ROCKWOOL Comfortbatt Semi Rigid Batt Insulation Installation Guide
- June 13, 2024
- ROCKWOOL
Table of Contents
Comfortbatt Semi Rigid Batt Insulation
Product Information
The ROCKWOOL insulation is designed to restrict heat flow and
provide effective thermal resistance. It has a high R-Value,
indicating its ability to insulate and retain heat. The insulation
does not absorb water or hold moisture, ensuring that it will not
sag or lose its shape over time. It is suitable for residential
installations and meets or exceeds the thermal performance
requirements recommended by the International Code Council (ICC)
and the U.S. Department of Energy (DOE).
What is R-Value?
R-Value is a measurement of the insulation’s ability to restrict
heat flow. The higher the R-Value, the better the insulation’s
insulating power.
Stated R-Value vs. Effective R-Value
The stated R-Value only measures thermal resistance and does not
consider factors such as structural elements that bypass the
insulation. The effective R-Value takes into account these
additional factors, providing a more accurate measurement of the
insulation’s performance.
Government Recommended R-Values by Climate Zone
The ICC and DOE recommend specific R-Values based on climate
zones to ensure optimal thermal performance. These recommended
R-Values exceed the requirements of most building codes.
Attic Insulation R-Value
The attic is an important area to insulate in a home. The DOE
recommends up to R-49 for attics in most climate zones, which is
approximately 16 inches of blanket insulation. Older homes
typically have between 3 and 6 inches of insulation. To determine
the required insulation thickness, measure the existing insulation
and refer to the NAIMA chart for DOE recommendations based on the
home’s location.
Benefits of Proper Attic Insulation
A properly insulated attic can significantly reduce heating
bills by 10 to 50 percent, according to the DOE. It also helps
stabilize indoor temperatures in warmer climates, reducing cooling
needs.
Product Usage Instructions
Site Preparation and Personal Protective Equipment
(PPE)
Before starting the insulation installation, ensure proper site
preparation and wear appropriate personal protective equipment
(PPE). This includes gloves, safety goggles, and a dust mask to
minimize dust exposure.
Tips for Controlling and Reducing Dust
When handling the insulation, follow these tips to control and
reduce dust:
-
Minimize cutting or trimming the insulation to reduce dust
generation. -
Use a sharp knife or insulation cutter for precise cuts.
-
Keep the work area clean by regularly removing loose insulation
and debris. -
Dispose of insulation scraps properly to prevent dust
contamination.
Installing Attic Insulation
To install the ROCKWOOL insulation in the attic, follow these
steps:
-
Carefully remove any existing insulation, if necessary.
-
Measure the thickness of the existing insulation to determine
the required R-Value. -
Refer to the NAIMA chart or the DOE recommendations for the
specific climate zone to determine the appropriate thickness of
ROCKWOOL insulation. -
Cut the insulation panels to fit between the attic joists,
ensuring a snug and continuous fit. -
Secure the insulation in place using appropriate fasteners or
insulation supports. -
Avoid compressing the insulation, as it reduces its
effectiveness. -
Repeat the process until the desired R-Value is achieved.
-
Inspect the installed insulation for any gaps or areas that
require additional coverage.
For more detailed information and installation guidelines,
please refer to the complete user manual or visit the official
website at
www.naima.org/insulation-knowledge-base/residential-home-insulation/how-much-
insulationshould-be-installed.html.
ROCKWOOL Comfortbatt®
Residential Installation Guide
Contents Section 1: R-Value ……………………………………………………………………………….. …3 · The
difference between stated R-Value and effective R-Value · Government
recommended R-Values by climate zone · How to determine an attic’s Insulation
R-Value · How to determine how much insulation a home needs Section 2: Site
preparation and PPE…………………………………………………………. 6 · Tools/Equipment required ·
Protective gear · Tips for controlling and reducing dust · Air sealing ·
Safety Section 3: Insulation project scenarios ……………………………………………………. 8 a)
Attic b) Cathedral Ceiling c) Exterior Wall d) Basement Wall e) Crawlspace
vented and and non-vented Section 4: FAQs ………………………………………………………………………………….. 22
Section 5: Attachment of Board Insulation………………………………………………. 26
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1
R-Value
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R-Values
What is R-Value? R-Value is the measurement of the insulation’s ability to
restrict heat flow. The higher the R-Value, the more insulating power it
provides. Batt insulation works by restricting the air movement in the
insulation. Higher density insulation results in higher thermal resistance.
What is the difference between stated
R-Value and effective R-Value? Stated R-Value tests measure only thermal
resistance. It does not take into account factors such as:
· Air infiltration due to leakage through gaps
· Permeability of system components · Convection flows within the wall system
· Thermal mass of components
· Thermal bridging across the building envelope
While the stated or nominal R-Value of an insulation product is an indicator
of the material’s thermal resistance, the effective thermal resistance
accounts for the structural elements that bypass the insulation.
Government recommended R-Values by climate zone
The International Code Council (ICC) publishes the International Energy
Conservation Code (IECC), which recommends specific thermal performance
requirements. The U.S. Department of Energy (DOE) bases its R-Value
recommendations for existing homes on specific heating and cooling needs and
the cost of energy across the country and ZIP code. The R-Values recommended
by DOE exceed those required by most building codes.
