Spray foam under crawl space

Just did the worse new construction inspection (punch list) I’ve ever done. This question is about spray foam under crawl space. We don’t have this application in the part of Texas I work in. There is about three to four inches of the foam sprayed on TGI beams without any vapor barrier installed. The ream is not completely sprayed and the crawl space is ventilated well. Does the 3/4 in subfloor and then the 1/2 inch wood flooring meet the fire code for spray foam under a crawl space?

You really should get the spec/data sheet from the manufacturer…you can go here to find out the the IRC has to say.

It’s TJI’s are a name brand, use the word I-joist in your report unless you now the specific brand.

Hope this helps


Jeffrey I do agree and as for the application if there is any smell than it means they have applied it wrong. There is a good article about spray foam insulation done by Trish Holder and you can read about it at www.greenspirationhome.com

“2009 IRC N1101.4 Building thermal envelope insulation. An R-value
identification mark shall be applied by the manufacturer to
each piece of building thermal envelope insulation 12 inches
(305 mm) or more wide. Alternately, the insulation installers
shall provide a certification listing the type, manufacturer and
R-value of insulation installed in each element of the building
thermal envelope. For blown or sprayed insulation (fiberglass
and cellulose), the initial installed thickness, settled thickness,
settled R-value, installed density, coverage area and number of
bags installed shall be listed on the certification. For sprayed
polyurethane foam (SPF) insulation, the installed thickness of
the area covered and R-value of installed thickness shall be
listed on the certificate. The insulation installer shall sign, date
and post the certificate in a conspicuous location on the job site

Read R316.5.4 below. That’s probably why I’ve never seen foam insulation in a crawl space. It is a burdensome requirement.

“2009 IRC R316.4 Thermal barrier. Unless otherwise allowed in Section
R316.5 or Section R316.6, foam plastic shall be separated from
the interior of a building by an approved thermal barrier of minimum
1/2 inch (12.7 mm) gypsum wallboard or an approved finish
material equivalent to a thermal barrier material that will
limit the average temperature rise of the unexposed surface to
no more than 250°F (139°C) after 15 minutes of fire exposure
complying with the ASTME 119 orUL263 standard time temperature
curve. The thermal barrier shall be installed in such a
manner that it will remain in place for 15 minutes based on
NFPA 286 with the acceptance criteria of Section R302.9.4,
FM 4880, UL 1040 or UL 1715.”

Code Commentary: The use of an approved thermal barrier to separate
foam plastics from the interior of a building is a basic
requirement for the use of foam plastic as shown in
this section of the code. The job of a thermal barrier is
to isolate the foam plastic. An approved thermal barrier
is defined as minimum 1/2-inch (12.7 mm) gypsum
wallboard or the equivalent. This section sets forth the
test methods and performance criteria by which alternative
thermal barriers are to be qualified [limiting the
average temperature rise of the unexposed face to
250°F (121°C) for 15 minutes of fire exposure, while
complying with the time-temperature conditions of
ASTM E 119 or UL 263]. The thermal barrier must be
installed so that it remains in place for 15 minutes
when exposed to fire.

Sections R316.5 and R316.6 describe circumstances
where the requirement for a thermal barrier is
modified or eliminated.

Before 1975, experience had shown that foam plastics
covered with plaster or 1/2-inch (12.7 mm) gypsum
wallboard had performed satisfactorily in building fires.
For this reason, 1/2-inch (12.7 mm) gypsum wallboard
was included in the code as a minimum requirement. It
was recognized that specifying a single material would
not be desirable in a performance code; therefore, the
words “or equivalent” were added. The thermal barrier
test was selected as the appropriate method to determine
equivalent performance. Although regular
1/2-inch (12.7 mm) gypsum wallboard happened to
have a 15-minute rating in the prescribed thermal barrier
test, there was no intent that the 15-minute re-
requirement for the thermal barrier would ensure 15 min-
utes of escape time in an actual building fire. This is
related to the fact that the time-temperature conditions
of ASTM E 119 or UL 263 may not reflect actual fire
conditions. Gypsum wallboard is still the most commonly
used thermal barrier, but equivalent materials
are permitted and have been used when shown to be

