Roxul ComfortBoard IS User Manual
Page 34
ROXUL
®
The Better Insulation™
32
ROXUL
®
Building Science Notes
01.
GENERAL
a.
Detail is applicable to grade-level wall-to-basement or crawlspace stem wall interface.
02.
STRUCTURE
a.
A site-cast concrete foundation wall and floor slab is pictured. A CMU foundation wall is an alternate.
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.
Other air barrier system components include the concrete structure, sealant at the rim joist and other framing
connections, and the sill gasket.
c.
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.
d.
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
c.
An adequate thickness of insulating sheathing must be provided outside of the rim joist to prevent air leakage
condensation from occurring in this location (see
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.
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 transitions from below- to above-grade wall.
c.
Ensure that the finished grade is sloped away from the building.