Signs you need this
- • A life-safety drawing set for an industrial or institutional building, such as a facility near GE River Works on the Lynnway or a corridor at North Shore Community College, calling out a one-hour or two-hour rated partition or shaft wall by UL assembly number.
- • An existing fire-rated wall that's been penetrated for new conduit, cable tray, or ductwork without the penetration being properly fire-stopped and restored to the listed assembly.
- • A code inspection on an industrial or institutional building flagging a wall or shaft that no longer matches its as-built rated assembly.
Lynn Drywall & Plaster builds and restores fire-rated drywall assemblies to their specific UL listing, including rated partitions, shaft walls, and corridor separations at one-hour and two-hour ratings. This is not general Type X board work; each assembly is built to a numbered UL design that specifies board layers, fastener spacing, framing type, and any required insulation, and any penetration through it has to be fire-stopped to a listed method to keep the rating intact. On industrial and institutional buildings along the Lynnway and downtown, Lynn Drywall & Plaster documents the assembly and listing number for the owner’s life-safety file and any inspector review.
This service is for general contractors and facilities managers on industrial and institutional projects along the Lynnway corridor, where GE River Works anchors the district’s industrial base and fire-rated separations are a standing code requirement, and for building owners and facilities teams at institutional properties, including educational and healthcare-adjacent buildings, maintaining shaft walls and corridor separations to their listed rating. It also fits mechanical, electrical, and plumbing contractors whose work penetrates an existing rated wall and needs the assembly restored afterward, and code officials and building owners responding to a failed fire and life-safety inspection.
A UL listing is a whole system, not a type of board
The most common misunderstanding on a rated wall is that Type X board is what makes it fire-rated. It is not. The rating belongs to a specific numbered UL assembly that spells out the stud type and spacing, the exact number of board layers, the fastener pattern and length, the joint treatment, and any insulation, all tested together to hold a fire for one hour or two. Change any one element, a second layer left off, a wider screw spacing, a substituted stud, and the rating no longer applies, even though the wall still looks finished. Lynn Drywall & Plaster builds to the numbered design on the life-safety drawing set for industrial and institutional buildings along the Lynnway corridor near GE River Works and at institutional properties like North Shore Community College, and does not simplify the assembly to save a step.
Penetration restoration is where ratings quietly fail
The rated walls in an occupied building rarely fail because they were built wrong. They fail because someone opened them later. An electrician runs new conduit, a low-voltage contractor pulls cable tray, an HVAC crew cores through for a duct, and the hole gets left open or stuffed with the wrong material. Now the wall carries a breach that voids its rating, and it usually stays hidden until a periodic fire and life-safety inspection turns it up. Restoring it means sealing the penetration with a firestop method listed for that specific penetrating item and patching the assembly back to its original design, not just filling the gap with whatever is on the truck.
The documentation is part of the deliverable
On a rated assembly, the paperwork matters as much as the board. Lynn Drywall & Plaster records the completed wall against its UL design number, layer count, and fastening detail and hands it over for the owner’s or facility’s life-safety file, so the next inspector or design team can see what the wall is rather than having to guess from a core sample. On a restoration where the original listing was never recorded, the crew identifies the likely assembly from the existing board layers and framing on site and documents it going forward.
Working around an occupied building
Industrial and institutional buildings rarely shut down for this work, so phased sequencing around operating hours is routine, and it fits penetration restoration especially well because only a section of wall is open at any one time. The value to the owner is a building whose rated separations actually match their drawings, an inspection that passes on the documentation instead of a re-inspection, and a wall that will do its one job on the day it is needed.
Materials & standards
Products & materials we use
- USG
- National Gypsum Gold Bond
- Type X
- DensGlass
Standards & codes we work to
- UL fire-rated assemblies
- Massachusetts State Building Code (780 CMR, IBC-based)
- ICC/IBC
What the terms mean
- UL design number
- shaft wall
- CH-stud
- fire-stopping
- rated partition
- one-hour rating
- two-hour rating
- listed assembly
Options & variants
| Option | When it applies | Cost |
|---|---|---|
| One-hour rated partition | Standard tenant or corridor separation in commercial or institutional buildings | — |
| Two-hour rated partition | Higher-hazard separations, often industrial or shaft-adjacent walls | — |
| Shaft wall installation | Elevator shafts, mechanical chases, and stairwell enclosures | — |
| Penetration restoration | Existing rated wall opened for new conduit, cable, or ductwork | — |
What to expect
- 1
Confirm the UL design number
Lynn Drywall & Plaster confirms the required UL assembly number from the drawing set or, on a restoration, identifies the assembly the existing wall was originally built to.
- 2
Verify or build framing to the listing
Framing is verified or built to match the listing's stud type and spacing.
- 3
Install board to the exact design
Board is installed in the exact layer count and fastening pattern the UL design specifies, since a rated assembly can't be substituted or simplified without voiding the rating.
- 4
Fire-stop penetrations
Any penetrations for mechanical, electrical, or plumbing work are sealed with a listed fire-stopping method matched to the penetrating item.
- 5
Document the listing
The completed assembly is documented with its listing number for the owner's or facility's life-safety file and any code inspection.
When this isn’t the right call
- If the wall or partition being built has no fire-rating requirement in the drawings, that is standard commercial metal stud framing and board work, not an assembly build.
- If the project is a residential garage-to-house fire separation rather than a commercial or industrial rated assembly, that is the residential garage fire-separation service, which follows a different code path.
- If the scope is only the steel framing layout with no board or listed assembly involved yet, that is the metal stud framing scope, priced separately from the completed rated assembly.
Frequently asked questions
Can you match an existing rated assembly if we don't know its original UL number? +
Lynn Drywall & Plaster can identify the likely assembly from the board layers and framing type on site, and will document it going forward, though matching an unrecorded original listing exactly sometimes requires the design team's input.
Do you fire-stop penetrations, or is that a separate trade? +
Lynn Drywall & Plaster fire-stops penetrations that occur as part of the drywall assembly scope. Larger mechanical penetrations coordinated by another trade are fire-stopped to the same listed standard, coordinated with that trade.
What is the difference between a rated partition and a shaft wall? +
A rated partition is a standard wall built to a fire-resistance rating. A shaft wall is a specific system, typically CH-stud based, built for elevator shafts, stairwells, and mechanical chases, with its own listed assembly.
How do you document the assembly for our inspector? +
The completed wall is recorded against its UL design number, board layer count, and fastening detail, handed over for the facility's life-safety file.
Can this work be done in an occupied building? +
Yes, phased work around an occupied industrial or institutional schedule is common, particularly for penetration restoration where only a section of wall is affected at a time.
Do you handle both one-hour and two-hour rated assemblies? +
Yes, both are built to their respective UL listing, with the two-hour assembly typically requiring additional board layers per the design.