6
7
6
4
5
3 2
4 2
5
3 2 1
In real-world performance, the installation of ROCKWOOL Comfortboard® 80 as the exterior continuous insulation (C.I.) and ROCKWOOL Comfortbatt® as the wall cavity insulation results in a building envelope that has a higher combined thermal performance than the two products used separately, and an overall improved effective R-value with reduced thermal bridging through the studs.
ASHRAE map of climate zones Every rating agency has its own maps that divide
regions into thermal or climate zones to tailor codes and standards to what is
appropriate for that particular region.
www.naima.org/insulation-knowledge-base/residential-home-insulation/how-much-
insulationshould-be-installed.html
What’s more, ROCKWOOLTM insulation does not absorb water or hold moisture. It will not sag or lose its shape, and will retain its R-Value. So, the R-Value installed today will be the same for years to come.
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How to determine an attic’s insulation R-Value
The attic is one of the easiest and most important areas of a home to
insulate.
The DOE recommends up to R-49 for attics in most climate zones. This is equal
to approximately 16″ of blanket insulation. Most older homes have between 3″
and 6″ of insulation.
To learn how much insulation a home might need, simply measure the thickness
of the attic’s existing
ilnocsaullaintisounlatwioitnhcaonrutrlaecr,toarntdocdoenttearcmt iynoeur the
approximate R-values based on the insulation type.
Then check the NAIMA chart to see what the DOE recommends for the area where
the home is located.
How to determine how much insulation a home needs It’s easy to calculate the
number of insulation packages needed to complete a project:
· Multiply the area length by the width to determine total square footage to
be insulated.
· Measure the distance between joists or studs to determine correct insulation
width for the job (16″ or 24″).
· Choose the appropriate insulation product (R-Value, thickness and width) for
the home insulation project.
· Choose the insulation product width to match distance between joists or
studs–16″ or 24″. If the joist cavity is full, insulation width makes no
difference because you should install new insulation across the top of the
joists.
· Divide total square footage to be insulated by square footage per package.
Round up to the next whole number to determine total number of packages
required.
While most attics are insulated, over time, loose fill insulation can settle
and compact, reducing its R-Value.
The Department of Energy estimates that a properly insulated attic can shave
10 to 50 percent off your heating bill. And it works the opposite way for warm
climates; in summer, it helps stabilize a house’s indoor temperatures to keep
cooling needs in check.
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2
Site preparation and PPE
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Site preparation and PPE
Site preparation and personal
Tips for controlling and reducing dust
protective equipment (PPE)
Another important safety consideration when handling
Insulating is a safe DIY project when the insulation is
insulation is dust control. These recommended work
installed properly. Refer to the following tool checklist and practices help to minimize itching of the skin.
tips before beginning insulation projects.
1. Store the material to protect against damage.
Gather the proper equipment, tools and protective clothing
Special equipment · Portable work light
2. Unpack the material at the installation site.
3. Cut the insulation on a flat surface. Use a sharp knife with serrated
edge. Don’t use a saw, unless hard roof boards need to be cut.
· Boards or sheets of plywood (provide a safe place to sit or kneel in an
unfinished attic and a surface on which to cut the insulation)
· Insulation supports (for holding the insulation up under floors)
· Pole or rake (for pushing insulation into out-of-the-way places in
attics/flat ceilings)
Basic tools · Tape measure · Knife or insulation saw a knife with a serrated
blade is
best. Blades should be replaced periodically as they tend to dull during use.
· Straightedge or 2 x 4 (for cutting insulation) · Screw gun (drill) and
appropriate fasteners when
installing board products
4. Open a door or open a window to ensure good ventilation.
5. Organize workplace in a manner that makes all installation easy.
6. Cover open ventilation ducts to reduce particulate in the ducts.
7. In confined spaces with poor ventilation, use protective goggles and a
dust mask.
8. Keep workplace clean. Prevent whirling dust. Use a vacuum cleaner, not a
broom.
9. If skin irritation occurs, don’t rub. Wash the area in cold water. Change
clothes and wash on completing work.
10. Do not use compressed air for clean-up unless there is no other effective
method. If compressed air must be used, other workers must leave the site.
Protective gear · Work gloves, loose-fitting, long-sleeved shirt,
11. Avoid unnecessary handling of scrap materials by placing them in waste disposal containers before removing them from the site.
· long pants and cap · OSHA-approved safety glasses · Disposable dust
respirator is recommended, but not
required (NIOSH-certified N95 or greater)
Safe Occupancy
There are no re-entry / re-occupancy requirements for this project. You may
re-enter the premises immediately following installation.
Air sealing
Proper air sealing should be completed prior to ROCKWOOL Comfortboard®,
ROCKWOOL Comfortbatt®, insulation to ensure full performance of the
insulation. Verify all holes and seams between sheet goods such as drywall,
sheathing, and subflooring at the building envelope are sealed with the
durable caulk, tape, and/or foam seals.