“2009 IRC R316.5.4 Crawl spaces. **The thermal barrier specified in Section R316.4 is not required **where all of the following apply: 1. Crawlspace access is required by Section R408.4
2. Entry is made only for purposes of repairs or maintenance.
3. **The foam plastic insulation is protected against ignition
using one of the following ignition barrier materials:
** [INDENT]3.1. 11/2-inch-thick (38 mm)mineral fiber insulation;
3.2. 1/4-inch-thick (6.4 mm) wood structural panels;
3.3. 3/8-inch (9.5 mm) particleboard;
3.4. 1/4-inch (6.4 mm) hardboard;
3.5. 3/8-inch (9.5 mm) gypsum board; or
3.6. Corrosion-resistant steel having a base metal
thickness of 0.016 inch (0.406 mm).

[/INDENT]The above ignition barrier is not required where the foam
plastic insulation has been tested in accordance with Section

Code Commentary: In a crawl space where access is required by Section
R408.4 (access shall be provided to all under-floor
spaces) and entry is only for service of utilities, and
when foam plastics are used, an ignition barrier may
be used in place of a thermal barrier to cover the foam
plastic. Multiple materials are listed that can be used
as the ignition barrier (see Commentary Figure
R316.5.3). The foam plastic material, covered with the
ignition barrier can be on the floor, wall or ceiling of the
crawl space. The phrase “purposes of repairs or maintenance”
applies to crawl spaces that contain only mechanical
equipment, electrical wiring, fans, plumbing,
gas, or electric hot water heaters, gas or electric furnaces,
etc. The crawl space cannot be used for storage.
The reduced requirement (from a thermal barrier
to an ignition barrier) provides a barrier whose only
purpose is to prevent the direct impingement of flame
on the foam plastic.

If the foam plastic insulation has passed testing, in
the thickness and density intended for use, in accordance
with Section R316.6, no thermal barrier or ignition
barrier is required over the foam plastic insulation
in the crawl space and this section of the code does
not apply. It is important to note that the actual configuration
must be tested. For example, a foam plastic insulation
applied to the ceiling of the crawl space must
be tested with the foam applied to the ceiling in a room
corner test or in an assembly that reflects end use
. The
same restrictions would apply to those insulations applied
to the walls, floors or combinations of surfaces.

"2009 IRC R316.6 Specific approval. Foam plastic not meeting the
requirements of Sections R316.3 through R316.5 shall be specifically
approved on the basis of one of the following
approved tests: NFPA 286 with the acceptance criteria of Section
R302.9.4, FM4880, UL 723, UL 1040 or UL 1715, or fire
tests related to actual end-use configurations. The specific
approval shall be based on the actual end use configuration and
shall be performed on the finished foam plastic assembly in the
maximum thickness intended for use. Assemblies tested shall
include seams, joints and other typical details used in the installation
of the assembly and shall be tested in the manner
intended for use.

Code Commentary: Foam plastic does not have to comply with the installation
and use requirements of Sections R316.3 through
R316.5 when specific approval is obtained in accordance
with this section. This section lists examples of
specific large scale tests, such as FM 4880, NFPA
286, UL 723, UL 1040 or UL 1715. Also, other large
scale fire tests related to actual end-use configuration
can be used. The intent is to require testing based on
the proposed end-use configuration of the foam plastic
assembly with a fire exposure that is appropriate in
size and location for the proposed application. These
tests must be performed on full-scale assemblies. The
tested assemblies must include typical seams, joints
and other details that will occur in the finished installation.
The foam plastic must be tested in the maximum
thickness and density intended for use. Thorough testing
provides an accurate depiction of the in-place fire
performance of assemblies and systems using foam

There are two ways to show code compliance under
Section R316.6. One method is to provide the actual
test report that contains a description of the assembly
and test results showing that the foam plastic, in the
end use application, has passed the test. The second
method is to obtain, from the ICC-ES, an evaluation report
that covers the end-use application."

Thanks everyone for the great answers, I will print and pass and call the problems out to the owner.