CPA Insulation Inspection
Page 1 of 3
INSULATION
Building Division
City of Palo Alto
Building Inspection Division
285 Hamilton Ave.
Inspection Request: 650 329-2496
IVR# 235
Revision Date:1/18/11
General Requirements/Checklist for:
Residential
Codes Enforced:
2010 CRC
Palo Alto Municipal Code (PAMC)
The information provided in this document is general and intended as a guide only. Each project is unique and additional
requirements may be enforced as deemed appropriate.
WARNING
 Insulation inspection certification of insulation from installers is not acceptable. (no exceptions)
 Failure to complete items below, prior to inspection, may result in a re-inspection fee.
 Construction hour’s sign and address shall be posted on all job site prior to inspection.
 Gas/Electric utilities will be removed if found to be unsafe at time of inspection.
ALERNATE MATERIALS
 Alternate methods and materials shall be submitted/ CPA approved prior to installation
(i.e. blown-in, Loose-fill, and spray foam insulation.)
PRIOR TO INSPECTION
 Verify all required sequential inspections and correction notices are complete.
DOUBLE SIDED SHEARWALLS
 Double sided shear walls should be inspected at this time.
FIRE& SMOKE INDEX
 Concealed insulating materials shall have a flame spread index of not more than 25 and a smokedeveloped index of not more than 450. CRC R302.10.1
NOT ALLOWED
 Paper faced insulation is not permitted in attics, the open side of furred spaces, and ventilated
interstitial spaces due to the potential of embers igniting the paper. Quilted foil-backed or unfaced fiberglass batts and blankets are better suited to conditions of potential fire hazards.
 Use approved quilted foil-backed insulation such as “Reflectix Insulation” in areas where a vapor
barrier is required and use as a fix when paper back insulation is exposed.
CPA Insulation Inspection
Page 2 of 3
Frequently Missed/Inspection failures
 INSPECTION
 Verify insulation requirements on T-24 page of plans. R-Value insulation and U-Factor windows
and skylights. See “Title-24 Energy” Checklist.
 Air space for cathedral ceiling ventilation: Provide minimum 1” air space between insulation
and roof sheathing CRC R806.3 see FIGURE A-1
 Baffles shall be installed as required to provide free passage of air at eave and ridge vents
 Shields: Verify that insulation shields are installed around gas appliance vents.
 IC-Rated recessed lights shall be covered with insulation.
 Compression: Verify that insulation is not compressed or buckled and is flush and fully
expanded with framing members.
 Penetrations: Foam insulate all penetrations at floor, floor to ceiling and ceiling to attic
locations.
 Tub and shower traps shall be fire blocked/sealed.
 Direct Contact: Verify that insulation is flush and fully expanded with framing members.
(Insulation must have contact with drywall, floor and ceiling), fills cavity.
 Access covers: Under-floor access cover= rigid R-19 insulation. Attic access cover= R-30. Access
doors shall be installed with weather stripping or gasket.
 Attic platform shall be fully insulated with required R-value.
 Framing: Verify all window jams, doors and rough openings are sealed.
 Furred spaces such as skylight chases and chimneys shall be supported at open side with plastic
or metal straps not more than 12” on center. (Paper faced bats not allowed on open side of
furred spaces.)
 Draft stops shall be in place.
 Top plates at attic and floor shall be covered with insulation.
 Cathedral ceiling ventilation
See FIGURE A-1
 Net free ventilating area shall not be less than 1/150 of the space ventilated. R806.2
Exception: spray foam insulation
 Enclosed rafter spaces shall have cross ventilation for each separate space.
 Provide 50 % of the required ventilating area at the upper portion of the space and the balance at
the eave/lower area of the space. R806.2
 A minimum 1” airspace is required between insulation and roof sheathing. R806.3
 Unvented attic assemblies R806.4
 Unvented attic assemblies (spaces between the ceiling joist of the top story and the roof rafters)
shall be permitted if all the following methods and conditions are met:
1. Air-impermeable insulation only - air-impermeable insulation shall be applied in direct contact to the
underside of the structural roof sheathing.
2. Air-permeable insulation only - in addition to the air-permeable insulation installed directly below the
structural sheathing, rigid board or sheet insulation with an R-value of R-4 shall be installed directly above
the structural roof sheathing as specified in Table 1 for condensation control.
3. Air-impermeable and air-permeable insulation - air-impermeable insulation shall be applied in direct
contact to the underside of the structural roof sheathing as specified in Table 1 for condensation control.
The air-permeable insulation shall be installed directly under the air-impermeable insulation.
 Note: Examples of “air-impermeable” insulation include polyurethane spray foam and extruded
polystyrene rigid foam. The following are not air-impermeable: fiberglass, rock wool and
netted or blown cellulose insulation.
CPA Insulation Inspection
 FOUNDATION, SLAB, BASEMENT (if applicable)
 Verify slab-edge insulation R-Value.
 Verify below-grade wall insulation R-Value.
 Radiant heat slab, verify wall insulation and slab edge insulation, if required.
 WINDOWS AND DOORS
 All windows, skylights, and doors meet U-value per plans.
 TUB TEST (fill tubs prior to inspection)
 Tub test: Fill water slightly above overflow.
FIGURE A-1
EXAMPLE OF RIDGE VENTILATION
Page 3 of 3