Safe Occupancy
Section 410-66, of the 1978 National electrical Code states: Recessed portions
of enclosures, other than points of support, shall be spaced at least ½ inch
from combustible materials. Thermal insulation shall not be installed within 3
inches of the recessed fixture enclosure, wiring compartment or ballasts and
shall not be installed above the fixtures as to entrap heat and prevent free
circulation of air unless fixture is otherwise approved for that purpose.
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3
Insulation project scenarios
ROCKWOOL Comfortbatt®
ROCKWOOL Comfortbatt® is a stone wool thermal insulation product for use in
wood and steel framing in both new residential and commercial builds and
renovations. This semi-rigid batt has a unique flexible edge designed to
compress as the batt is inserted into walls, attics, ceilings and floor
frames.
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Insulation project scenarios
ROCKWOOL Comfortbatt® installed in exterior walls is a great way to save energy, but there are other applications that can make a big difference in your home’s comfort. Insulating the exposed concrete walls in basement and heated crawl spaces, as well as increasing the insulation in your attic, are all effective ways to improve your home’s energy efficiency.
Cathedral ceilings
Attics
Exterior walls
Basement walls
Exposed floors
Heated crawl spaces
How to Install ROCKWOOL Stone Wool Insulation
ROCKWOOL insulation cuts quickly and accurately with a knife for fitting
around pipes, electrical boxes, wiring, ductwork, and between studs and joists
that are less than a standard width.
Installation Equipment: Wear long-sleeved, loose-fitting clothing and proper
gloves for handling insulation. Tools needed:
· Tape measure
· Long serrated bread knife
· Straight edge
· Approved vapor barrier/retarder if required by local building codes
· Staple gun (when vapor barrier/retarder is required)
ROCKWOOL Comfortbatt® higher density batts make it simple for precise cutting to ensure a fit without gaps and voids.
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Attic
If you want to increase home comfort and save energy year `round, start by
reducing the heat loss through the attic, the most cost-effective place to add
insulation. If the current insulation has
settled and isn’t flush with the top of the joists, add an extra layer of ROCKWOOL Comfortbatt® thermal batt insulation to bring it up to the top of the joist.
1
Step 1
Install Comfortbatt® between joists. Butt ends tightly together to eliminate any gaps.
2
Step 2
For additional insulation, lay a second layer of insulation perpendicular to the first layer.
Can ROCKWOOL insulation be placed in contact with hot objects? ROCKWOOL
insulation products should not be placed in direct contact with hot surfaces.
Gaps and clearances in accordance with local codes shall be maintained.
1 2″ x 8″ Roof Trusses 2 ROCKWOOL Comfortbatt® (R22) 3 ROCKWOOL Comfortbatt®
(R28) 4 Vapor Control Layer*
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1 3
4
2
For existing construction
1
2
When no insulation is present: 1. Install Comfortbatt® between joists
2. For additional insulation, lay a second layer of insulation perpendicular to the first layer.
When existing insulation is present: · Level existing insulation to top of
joist.
· Lay Comfortbatt on top of joists running perpendicular to the first layer.
· Ensure batts are butted against each other tightly. · Fit batts closely to
cross joists: cut batt if necessary;
leave no space between layers.
· In a vented attic (refer to the Construction Details section), the
installation of baffle (on-site or pre-formed) is recommended to allow
adequate air flow. Consult with baffle manufacturer’s installation guidelines
for further information.
· Insulate attic hatch to same level as rest of attic.
· Apply weatherstripping to edge to reduce air leakage. · Only insulate close
to IC-rated electrical fixtures.
· Follow manufacturer’s instructions and local building code to insulate
around chimney.
Insert. Compress. Release.
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Cathedral Ceiling
The rafters in cathedral ceilings are usually made of 2 x 10s or 2 x 12s and ROCKWOOL Comfortbatt® is ideal for insulating around those rafters.
Maintaining a minimum two inch of air space between the insulation and roof
deck is recommended to help prevent moisture damage and ensure long roof
life.
Step 1
In cathedral ceilings, the insulation should be held in place by pressure
against the sides of the rafters.
Step 2
An air space between the insulation and roof sheathing, (most building codes
call for a minimum of 2″ of air space) ventilated at ridge and soffit, is
desirable in cathedral ceilings.
Note: If unfaced material is used, a separate vapor retarder may be required
facing the living area after the insulation has been installed.
1 2
4
3
1 Shingles
2 Sheathing
5
3 2″ x 10″ Roof Trusses
4 ROCKWOOL Comfortbatt® (30/32)
5 Gypsum
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Exterior walls
Exterior walls should be insulated as much as possible. If walls are constructed of 2 X 6 material, then ROCKWOOL Comfortbatt® R22/23 (5½”) batts should be used. Do not attempt to squeeze 5.5″ batts into a 2 X 4 stud wall.
Air sealing
Air sealing is important for controlling heat loss and reducing condensation
risk. There must be a continuous uninterrupted airtight plane from wall
elements to other components for the enclosure such as windows, roof and
foundation assemblies. Sealing all joints, penetrations and transitions before
installing insulation is critical in achieving airtightness.
1
Step 1
Insert the batt tight to the wood stud and top plate, eliminating any gaps, compress the batt to fit snug in the wall and release.
2
Step 2
Do not flatten the insulation as this reduces effectiveness.
3
Step 3
Install vapor retarder where required.
