Start with the opening drawing note of the issued Section 04 23 00: confirm that every glass block panel has head, jamb, sill, and intermediate support details and that the clearances for deflection of the structure above and for panel expansion are drawn. Then check that the unit type, pattern, size, and light transmission on the elevations are the ones kept in the section, that panels in rated walls are listed assemblies within their listed size, that the details choose panel anchors or channels at each head and jamb, that joint reinforcement, expansion joints, and sealant are shown where the section puts them, and that the section’s disagreeing metric and inch-pound values and sealant timing are corrected before submittals arrive.
Assemble the review package
Gather the floor plans and the exterior and interior elevations with each glass block panel and its size, the wall sections and the head, jamb, sill, and intermediate stiffener details, the structural drawings with the beams or slabs above each panel and their expected deflection, the design wind or interior lateral load, the life safety plan and wall types showing which walls are rated, the window or opening schedule if panels are tagged there, the lighting, privacy, and appearance intent for pattern, light transmission, and reflective units, the joint sealant schedule, the design analysis with the climate and corrosion exposure, and the issued Section 04 23 00 with Section 07 92 00, the project’s unit masonry, window, and glazing sections, and the manufacturer’s panel size and anchorage data. Follow one exterior panel and one panel in a rated wall from sill to head before assuming the others match.
WBDG publishes UFGS 04 23 00: Glass Unit Masonry 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 (head, jamb, sill, and intermediate support details; clearances for deflection and expansion; panel size limits from the manufacturer’s data and the TMS MSJC) + Expansion Joints (the space indicated, free of mortar) + Lateral Support General (anchorage that leaves the construction above free to deflect) + elevations, sections, and details + structural framing above each panel | Does every panel on the elevations trace to a head, jamb, and sill detail, are intermediate stiffeners or supports drawn wherever a panel is larger than the manufacturer’s data allows without them, is the expansion space at the head and jambs dimensioned, since the section only asks for the space indicated, and does the head clearance suit the deflection the structural drawings expect at that beam or slab? |
| Unit type, pattern, size, and light transmission | Manufactured Units note (describe light transmittance, reflectivity, pattern, and size; says the most common patterns are listed by name; thin hollow units not covered) + Glass Masonry Units (types, size, pattern, and style indicated; one source of supply; extra stock bracket; edge coating) + Standard Hollow and Thin Solid articles (pattern blanks, fibrous glass insert bracket, size brackets, reflective coating, light transmission brackets) + elevations and finish or opening schedule | Do the elevations or a schedule give each panel’s unit type, pattern, size, and any insert or reflective option, are the pattern and light transmission blanks filled to match the drawings and the lighting or privacy intent, since the note says patterns are listed but the hollow unit article names none, are thin hollow units, which the note excludes, kept off the drawings, and does the extra stock bracket suit a project with several patterns? |
| Fire-rated glass block | Fire Rated Glass Masonry Units note (glass block rated for fire protection, not fire resistance; panel size limits by rating; listing and testing under NFPA 80, UL 9, and NFPA 257) and article (listed units tested to the indicated rating where rated walls contain glass block windows) + SD-07 Certificates + life safety plan and wall types + the project’s rated opening and glazing sections | Is every panel in a rated wall marked with the rating it needs, is that wall one where a fire-protection-rated opening is permitted rather than a wall that must keep its fire-resistance rating across the panel, does each rated panel fall within the size its listing allows, and since no submittal asks for the listing or label, how will the contracting officer confirm the units installed are the listed ones? |
| Mortar and water repellent | Mortar (ASTM C270 Type S or N with white cementitious materials) + Mortar note (water repellent when the panel is exposed to the exterior) + Water Repellent Additive or Admixture article (not bracketed; required unless already in the cement) + Admixtures (only with approval) + Mortar Mixing (reduced water; machine mixing) + Mortar Preparation (discard time printed as a range that reads as a misprint) + SD-03 and SD-07 + elevations | Where a panel is interior, should the water repellent paragraph, which the note ties to exterior exposure but the article requires in every panel, be bracketed or deleted, does the mortar color and type agree with any adjacent masonry the panel sits in, and has the specifier corrected the discard time in Mortar Preparation before the contractor’s quality control relies on it? |
| Joint reinforcement and mortar joints | Joint Reinforcement product article (ASTM A951 wire hot-dip zinc coated or stainless; wire size brackets whose metric and inch-pound diameters describe different wires; wire spacing by unit type; flat lengths) + Mortar Joints (width by unit type; full joints; reinforcing centered in the joint) + Joint Reinforcement installation (spacing; continuous except at expansion joints; added courses at openings within the panel; laps) + Mortar Joint Tooling + panel elevations and details | Do the panel elevations or details show joint reinforcement courses and the extra courses above and below any opening within a panel, is stainless wire chosen where the panel is exterior in a corrosive location, has the specifier kept one wire size and corrected its conversion, since the metric and inch-pound options are different wires, and is reinforcement stopped at expansion joints rather than carried across them? |
