Start with the opening drawing note of the issued Section 07 21 23: confirm that the drawings show each location to be filled with its R-value, the vapor retarder location where one is required, and the size and location of attic ventilation openings. Then check that the fill material suits the dampness of each location, that the R-value is stated as a settled value with the depth and weight per area to verify it, that eave vents, attic doors, recessed lights, and flues are blocked or cleared in the details, that existing walls to be filled have a survey of fire blocking and duct cavities, that granular fill appears only in masonry, and that the bracketing kept still includes the wall paragraphs the project needs.
Assemble the review package
Gather the building and wall sections through attics, ceilings, and framed walls with the R-value and the depth of fill drawn, the eave and soffit details with baffles and blocking, the roof plan with the attic vent sizes and counts, the reflected ceiling plans with recessed light fixtures, attic hatches, and access panels, the mechanical plans with ductwork, air handlers, returns, and any stud or joist cavities used as ducts, the flue, chimney, and appliance locations, the masonry wall sections and CMU core fill notes, the existing conditions survey for retrofit work with moisture, mold, electrical, and fire blocking findings, the energy compliance documents and the moisture analysis, and the issued Section 07 21 23 with Sections 07 21 16, 04 20 00, 07 27 10, 09 29 00, and the HVAC and electrical sections. Follow one attic and one existing wall from the eave or entry hole to the finished depth before assuming the others match.
WBDG publishes UFGS 07 21 23: Loose Fill Thermal Insulation as a public guide-specification reference (accessed November 12, 2026). Use your project’s issued specification and amendments for the actual comparison; the guide specification does not automatically govern your project. The checklist below is an original suggested review workflow, not a reproduction of the UFGS requirements.
Eight checks to run against the issued set
Use one record per location or system. The CSV contains the same eight prompts plus fields for source revisions, observed evidence, the review owner, the decision, and closure references.
| Check | Sources to compare | Question to resolve |
|---|---|---|
| What the drawings must show | Opening drawing note (insulated locations, R-value at each, vapor retarder location, attic ventilation openings) + R-value note and sentence (as indicated on the drawings; the value achieved after settlement) + Attic Ventilation note (net ventilation by attic floor area, with or without a vapor retarder) + building and wall sections + roof plan | Does every attic, ceiling, framed wall, and masonry wall to be filled carry an R-value on the drawings, stated or noted as the settled value the article requires, is the vapor retarder shown wherever the project requires one, and does the roof plan size and locate the attic vents, given whether the ceiling has a vapor retarder? |
| Material by location and dampness | Loose Fill Insulation note (cellulose absorbs more moisture than mineral fiber; mineral fiber for damp locations; vermiculite or perlite only for masonry cavities and block cores) + items a to c (mineral fiber, pneumatic or poured, by category; cellulosic or wood fiber to ASTM C739 or 16 CFR 1209; granular vermiculite or perlite) + Fire Safety note + Prohibited Materials + sections and the existing conditions survey | Has the specifier kept only the materials the drawings use and tied each to a location, is cellulose kept out of damp attics, crawl spaces, and walls the survey shows have leaked, is granular fill limited to masonry cores and cavities, and since the cellulose item accepts either the ASTM product specification or the federal interim safety standard, which one must the product meet? |
| Settled R-value, depth, and coverage by weight | R-value sentence (achieved after settlement) + Delivery (bag labels with method, minimum net weight, coverage chart, R-value; cellulose safety and cautionary labels) + Insulation paragraph and note (ASTM C1015; no tamping or rodding; bracketed sentence on installing by weight per area, for mineral fiber and cellulose only) + Attics and Ceilings (fill to the specified R-value) + attic sections | Do the attic sections show the installed depth needed to reach the settled R-value for the material kept, is the weight-per-area sentence kept so the bag count can be checked against the coverage chart, and does the issued section ask for any record of depth or bag count, since the section requires a settled value but no article says how it is verified? |
| Attic ventilation, eave vents, and attic doors | Blocking at Attic Vents and Access Doors (permanent blocking so insulation does not cover or clog eave vents; bracketed blocking at attic trap doors and at equipment that needs maintenance) + Attics and Ceilings (lowest air pressure; do not blow into electrical devices or bracketed soffit and mechanical vents) + Special Requirements for Ceilings + Attic Ventilation note + eave details and roof plan | Do the eave details show a permanent baffle or dam tall enough to hold the settled depth back from the soffit vents and keep the air path open, is the attic hatch dammed and insulated, are walkways or dams drawn to keep fill away from attic equipment that needs service, and do the vent sizes on the roof plan match what the note asks for? |
| Clearances at recessed lights, chimneys, flues, and appliances | Blocking Around Heat Producing Devices items (recessed fixtures not rated for insulation contact; masonry chimneys; vents, connectors, and other chimneys to NFPA 211; gas appliances to NFPA 54; oil appliances to NFPA 31) + blocking exemption (insulation and retarder that pass ASTM E136, or chimneys listed for insulation contact) + Blocking article (noncombustible blocking) + existing conditions note (heat-producing devices; faulty wiring) + reflected ceiling plans and flue details | Are the recessed fixtures under blown attics scheduled as rated for insulation contact, or does the ceiling detail show noncombustible dams around them, do the flue and chimney penetrations through the attic floor show a dam or a listed product, does the exemption for noncombustible insulation apply to the material kept, since a combustible fill cannot rely on it, and has the retrofit survey of the existing wiring been done before fill covers it? |