While many contractors feel that
polyethylene is the best choice, always
consult your local building code.
ROCKWOOL Comfortbatt® Thermal Home Insulation keeps a home warm in the winter
and cool in the summer for more comfortable living all year round.
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Thermal insulation systems for residential exterior wall applications
As energy efficiency and thermal performance demands continue to increase,
building codes, builders and 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 wood frame wall used in
residential housing is already filled with insulation, the clear path forward
to higher R-Values is to add additional continuous insulation on the exterior
side of the wall.
ROCKWOOL Comfortboard 80 is a rigid stone wool insulation board fastened to
the outside face of the exterior studs and on the outer face of the exterior
sheathing, designed to provide increased thermal performance to the building
envelope.
What makes ROCKWOOL Comfortboard 80 a superior exterior insulation sheathing?
High Drying Potential Comfortboard 80 is a moisture-resistant, yet vapor
permeable insulation and will allow transient vapors to pass through without
restriction. This unique vapor permeable quality of ROCKWOOL stone wool
insulation allows for an increased potential for drying without trapping
moisture in the wall assembly.
Fire Resistance ROCKWOOL Comfortboard 80 and ROCKWOOL Comfortbatt are
noncombustible and fire resistant, able to withstand temperatures of 2150 F
(1177 C), will not fuel the spread of a fire, or contribute any significant
toxic smoke. Adding Comfortboard 80 on in your walls can increase the fire
resilience of your home.
If the home is older and built with 2 x 4 studs for the exterior walls, never
attempt to squeeze Comfortbatt R-23/24
into the wall cavity. Compressing the insulation will cause it to lose its
effective R-Value instead install
ROCKWOOL Comfortbatt R-14/15.
Another option to improve the wall’s thermal performance is to build out the
studs by adding 2 x 2 strapping/furring to the existing edges of the 2 x 4
studs, which will create a 2 x 6 stud wall.
Comfortbatt R-23/24 can then be added
to the expanded deeper cavity and end up with increased insulation R-Value.
Vapor retarders in cold climates Typically, a vapor retarder is installed on
the warm side of the wall, over the insulation and studs. Use the least amount
of staples that will hold the vapor retarder up, seal all vapor retarder seams
with suitable tape to act as an air barrier. This reduces the chance of warm
air getting into the wall cavity, where it can contribute to condensation and
cause mold problems.
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Basement walls
To reduce overall heating and cooling costs, it pays to insulate the interior foundation walls. R-Values can be increased by installing a combination of two ROCKWOOL insulation products: Comfortboard® 80 and Comfortbatt®
thermal insulation. Before starting, check basement walls for signs of dampness. If damp, have the foundation checked for cracks. Ideally, wait a minimum of one year after construction to allow for the foundation to settle.
1
Step 1
Clean surface and remove all debris from concrete walls. Mechanically fasten Comfortboard 80 to the exterior concrete wall. Refer to the ROCKWOOL Board Insulation Attachment Guide for
further guidance.
2
Step 2
Install 2 x 4 stud wall directly against Comfortboard 80, leaving no gaps or air space.
3 A
Step 3
A) Install 3.5-inch Comfortbatt thermal
insulation between studs.
B
B) ICgnuositndasalulnlvctaelpooocnar ltrhaetreaeuradsbeeruoiwfldahinevgraepcoroerdqeusirfeodr.
retarder.
The combination of ROCKWOOL Comfortboard® 80 and ROCKWOOL Comfortbatt® ensures
optimum long-term thermal performance from basement wall assembly.
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Crawlspace
Many home and cottage owners can enjoy additional benefits by insulating their crawl spaces. In some cases, the most difficult aspect of insulating a crawl space is having enough room to work around to properly install the insulation. If the crawl space area is easy to get at, the installation of ROCKWOOL insulation is quite simple.
Typically, there are two types of crawl spaces they are defined by either being vented or non-vented. The difference in how the two crawl space types are insulated is defined by either applying insulation to the exterior wall, or to the ceiling/floor between the heated living space and the crawl space.
ROCKWOOL Insulation: a two-tiered solution to insulating crawl spaces ROCKWOOL
has two thermal insulation products for interior crawl space wall assemblies:
ROCKWOOL Comfortboard® 80 (Insulation Sheathing) and ROCKWOOL Comfortbatt®.
When used in tandem within the 2 x 4 stud wall cavity, these two products help
create a drier, more comfortable space.
A vented crawl space can be notorious for dampness, but ROCKWOOL insulation is
water-repellent, moistureresistant yet vapor-permeable. The permeance of
ROCKWOOL products allows moisture vapor to pass through the insulation without
being trapped. In the unfortunate event of basement leak where the insulation
becomes wet, ROCKWOOL insulation quickly dries out and maintains its R-Value.
ROCKWOOL won’t absorb water and is not susceptible to mold.
Comfortboard® 80 and the effects of thermal bridging Before recommending the
Good, Better, Best R-Values for the crawl space wall assembly, we need to
understand thermal bridging the process that describes a material’s capacity
to conduct heat from one material to another.
