What Is Flush Architrave Detailing? (Shadow Gaps)
Flush architrave detailing sets the door frame back so the wall appears to run cleanly to the opening, with a narrow, even shadow reveal instead of projecting trim. The reveal is a design choice, not a code-set size. Coordinate it with the finished wall, door system, hardware, accessibility needs, and any fire or smoke rating.
When updating a doorway, many homeowners want a cleaner wall line without creating a weak or uneven edge. Flush architrave detailing can achieve that look, but it depends on accurate planning behind the finish. A shadow gap that varies in width, or a frame set for the wrong wall depth, tends to stand out.
I treat this as a coordinated frame-and-wall detail, not a trim swap. Before work starts, identify the wall build-up, door type, profile system, and any code or listing limits. The steps below explain what to check and how to verify the finished result.
Plan the Reveal and Confirm the Wall Build-Up
A shadow gap is the open, recessed line between a door frame and the finished wall. Flush architrave detailing removes the usual projecting casing and uses a profile or frame detail to create this line. Its width and position are design choices that must suit the chosen system and the finished opening.
“Architrave” usually means the trim around a door. In a flush detail, that trim is absent or replaced by a recessed profile. The frame may sit behind the wall face, while a metal or timber edge profile gives the plasterboard or plaster a clean boundary.
There is no universal code dimension for the reveal width or jamb setback. A 10 mm reveal is a common interior design target, not a code minimum. Keep the target consistent at the head and both jambs unless the design or manufacturer calls for another detail.
Start with a survey:
- Identify the wall type and measure its finished build-up, including board, plaster, tile, or other finishes.
- Check the frame type, opening size, floor finish, and whether the opening is plumb and square.
- Locate nearby wiring, pipes, or other services before drilling or changing the frame.
- Confirm whether the door is fire-rated, smoke-controlled, or part of an accessible route.
- Select a shadow-gap profile that suits the wall and frame, and follow its installation instructions.
Measure the wall depth at several points. A frame sized only to the bare studs may sit too far in or out once finishes are added. Record the finished wall plane on both sides, since finishes may differ.
For a non-rated interior door, the leaf face can align with the wall face, or sit at a deliberate offset. Decide this before ordering the frame. Then check that the reveal profile, frame depth, hinge position, and door swing work together.
Check Door, Hardware, Accessibility, and Airflow Clearances
A flush frame still has to allow the door to swing, latch, and meet the opening’s required clearances. Plan the reveal around the full door assembly, not just the visible frame edge. Where accessibility or fire and smoke control apply, use the governing requirements and approved product details.
Check the door manufacturer’s limits for gaps, hinges, latches, seals, and any required clearances. Do not assume that a visually neat frame allows enough room for hardware or a full swing. Also check the approach and maneuvering space required by the applicable accessibility rules.
Avoid choosing a generic undercut, the gap between the door bottom and floor. The needed gap depends on the door, floor finish, and ventilation design. Confirm the door maker’s limits and ask the HVAC designer to verify any transfer-air need. A larger gap is not a substitute for that calculation.
For rated or smoke-control doors, preserve the listed assembly. The listing covers the approved door, frame, seals, hardware, and permitted clearances. Do not cut or route the door, add unapproved seals, or alter the bottom gap without approval for that exact assembly. Follow the adopted code, including applicable IBC Chapter 7 provisions and NFPA 80.
Install the Frame, Backing, and Shadow-Gap Profile
The profile needs a stable fixing surface so it stays straight and does not loosen as the wall is finished. Install continuous, rigid backing where the system requires it. Follow the selected manufacturer’s fixing method, screw spacing, edge distances, and compatible jointing materials.
Before closing the wall, set out the opening and frame position from the finished wall plane. Check the reveal at both jambs and the head, then verify the frame is plumb, level, and square. Small errors at this stage can become visible once the profile creates a crisp line.
A practical sequence is:
- Set out: Mark the finished wall plane, planned reveal, frame position, door swing, hardware, and skirting junctions.
- Provide backing: Fit solid, continuous support at the profile’s fixing points. Do not rely on drywall compound as a structural fixing.
- Fit the frame and profile: Use the specified sequence and fasteners. Keep the profile aligned with the frame and wall plane.
- Check before closing: Measure the reveal at several points and correct twists or movement before board or finish hides the fixings.
- Protect the edge: Keep joint compound and finish material out of the reveal as the wall is completed.
