Roxul ComfortBatt - Manual (Page 12)

12
Better | Best
Thermal insulation systems for
residential exterior wall applications.
As society demands more energy-efficient houses,
building codes and builders (and dIY homeowners)
are responding by increasing the R-value of the
building enclosure, in particular, the above-grade
exterior wall. Given that the cavity of the standard
2 x 6 wood frame wall used in residential housing
(new construction) is already filled with insulation,
the clear path forward to higher R-values is to
add layers of exterior insulation.
ROXUL COMFORTBOARd ™ IS is a rigid stone wool
insulation board fastened to the outside face of the
exterior studs used in residential construction and
designed to provide increased thermal performance
to the building envelope.
As building codes adjust to increased effective R-value
requirements, the need for insulated sheathing will
increase accordingly, and COMFORTBOARd
™ IS leads
the way as the exterior insulation of choice for
residential applications.
What makes ROXUL COMFORTBOARD IS
a superior exterior insulation sheathing
More “Breathability” than Foam Plastics
COMFORTBOARd
™ IS is a moisture resistant, yet vapor
permeable insulation (30-40 perms) and will allow
transient vapors to pass through with little restriction.
This unique vapor permeable quality of ROXUL
® ’s
cavity wall insulation allows for an increased potential
for drying “breathability” without trapping moisture
in the wall assembly.
Lower permeable insulations such as foam plastics can
act as vapor retarders and negatively affect the drying
potential of many typical residential wall assemblies.
Fast Outward Drying
Highly permeable insulation like COMFORTBOARd IS
has the added benefit of allowing fast outward drying
during cold weather. This dries the wood-frame cavity
very quickly, even if the framing is wet from construction
or becomes wet because of incidental water leaks.
How to insulate a typical above-grade
exterior wall
Exterior walls should be insulated to their maximum
R-value, in part, determined by the thickness of the
stud wall. If your walls are constructed with 2 x 6
studs, then COMFORTBATT
® R-24 batts should be
used. R-24 batts are 5 ½ inch thick and snugly fit
intoa 2 x 6 cavity wall.
When installing COMFORTBATT between the wall
studs, eliminate any gaps and ensure the ends butt
snugly together. Ensure the surface of each batt is
flush with the interior surface of the studs.
Determining your climate zone and
building code requirements
In the northern states chances are that building
codes mandate a vapor control layer be installed on
the warm side of the insulation. A vapor control layer
in northern climates helps to reduce the moisture
diffusion through the wall assembly and through to
the drywall. Vapor control layers and barriers have
different permeance levels measured in perms,
and depending on your building code, you may
need to install a vapor control layer with a specific
perm rating. In some northern US states, a 6 mil
polyethylene sheet is commonly used, but always
check with your local building code for guidance.
Installing vapor barriers
Typically, a vapor barrier/retarder (e.g. poly sheeting)
is installed on the warm side of the wall, over the
insulation and studs. If a single membrane is used as
a combined air/vapor barrier, seal all vapor barrier
seams with suitable tape to completely seal the wall
and eliminate any chance of warm air getting into the
wall cavity, where it can contribute to condensation and
cause mold problems.
*
*Check with your state/municipal building code for approved vapor barrier/retarder information.