In a typical crawl space, cold air transfers from the outside concrete
foundation through the wood studs and eventually into the living space. The
studs perform as the conduit or “thermal bridge”, lowering the R-Value of the
wall assembly. A continuous layer of insulation such as Comfortboard 80
installed against the studs reduces this thermal bridging, blunting the effect
of thermal bridging between the concrete and the studs.
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Vented crawl space installation
Vented simply refers to the space having air vents, typically more than one, and they are generally located across from one another at the upper part of the foundation wall. The vents allow for an air exchange, helping to eliminate dry rot, moisture build-up, and other conditions that can develop in these enclosed spaces. This type of venting would be very common in older homes.
A vented crawl space is treated in the same manner as a cantilever, or insulating a room where the underside is exposed. The underside of the floor is insulated by adding batt insulation between the floor joists.
1 2 3A
Step 1
Seal all joints and penetrations with caulk and where required by local
building codes, install a vapor retarder to the underside of the sub-floor
before insulating.
Step 2
Insert, Compress and Release to install ROCKWOOL Comfortbatt thermal
insulation between the floor joists.
Step 3A
Permanently hold the insulation in place by installing strapping on the
underside of the floor joists perpendicular to the insulation. Attach minimum
2 pieces of strapping using appropriate screw, nails or staples. Some options
for strapping include wood, plastic, wire and chicken wire mesh. At least one
piece ofstrapping should be installed for every 8 inches of insulation.
Step 3B
Install an impermeable, foil faced insulating sheathing (taped or sealed
joints).
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ROCKWOOL insulation products for vented crawl spaces
R-30
2 x 10 Joists + R30/R32
(or attach 1 x 2 furring/strapping strip to 2 x 8 joist to build up the joist
cavity depth)
1 2 x 10 Joists 2 Vapor Control Layer* 3 ROCKWOOL Comfortbatt® (R30/32) 4
Foundation Wall
3
1
2
4
- Consult your local authority having jurisdiction on the proper location and installation for the vapor barrier/retarder.
Can ROCKWOOL insulation be placed in contact with hot objects? ROCKWOOL insulation products should not be placed in direct contact with hot surfaces and gaps and clearances in accordance with local codes shall be maintained.
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Non-Vented crawl space installation
A non-vented crawl space is defined as having a heating Dirt floors of a non- vented crawl space should be
or cooling source, or some other source that conditions covered with a suitable vapor retarder before insulating.
the air within the crawl space. Conditioning the room
All joints of the vapor retarder shall overlap by 6 inches
helps to minimize moisture build-up in the space, and
(153 mm) and be sealed or taped. The edges of the
helps to avoid the growth of mold.
vapor retarder shall extend at least 6 inches (153 mm) up
the stem wall and shall be attached to the stem wall.
A non-vented crawl space is insulated in the same manner Walls of a non-vented crawl space should be insulated in
as a conditioned basement. The exterior foundation is
exactly the same manner as a basement wall.
framed in with studs, and the insulation is then installed
between the studs.
1
Step 1
Mechanically fasten ROCKWOOL Comfortboard 80 to the exterior wall.
2
Step 2
Install 2×4 stud wall directly against ROCKWOOL Comfortboard 80.
3
Step 3
Install ROCKWOOL Comfortbatt thermal insulation between studs.
4
Step 4
Where required by local building code, staple vapor retarder to studs then tape and seal joints.
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Non-Vented crawl space systems
Basements and non-vented crawl space walls Header (rim-joist) If the
basement / crawlspace header (rim-joist) needs to be insulated see Basement
Header and Bottom Plate Details diagram:
1. Caulk or spray-foam any gaps and cracks,
2. Install R22/R23 ROCKWOOL Comfortbatt® thermal insulation into the rim-
joist,
3. Where required by local building code, staple vapor retarder to floor
assembly and connect to header wrap (if present)
Basement and non-vented crawl space walls bottom plate The bottom plate of
an insulated wood stud wall installed against a basement or crawl space wall
needs to be damp-proofed and sealed.
1. At the bottom plate install a thick bead of caulking on the concrete (or
vapor-retarder) floor.
2. Staple 12″ of vapor retarder to the bottom of the wall bottom plate.
3. Install wood stud wall 4. Where required by local building code, connect
the
interior vapor retarder with the 12″ vapor retarder at the bottom plate and
seal with tape.
1 Header Wrap (Installed from foundation wall to under main floor bottom
plate)
2 Fasten vapor retarder to floor assembly (sub floor and floor joist as
needed)
3 R22 ROCKWOOL Comfortbatt to cover the foam to top of insulated wall (thermal
protection of foamed plastics)
4 Spray foam/caulking air sealant to act as an air barrier
5 Connect vapor retarder to header wrap at top plate
1 Vapor retarder
2 Pressure treated bottom plat
3 12″ of vapor retarder; staple to bottom of bottom plate; tape over poly that
runs down the interior face of the wall
4 Thick acoustic caulking bead for air seal between bottom plate & floor slab
5 Interior acrylic caulking sealant at the sub floor/plate joint as
alternative to under bottom plate
- Consult your local authority having jurisdiction on the proper location and installation for the vapor barrier/retarder.