| Lateral support: panel anchors or channels | Perimeter Anchorage note (top and sides supported by panel anchors or channel restraints; channels oversized for expansion material, packing, and sealant; supports designed for the applied load or a TMS MSJC minimum whose metric and inch-pound values disagree) + Panel Anchors product (galvanized or stainless strip; fastener capacity blank) and execution (spacing at jambs and heads; embedment; fasteners per anchor) + Channel-Type Anchorage (aluminum channels by unit type, one with disagreeing metric and inch-pound dimensions; bituminous coating at dissimilar metals) + structural lateral load | Do the head and jamb details choose panel anchors or channels for each panel rather than leaving the choice to the contractor, is the fastener capacity blank filled from the lateral load the engineer of record determined, since the note’s minimum is stated in values that disagree, is the channel called out one whose dimensions are stated consistently, and do aluminum channels that touch steel or concrete show the coating the section requires? |
| Expansion joints, sill, and sealant | Expansion Strip (closed-cell polyethylene or sponge rubber) + Asphalt Emulsion and Preparation (a heavy coat on the sill; metal and porous surface types) + Expansion Joints (head, jambs, and intermediate supports free of mortar) + Sealing of Expansion Joints (sealant and backer rod per Section 07 92 00 after a waiting period following curing) + Sequencing and Scheduling (sealant immediately after the mortar reaches final set) + Section 07 92 00 + head, jamb, and sill details | Do the details show expansion strip at the jambs and head, asphalt emulsion on the sill, and sealant and backer rod on both faces at the head, jambs, and intermediate supports, is that sealant named in the joint sealant schedule, and since Sequencing and Scheduling calls for sealant immediately after final set while Sealing of Expansion Joints requires a wait after curing, which timing governs the schedule? |
| Cold weather, installation, repair, and cleaning | Project/Site Conditions (cold weather limits; a protection temperature range whose upper metric and inch-pound values disagree; both sides of the panel kept warm after erection; tops covered) + Delivery, Storage, and Handling + Glass Masonry Unit Installation (no steel tools; stacked bond bracket; units not moved once placed) + Tolerances (TMS MSJC site tolerances) + Repair of Defective Work + Cleaning (no abrasive cleaners or acids) + schedule and phasing | If panels will be laid in cold weather, does the schedule allow enclosure and heat on both sides of each panel, has the specifier corrected the upper protection temperature, is any bond other than stacked bond drawn and written into the bracket, and are the cleaning methods for adjacent masonry or concrete kept away from the glass faces, since the section prohibits abrasives and acids on them? |
Worked example: an exterior panel with no head detail and a corridor panel with no rating
Illustrative example: a renovated fitness center at an installation adds two glass block panels to an exterior masonry wall and one panel in a rated corridor wall beside the locker room. The elevations show the panels and a pattern name, but the details show only a sill; there is no head detail under the steel beam above, whose deflection is noted on the structural drawings, and no stiffener in the larger exterior panel. The life safety plan shows the corridor wall as rated, but the panel in it carries no rating. The issued Section 04 23 00 keeps both the panel anchor and channel paragraphs, leaves the fastener capacity blank empty, keeps the water repellent article for every panel, and keeps both sealant timing paragraphs and the disagreeing metric and inch-pound values as printed.
Ask the architect to draw head and jamb details that choose anchors or channels and show the deflection clearance, expansion strip, and sealant, to add a stiffener or split the larger panel where the manufacturer’s data requires it, and to mark the rating of the corridor panel or replace it with a rated assembly the wall allows. Ask the structural engineer for the lateral load the fasteners must resist. Ask the specifier to fill in the fastener capacity, keep the water repellent for exterior panels only, pick one sealant timing, add a submittal for the fire listing, and correct the wire size, channel, lateral load, temperature, and discard time values, and confirm the corrected values with the manufacturer’s data.
Avoid a false conflict
Section 04 23 00 covers glass block panels laid in mortar. The sealant and backer rod follow Section 07 92 00 and the joint sealant guide, the masonry around a panel follows the project’s unit masonry section and the masonry guide, windows and rated glazing other than glass block follow their own sections and the window and glazing guides, and the fire test and listing questions are covered in the NFPA 257 and NFPA 80 guides, so check those before calling a requirement missing. Some of the section’s own wording needs resolving: Sequencing and Scheduling and Sealing of Expansion Joints set different times for the sealant, the water repellent is required everywhere though its note ties it to exterior panels, the units note says patterns are listed by name though the hollow unit article names none, and the lateral load in the anchorage note, one joint reinforcement wire size, one channel size, and the upper protection temperature are each stated in metric and inch-pound values that disagree, while the mortar discard time is printed as a range that reads as a misprint. 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.