Deep well or field/trench-type exchange systems perform
better when they are in the water rather than dry soil.
Material Selection
Materials are often the first thing people think of when they think
"green," and it's where you'll find the most controversy. The
material arena is where you and your clients will find the most
greenwashing and become the most confused.
Green Spec. To cut through the bias and
confusion, consult Green Building Products (BuildingGreen, LLC and
New Society Publishers, www.buildinggreen.com) — a
compendium of some 1,600 green products derived from the online
Green Spec Directory
(www.buildinggreen.com/menus/).
Durability/reduced maintenance. Materials that last a
long time in service are preferable to ones that deteriorate. Most
coastal builders I know already opt for durable materials —
especially on building exteriors — because they understand
how punishing the coastal climate can be.
Lot Planning and Site Preparation
Many coastal building requirements mandate best practices for lot
usage and site impact already, so you may not need to change your
current practices to go green here.
Minimize site impact. Only clear and dig
where you have to. Coastal building sites are often environmentally
sensitive. Keep the natural geography and retain native plants to
minimize the effect of natural disasters and speed recovery (see
"Wetlands Done Right," January/February 2007). Minimal site impact
practices are often economical as well.
Erosion control during construction.
Common requirement on most coastal sites, you can improve erosion
control just by minimizing site impact to begin with. Wrap up
sitework activities as soon as possible and implement the
replanting plan to reduce the need for mechanical control systems
(see the discussion on low-impact development, Soundings, May/June
2008).
Landscape. Maintain the natural state of the site.
Use native and drought-resistant plants, and minimize lawn areas.
Use trees to shade parts of the building or let sun reach the
building during specific times of the day/seasons to reduce or
increase heat gain into the building. (For more information, see
"Native Landscaping," November/December 2006.) Be sure to include a
water runoff plan to retain water on-site with the landscape
design. Avoid hard, impermeable surfaces.
Surgical sitework. Many coastal builders are
already required to minimize site impacts and limit water runoff,
but there is always room for improvements to preserve precious
coastal wetlands. On this Sarasota County site, an engineered
wetland is underway to offset the impact of nearby building
sites.
Indoor air quality and
maintenance
Two other chief concerns arise in the green building arena: indoor
air quality and operation/maintenance issues. However, there is
nothing particularly coastal about these topics, though maintaining
low indoor humidity levels might be more challenging in many
coastal climates. Controlling indoor air quality starts with
building a tight building envelope and installing a balanced
ventilation system, but it also involves strategies for keeping
pollutants out of the home. One place to begin gathering the
requisite knowledge on the issues is the Healthy House Institute
(www.healthyhouseinstitute.com).
Mike Guertin (www.mikeguertin.com) is a custom
home builder and remodeler in East Greenwich, R.I., and a member of
the JLC Live Construction Demonstration Team (www.jlclive.com). Clayton
DeKorne is editor of Coastal Contractor. All articles
referenced from Coastal Contractor can be found at www.coastalcontractor.net.