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ROCKWOOL insulation products for non-vented crawl spaces
Good: R-15
2 x 4 Studs + R14/R15
1 Foundation Wall
2
2 2 x 4 Studs
3 ROCKWOOL Comfortbatt® (R14/15)
4 Vapor Control Layer*
1 3
4
Better: R-21
2 x 4 Studs + R6 Board
4
+ R14/R15 Batt
1 Foundation Wall
2
2 ROCKWOOL Comfortboard® 80 (R6)
3 2X4 Studs
4 ROCKWOOL Comfortbatt® (R14/15)
5 Vapor Control Layer*
1 3
5
Best: R-23/26
2 x 4 Studs + R8 or
4
R 12 Board + R14/R15 Batt
2
1 Foundation Wall 2 ROCKWOOL Comfortboard® 80
(R8 or R12) 3 2X4 Studs 4 ROCKWOOL Comfortbatt® (R14/15) 5 Vapor Control
Layer*
1 3
5
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4
Frequently asked questions
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Frequently asked questions
What is R-Value? R-Value is the measurement of the insulation’s ability to
prevent heat flow. The higher the R-Value, the more insulating power it
provides. Batt insulation works by restricting the air movement in the
insulation which slows heat movement.
What is the difference between stated R-Value and effective R-Value? Stated
R-Value tests measure only thermal resistance. It does not take into account
factors such as thermal bridging across the building envelope.
While the stated or nominal R-Value of an insulation product is important,
accounting for the thermal bridging will influence the effective R-Value of
the wall system.
If a vapor retarder is installed in an attic, is ventilation still required?
Yes. Even with a good vapor retarder, proper ventilation is considered
essential to prevent damage from condensation. Soffit vents openings at the
roof overhang combined with a ridge vent, roof vent or gable vents are
effective ways to create a positive movement of air in and out of the attic.
Insulation helps keep heat in during the winter months, but what is the
benefit to having it during summer months?
Insulation helps slow the process of summer heat entering the home, which
helps keep the inside cool and reduces the need for continuous air
conditioning.
What is a vapor retarder?
How does one add layers of attic insulation to a joist
A vapor barrier or retarder controls vapor transmission
cavity that is only half full?
and helps prevent condensation and excessive relative humidity levels within walls, floors and ceilings of a home. Vapor barriers/retarders are particularly important in Canada, and in states in the U.S. that experience winter temperatures below freezing.
If a joist cavity is only half full and the recommended insulation level in the home’s area is R-38, fill the joist cavity flush with the top with the appropriate thickness of unfaced ROCKWOOL Comfortbatt® insulation. Then lay a second layer of unfaced insulation perpendicular to the existing layer to give a total of 12″ (or an R-Value of 38) in
The three most common types of vapor retarders are; kraft the joist cavity. Covering the attic joists with the second
paper, foil-backed paper and polyethylene (a separate 4- layer will reduce heat loss through the wood.
to 6-mil polyethylene film applied over installed
insulation). There are other vapor retarder products such as smart vapor
retarder membranes or latex paint combined with gypsum board.
Do higher insulation levels create condensation problems?
Are ROCKWOOL insulation products required to be installed by a trained or
certified installer?
No, ROCKWOOL insulation products are available in standard dimensions.
Insulation can be quickly & easily installed by builders, homeowners and
DIYers.
Yes, potentially, but not if the building envelope is designed properly. Consult your local building regulation when doing any major renovations.
ROCKWOOL 23
What is ROCKWOOL insulation made of?
ROCKWOOL insulation is a rock-based mineral fiber insulation comprised of
basalt rock and recycled slag. Basalt is a volcanic rock, which is abundant in
the earth, and slag is a by-product of the steel and copper industry. The
minerals are melted and spun into fibers. The end product is called “stone
wool.”
Can ROCKWOOL insulation go around the pipe of a gas fireplace where the pipe
meets the exterior wall?
Although ROCKWOOL stone wool insulation is a noncombustible material, which
has a melting point of 2150 ºF, ROCKWOOL does not have any approvals for this
application. We recommend contacting the manufacturer and/or follow local
codes for this application.
Is ROCKWOOL insulation safe? Yes. A study showed that there were no increases
in risk of cancer for users or workers for the production of stone wool
insulation. The International Agency for Research on Cancer (IARC) has updated
the previous Monograph and classification of 1987, concerning the health
effects of various MMMF (Man-Made Mineral Fibers), excluding them from Group
2B (possibly carcinogenic). In addition, ROCKWOOL insulation is fire-
resistant. It can withstand temperatures up to 2150 ºF (1177 ºC).
Consequently, it does not contribute either to the development and spread of
fire or the release of toxic gases.
It is water repellent, which means that the insulation cannot absorb water.
Plus it resists rot, mildew, mold and bacterial growth, contributing to a
safer indoor environment.
What happens if ROCKWOOL insulation gets wet? ROCKWOOL insulation is moisture-
resistant yet vaporpermeable. In the event the insulation becomes damp or wet,
the insulation, when thoroughly dried, will maintain the original performance
characteristics.
Is ROCKWOOL insulation mold-resistant? ROCKWOOL products are inorganic,
providing no food source for mold to grow. ROCKWOOL products are tested to
ASTM C1338 Standard Test for Determining Fungi Resistance and pass with
zero fungal growth.
Does ROCKWOOL make blowing wool insulation? ROCKWOOL insulation is only
manufactured in batt, board, loose wool and pipe forms.
