Roxul ComfortBoard IS - Manual (Page 32)

ROXUL
® The Better Insulation™ 30
ROXUL
®
Building Science Notes
01. GENERAL
a. Detail is applicable to light-weight cladding systems including vinyl siding, wood siding, and fiber cement siding or
panels with ROXUL COMFORTBOARD IS thicknesses greater than 1.5” (38 mm). For heavy-weight cladding systems,
see ROXUL CAVITYROCK™ Application Guide. Detail is applicable for ROXUL COMFORTBOARD IS thicknesses less
than 1.5” (38 mm), with the exception that “perfect barrier” type cladding can be directly attached to framing through
insulation as per cladding manufacturer’s instructions.
02. STRUCTURE
a. A wood frame is illustrated in this detail. Alternates for the infill wall structure include light gage metal stud with
exterior gypsum board sheathing and a CMU structural wall.
03. RAIN WATER CONTROL LAYER
a. A drained-screen approach to rain water control (as illustrated) is recommended.
b. The drainage plane material is the primary rain water control layer in the wall assembly. Water penetrating the
exterior cladding must be directed to the exterior by this layer.
c. Material options for the drainage plane shown in the wall assembly above include:
i. non-perforated housewrap or building wrap
ii. building paper
iii. vapor permeable liquid or fluid applied membrane
iv. vapor permeable “peel and stick” self-adhered membrane
v. vapor impermeable membranes may be used depending on vapor control design (see section 06 below)
04. AIR CONTROL LAYER
a. The drainage plane may be detailed as the primary air control layer if made continuous.
b. If an air permeable cavity insulation is selected an airtight drywall approach should be used. An airtight drywall
approach requires all penetrations of the gypsum board to be carefully sealed.
c. Multiple planes of airtightness are recommended where practical to control convection within the enclosure cavity.
05. THERMAL CONTROL LAYER
a. ROXUL COMFORTBOARD IS insulation is the primary thermal control layer.
b. The amount of insulation recommended varies by climate region (see Table 2 )
06. VAPOR CONTROL LAYER
a. The assembly as illustrated is a “vapor open” assembly, meaning that there is a single line of vapor control and that
drying can occur towards the interior or towards the exterior from this line. Selection of vapor-open interior finishes
should be considered. If vapor impermeable finishes are used, analysis should be conducted to assess drying
potential.
07. EXTERIOR CLADDING
a. A drained and back-ventilated wood or fiber cement siding is illustrated.
b. Increasing the air-gap reduces the amount of solar driven inward vapor drive
c. Material options for the exterior cladding include:
i. Vinyl siding (see manufacturer’s notes for installation on furring)
ii. Wood siding
iii. Fiber cement siding or panels
08. QUALITY CONTROL CONSIDERATIONS
a. Inspect the lapping of drainage plane pieces to ensure that pieces are installed in “shingle” fashion.
b. Ensure a tight fit where the exterior insulation boards are fit together. At mechanical and structural penetrations, an
opening in the ROXUL COMFORTBOARD IS layer may be cut slightly undersized to ensure a tight fit.