| Filling existing frame walls | Frame Walls (fill cavities completely; bracketed exception for cavities that serve as HVAC ducts; entry holes; fire stops and obstructions; extra holes; close holes to match; bracketed sealing of holes through a vapor retarder) + Electrical Wiring + Cold Climate Requirement and note (insulation outside the pipes, by ASHRAE climate zone) + existing conditions survey + exterior elevations and siding or interior finish details | Does the survey or the drawings identify the fire blocking, headers, and stud or joist cavities used as return air paths in the walls to be filled, is the duct exception kept where those cavities exist, do the details say whether entry holes are drilled from outside or inside and how the siding or finish is patched, and in colder climate zones, is water piping in exterior walls on the warm side of the fill? |
| Granular fill in masonry walls, and how the section is bracketed | Masonry Walls (granular fill brought up in lifts as the wall is built; natural density) + item c (vermiculite or perlite) + Insulation paragraph (pneumatic equipment required, not bracketed) + numbering and brackets of [Attics] [and] [Ceilings] (Frame Walls, Masonry Walls, Electrical Wiring, Cold Climate, Ceilings, Sill Sealer, and Access Panels numbered under it and closed inside its bracket) + Section 04 20 00 and the masonry wall sections | Do the masonry wall sections and core fill notes in Section 04 20 00 agree on which cores are filled with insulation and which are grouted, is the lift height coordinated with the masonry sequence, since the insulation paragraph requires pneumatic equipment while granular fill is poured in lifts, which applies, and where the project has no attic or ceiling work, has the specifier kept the wall and wiring paragraphs that are numbered and bracketed inside the attic paragraph? |
| Vapor retarder, HVAC protection, and indoor air quality | Vapor Retarder notes (moisture analysis; warm-side placement in colder zones; avoid very low permeance interior retarders in warmer zones; foil-faced gypsum board as the alternative; combustible membranes not left exposed) + separate metric and inch-pound retarder lists (membrane permeance fixed in one, a choice in the other; Beach unit defined differently) + Pressure Sensitive Tape (metric value differs) + Installation of Vapor Retarder (not on both sides) + Protection of Ventilation System + Certifications (bracketed) and Reduced VOC paragraph and SD-07 item (not bracketed) | Do the sections show one retarder on the side the moisture analysis supports, and none where the analysis does not need one, is the permeance stated in one value that the retarder and tape both meet, since the metric and inch-pound lists and the tape paragraph disagree, has the existing ductwork been checked and sealed before blowing, and does the issued section require the indoor air certification only for a material for which certified products exist? |
Worked example: blowing cellulose into an attic over old downlights and into walls with duct cavities
Illustrative example: an energy retrofit of a barracks with a vented attic over a gypsum board ceiling adds blown cellulose to the attic and dense fill to the existing exterior frame walls. The attic section gives an R-value with no depth and no note that it is a settled value, the eave detail shows no baffle, and the existing downlights are not identified as rated for insulation contact; a gas water heater flue passes through the attic floor. The existing conditions survey notes past roof leaks at one wing and a panned return air cavity in a corridor wall, and does not mention fire blocking. The issued Section 07 21 23 keeps items a and b, keeps the frame walls paragraph without the duct exception, deletes the [Attics] [and] [Ceilings] bracket on the wall-only wing, and keeps the metric and inch-pound vapor retarder lists with a polyethylene retarder at the ceiling.
Ask the architect to state the settled depth for the material, add eave baffles, dams at the attic hatch, flue, and downlights unless the fixtures are replaced with rated ones, and to assign mineral fiber at the wing with past leaks. Ask the mechanical engineer to confirm which wall cavities carry air and to keep the duct exception, and ask the specifier to restore the frame wall paragraphs on the wall-only wing, to confirm with the moisture analysis whether the ceiling retarder is needed, and to state one permeance value for the retarder and tape.
Avoid a false conflict
Section 07 21 23 covers blown and poured mineral fiber, cellulose, and granular fill. Batts and blankets follow Section 07 21 16 and the blanket insulation guide, board and block insulation follows Section 07 21 13 and the wall insulation guide, roof insulation boards follow Section 07 22 00 and the roof insulation guide, masonry core grouting follows Section 04 20 00 and the masonry guide, the air barrier follows Section 07 27 10, and foil-faced gypsum board follows Section 09 29 00, so check those before calling a requirement missing. Some of the section’s own wording needs resolving: the Certifications article is bracketed while the VOC paragraph and its submittal are not, the metric and inch-pound vapor retarder lists differ in their membrane permeance and in their definition of the Beach unit, the tape gives a metric permeance that differs from the section’s other metric value for the same limit, the wall and wiring paragraphs sit inside the attic paragraph’s bracket, and the insulation paragraph requires pneumatic equipment while the section offers poured fill. Ask the specifier which wording the project intends before treating a difference as a design conflict.
When requirements disagree, follow the project’s document-control and clarification process. Do not assume that drawings always override specifications, or the reverse. Identify the exact sources and request an authorized decision.
Close the issue across the affected documents
Record the location or tag, drawing and specification references, issue dates, observed difference, and the decision needed. Assign an owner and keep the item open until the response identifies the governing requirement. Check the revised drawings and specification references together; a response email alone may leave the issued package inconsistent.
For the overall process, use the guide to drawing and specification conflicts. Mark an inapplicable checklist row with a reason, and distinguish a verified correction from a question that still needs design information.
Where Groundbook fits
Groundbook’s drawing and specification review helps investigate potential disagreements in the documents you supply. Include the relevant specification sections and drawing references, then verify the cited evidence with the responsible reviewers before acting on a finding.