Is there any “off-gassing” from ROCKWOOL products? No, “off-gassing” is a term
that was started when blowing agents were utilized in insulation materials and
ROCKWOOL does not incorporate blowing agents in our products.
What is the fire rating of a ROCKWOOL product? A fire rating is determined by
testing a complete system, such as a wall with all its components, and not the
insulation alone. ROCKWOOL products are non-combustible and have an
approximate melting temperature of 2150 ºF, but cannot hold a fire rating by
itself, as is the case with any other insulation.
What is the difference between ROCKWOOL Comfortbatt® and ROCKWOOL
Safe`n’Sound®? ROCKWOOL Inc produces stone wool insulation products designed
and optimized for specific applications.
ROCKWOOL Safe’n’Sound acoustical fire batt insulation is designed, tested and
optimized for acoustical performance in interior wall assemblies; it is not
intended or routinely tested for exterior wall thermal application where
R-value is of interest.
ROCKWOOL Comfortbatt® thermal batt insulation is designed, tested and
optimized for thermal (R-Value) performance in exterior wall assemblies; it is
not intended or routinely tested for interior acoustic application where
decibel reduction is of interest.
It is always best to use the correct ROCKWOOL stone wool insulation product,
optimized for a particular application i.e. use ROCKWOOL Safe’n’Sound for
interior acoustic and fire applications and use ROCKWOOL Comfortbatt® for
exterior wall thermal applications.
Is a vapor retarder required on all applications using mineral wool
insulation? A vapor retarder may be required by the local building
jurisdiction based on the climate zone. Consult your local building
jurisdiction for clarification on the use of a vapor retarder.
A vapor retarder is only required when the application involves an exterior
wall. A vapor retarder is meant to restrict water vapor transfer from the warm
side and condense on the cold side of the wall. A vapor retarder is always
attached to the warm side of the insulation.
ROCKWOOL 24
Will ROCKWOOL insulation products pass building How much clearance is needed when insulating around
code inspections?
pot/recessed lights?
Yes, the insulation will pass building code inspections
Insulating around pot lights can vary by manufacturer,
as ROCKWOOL® tests to CAN/ULC S-702 Standard For as well as the type of pot light and it may be covered Mineral Fiber Thermal Insulation For Buildings, and ASTM under local building codes. ROCKWOOL has no set
C665 Standard Specification for Mineral Fiber Blanket
requirements for insulating around pot lights and
Thermal Insulation for Light Frame Construction and
would always recommend following the manufacturers’
Manufactured Housing as required by the NBCC (National recommendations and/or local building codes.
Building Code of Canada), the ICC (International Code
Council) and IBC (International Building Code). In addition, there are CCMC numbers on the Comfortbatt® products. As a result, ROCKWOOL insulation has met all the criteria needed for Canadian and United States residential codes.
What is the Specific Heat Capacity for ROCKWOOL products?
The heat capacity of ROCKWOOL products at 50 ºC is 0.8kJ/kg K (0.191 BTU/lb
ºF).
Can Comfortbatt® be used in my attic?
Yes, Comfortbatt® is designed for exterior walls and attics. Code requirements
for attic R-Value will vary from province to province, although R-40 is quite
common. To achieve R-40 in the attic using Comfortbatt®, it is recommended to
use two layers of R-23 for a total of R-46. Lay the first batt between the
roof trusses, then the second layer perpendicular to the first so as to cover
up the roof trusses.
Will ROCKWOOL insulation corrode metals?
No. ROCKWOOL products have been tested and conform to the stainless steel
stress corrosion specification as per the ASTM test methods C871 and C692.
ROCKWOOL 25
5
Fastener guidelines
ROCKWOOL 36
Attachment of Board Insulation
Board Products ROCKWOOL stone wool board products, such as ROCKWOOL
Comfortboard® 80, should be permanently attached using mechanical fasteners,
insulation pins or appropriate attachment measures based on the end-use
application.
Mechanical Fasteners For the permanent attachment of ROCKWOOL board
insulation, ROCKWOOL recommends the boards be mechanically attached using
mechanical fasteners with minimum 2″ diameter washers.
Number of Fasteners or Impaling Pins
When supporting ROCKWOOL semi-rigid and rigid insulation boards using only
mechanical fasteners or impaling pins, ROCKWOOL recommends a minimum of 5
attachments per board. When ROCKWOOL boards are installed within a cladding
attachment system, fastening requirements may vary based on the end-use
application. Fasteners should be numerous enough and of large enough cross
section to prevent tear-through of the insulation under expected conditions.
Fore more information, refer to ROCKWOOL’s Board Insulation Attachment Guide.
Impaling Pins Mechanically attached impaling pins are an acceptable attachment
method for plain board insulation. Adhesivebacked impaling pins can also be
considered for the permanent attachment of ROCKWOOL board insulation. In this
case, ROCKWOOL recommends seeking validation from the attachment and/or
adhesive manufacturer to determine if the impaling pins can adequately support
the insulation and that the adhesive is compatible with the substrate upon
which it will be adhered.