A useful project tolerance is no more than 3 mm of wall variation under a 2 m straightedge in the reveal zone. This is a proposed finish target, not a general code requirement. If the wall is outside the agreed tolerance, correct the substrate or agree on a suitable profile detail before finishing.
| Check | Typical project target or action | Important limit |
|---|---|---|
| Reveal width | 10 mm is a common interior design target | Not a code minimum; confirm the profile |
| Wall flatness at reveal | No more than 3 mm variation under a 2 m straightedge | Project tolerance, not a universal rule |
| Frame depth | Match the finished wall build-up | Include all finish layers |
| Profile fixing | Use the specified fasteners and spacing | Compound alone is not structural support |
| Door bottom gap | Verify with the door maker and HVAC design | No generic undercut suits every door |
Finish and Verify Alignment, Operation, and Compliance
Finishing should preserve the reveal rather than fill it. Use the tape, filler, and finish materials specified for the profile. After the finish cures, inspect the line in good light and test the door. A clean shadow is only successful if the frame stays secure and the door works as intended.
Before applying joint compound, confirm that the profile is straight and firmly fixed. Use compatible materials and keep the recess clear. Compound buildup can narrow the reveal or make it look uneven, especially at corners. Follow the profile maker’s instructions for corner joints and finishing.
After finishing, check:
- Reveal width at the head and along both jambs.
- Whether the frame and wall appear aligned as planned.
- Door swing, latch engagement, and contact with seals or stops.
- Finish cracks, loose edges, compound in the gap, or visible fasteners.
- Required access clearances and any rated-assembly details.
If the door binds or fails to latch, do not hide the problem with extra sanding or by changing a gap without checking the product limits. Find the cause first. It may be frame alignment, floor height, hinge position, or a finish buildup.
Field Examples: Where Flush Details Need Care
These examples are representative planning scenarios, not reports of specific jobs. They show how the same detail changes with wall construction and door use. In each case, I would confirm the profile instructions and project requirements before setting the reveal.
New plasterboard partition: The frame and profile can be planned together before the wall is closed. Set the frame depth from the finished wall thickness, add the required backing, and check the reveal before taping. This is the easiest point to correct a crooked profile.
Existing masonry opening: An uneven opening may need repair or a purpose-made profile suited to the substrate. Measure the wall face and opening at several points. Do not assume a straight frame will make a rough opening look straight; the substrate may need preparation first.
Rated door in a corridor: A flush look does not justify changing the listed frame, seals, hardware, or door clearances. Select only a detail accepted for that assembly, and confirm it against the listing and adopted code. If approval is unclear, pause before cutting or routing.
The lesson is consistent: agree on dimensions and acceptable tolerances before finishing. If the substrate cannot meet them, change the preparation or detail, not the measurement after the wall is complete.
Conclusion: Make the Reveal a Coordinated Detail
Flush architrave detailing works when the frame, profile, wall finish, and door are planned as one assembly. Choose a reveal that suits the selected system, size the frame to the finished wall, and use firm backing and approved fixings. Then verify operation, clearances, and any fire or smoke requirements before handover.
A 10 mm reveal and a 3 mm-in-2 m flatness target can help set a design brief, but neither is a universal code rule. Manufacturer instructions, the approved door assembly, and local adopted requirements govern the final detail.
FAQs About Flush Architrave and Shadow Gaps
These quick answers cover common design and installation questions. Use them as planning guidance, then confirm dimensions and fixing details with the selected system manufacturer and the authority or project team where code requirements apply.
What is flush architrave detailing?
It is a door-opening detail that avoids projecting casing and uses a recessed frame or profile to create a clean wall edge.
What is a shadow gap around a door?
It is the visible recessed line between the wall finish and the door frame or trimless opening profile.
How wide should a door shadow gap be?
There is no universal code width. A 10 mm reveal is a common design target, but follow the chosen profile’s instructions.
Is a 10 mm reveal required by code?
No. It is a typical interior design value, not a general code minimum.
How flat should the wall be near the reveal?
A project may specify no more than 3 mm variation under a 2 m straightedge. Treat that as a finish tolerance, not a code rule.
Can drywall compound hold a shadow-gap profile in place?
Do not assume it can. Use the manufacturer’s specified fixings and provide the required backing.
Should the door leaf be flush with the wall?
It may be flush or deliberately offset. Set the position based on the design, finished wall depth, frame, hardware, and door swing.
Can I use a standard door undercut?
Do not assume one gap suits every door. Check the door manufacturer’s limits and the project’s HVAC transfer-air design.
Can a fire door have a flush architrave detail?
Only if the detail is allowed for that specific listed assembly and meets adopted requirements. Do not modify the door or frame without approval.
When should I check the reveal alignment?
Check it after fitting the frame and profile, before closing or finishing the wall, then inspect it again after finishing.
(This article was written by one of our staff writers, Garrett Vance. Visit our Meet the Team page.)
