Page 21 - Green Builder Sept-Oct 2016

CONTINUOUS INSULATION
There are many advantages to using continuous insulation instead
of cavity insulation. First, walls with continuous insulation have
high R-values, as no heat is lost or gained from steel studs (or wood).
Second, continuous insulation reduces the chance of moisture
damage, because water is unable to condense on the inside face of
the sheathing, according to GreenBuildingAdvisor.com.
However, continuous insulation has led to issues with the
installation of windows. Home Innovation Research Labs is working
to develop performance information and establish criteria to evaluate
windows with flanges supported by insulating materials. It’s testing a
variety of windows and foam sheathing under two loading scenarios:
temporal wind pressure loading and long-term gravity loading. This
will assess the performance of a number of different combinations
of windows, and foam sheathing types and thicknesses.
Preventing energy loss. Home Innovation Research Labs is
developing solutions for insulation in existing homes’ attics with
cathedral ceilings, habitable space or those used for storage.
ATTIC INSULATION
It’s no secret that much of a home’s energy loss is due to a poorly
insulated attic. Improvements in insulation have largely resolved
this issue in new builds. In retrofits, the problem isn’t as easily
solved. Sometimes, better air sealing and installing extra insulation
is enough to prevent energy loss. But those techniques are not options
for many retrofits, such as those including attics with cathedral
ceilings, habitable space or those used for storage.
For attics that are not easily insulated, Home Innovation Research
Labs is looking into nail-based insulated panels as a solution.
Solutions for attics. Nail-based insulated panels developed by
Home Innovation Research Labs can prevent heat loss in a variety
of attics in existing homes.
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CREDIT: CREATIVE COMMONS
CREDIT: HOME INNOVATION RESEARCH LABS Though the interface of the tool isn’t 100 percent certain, Jackson
Determining the Best
Building Envelope
T HE OAK RIDGE Natural Laboratory (ORNL) is working
to develop a tool for builders to determine the best wall
assemblies for specific projects. “As we move toward higher
performing buildings and envelopes, we’re asking builders
to do things they haven’t done before,” says Roderick Jackson, group
leader of building envelope systems research for ORNL’s Building
Technologies Research & Integration Center. “High-performance systems
have information builders can use, but it’s not easy to access.”
ORNL’s tool will provide the building community with simple, easy-
to-access information about building envelope options. Builders will
be able to specify what kind of cladding and insulation they will use,
or the location in which they want to build. Based on the information
provided, the tool will tell builders the wall assembly that will be the best
option. In addition, if a builder has a specific wall assembly they want to
use, they can tell the tool more detail about the project and location.
The tool will use that information to determine whether an assembly
is a good option.
To develop the tool,
ORNL measured certain
performance indicators,
including the risk of wood
decay, mold, mildew
and other factors that
would impact IAQ. It ran
simulations to determine
the performance of walls CREDIT: ORNL
in many different homes.
Then, it studied these
results of simulations in a Wall assembly selection. ORNL’s new tool
probabilistic way, which will help builders select the best wall
means they measured assembly for their specific project.
the spread of results, versus
taking an average of the simulation results.
“We looked at a wall and determined the risk of moisture problems,
how much moisture activity occurs inside the home, the amount of
moisture in the outdoor climate or how much air is leaking through a
wall,” says Simon Pallin, researcher in ORNL’s Buildings Technologies
Research & Integration Center. “We looked at all of these parameters
with probabilistic view.”
When a builder enters information to determine the best wall assembly,
the results from all simulations that could affect the builder’s experience
are taken into account.
believes it will be modeled after a traffic light. If a builder has a wall
assembly they want to use, they enter information about the project
into the tool, including the type of structure, insulation and location.
The tool will show a green, yellow or red light. Green means the wall
assembly is a good option; yellow means it could be a good option, but
some guidelines need to be followed; and red means it’s not a good
option for that project. Builders also will be able to compare a number
of different potential wall assemblies side by side.
September/October 2016 GREEN BUILDER 19