Adhesive Directly Applied to ROCKWOOL Boards ROCKWOOL does not recommend the
use of adhesives directly applied to ROCKWOOL board insulation for permanent
attachment. However, a construction grade adhesive can be used for the
temporary attachment of ROCKWOOL boards, before connections are installed for
permanent attachment. Construction grade adhesives must be compatible with
ROCKWOOL stone wool (mineral wool) boards and the intended substrate so that
the adhesive does not damage the substrate or negatively affect its
performance.
Selection of Fasteners or Impaling Pins Fasteners or impaling pins should be:
· Chosen in accordance with the substrate type,
· Capable of withstanding applied pull-out and shearloads,
· Sufficiently durable to withstand the environment to which they will be
exposed.
Fastener Depth Embedded fastener depth will vary based on substrate. As a
general rule, embed a minimum of 1.5″ deep in wood studs and concrete. Extend
at least 3 full threads past the flange of steel studs. Anti-unwinding
fasteners (or alternative precautions) should be used for metal frame
construction. The embedment should be validated with the fastener
manufacturer.
ROCKWOOL 27
Fastening Patterns for Plain Board Insulation
The dimension of the insulation boards dictates the minimum number of
attachments required and their fastening pattern. This section provides
examples for insulation boards up to 48″ in length installed over a solid wall
and a wood/metal stud wall. For more information refer to ROCKWOOL’s Board
Insulation Attachment Guide. Strapping fastening patterns for ROCKWOOL rigid
board insulation should be specified based on the backup assembly and project
specific loads (weight of cladding). Long screw fasteners must penetrate
framing members like studs and this effects the potential horizontal spacing
of the fasteners and strapping. For additional guidance on the installation
and information on the performance of ROCKWOOL rigid board insulation with
strapping, please refer to Comfortboard® 80 Installation Guide and Performance
of Strapping Attachment on Walls with Long Screws Through ROCKWOOL Rigid
Insulation.
Disclaimer and Limitation of Liability Fastening connections should be
designed to withstand all the combined applied loads, including but not
limited to dead-load and wind-load. Where applicable, consideration should be
given to seismic-load, and live-load (not covered in this guide). Failure to
include safety factors or adequately design for applied loads can result in
failure of mechanical attachment. The determination of the specific design
requirements and safety factors regarding a fastener system is the sole
responsibility of the installer and/or end user. ROCKWOOL Inc assumes no
responsibility whatsoever for any failure of insulation attachment or related
fastening systems. The statements and data contained in this document are for
general information purposes ONLY. They are NOT specific technical
recommendations as to any particular design or application and the ultimate
determination as to product suitability is the sole responsibility of the
installer or end user. Although the information contained herein, including
ROCKWOOL product descriptions, is believed to be correct at the time of
publication, accuracy cannot be guaranteed and results may vary depending on
the particular design and/or application. ROCKWOOL fully reserves the right to
make product specification changes, without notice or obligation, and to
modify or discontinue any of its products at any time. In no event, shall
ROCKWOOL be liable for any direct, indirect, or consequential damages of any
kind arising from information contained in this bulletin, including, but not
limited to, claims for loss of profits, business interruption, or damages to
business reputation. This limitation of liability shall apply to all claims
whether those claims are based in contract, tort, or any legal cause of
action. When penetrating or adhering to a water-resistive barrier (WRB),
ROCKWOOL recommends referring to the attachment and membrane manufacturers to
secure additional direction on installation method and material compatibility.
As ROCKWOOL does not supply fasteners or adhesives, it is the responsibility
of the manufacturers of the fastenings or adhesives to comment on the
performance of their products when managing the loads of ROCKWOOL insulation
materials and other assembly components. ROCKWOOL makes no representations or
warranties, express or implied, with respect to its recommendations for
attaching the semirigid and rigid board products with fastenings and all
warranties are disclaimed.
ROCKWOOL 28
At the ROCKWOOL Group, we are committed to enriching the lives of everyone who
comes into contact with our solutions. Our expertise is perfectly suited to
tackle many of today’s smallest sustainability and development challenges,
from energy consumption and noise pollution to fire resilience, water scarcity
and flooding. Our range of products reflects the diversity of the world’s
needs, while supporting our stakeholders in reducing their own carbon
footprint. Stone wool is a versatile material and forms the basis of all our
businesses. With more than 12,000 employees in 40 countries, we are the world
leader in stone wool solutions, from building insulation to acoustic ceilings,
external cladding systems to horticultural solutions, engineered fibres for
industrial use to insulation for the process industry and marine and offshore.
AFB®, Cavityrock®, Comfortbatt®, Comfortboard®, Conrock®, Curtainrock®, ROXUL
Safe®, Rockboard®, Toprock®, Monoboard®, ROXUL® are registered trademarks of
the ROCKWOOL Group in USA and ROXUL Inc. in Canada. ROCKWOOLTM, FabrockTM,
FrontrockTM and MultifixTM are trademarks of the ROCKWOOL Group in USA and
ROXUL Inc. in Canada. SAFE’n’SOUND® is a registered trademark used under
license by Masonite Inc.
ROCK2W9 OOL
ROCKWOOL
8024 Esquesing Line Milton, ON L9T 6W3 Tel: 1 800 265 6878
rockwool.com
Publication date – edition: 02/2023