Technical resource
Trimless ceiling coordination
A trimless detail is decided before the ceiling is built, not when the luminaires arrive. This guide sets out the information the ceiling contractor needs from the lighting schedule, and the sequence that keeps the plaster line clean.
Technical review: LUMIBRIGHT technical team · Lighting application engineering · Revision 2026-09-26
What specifiers ask
What ceiling depth and cut-out are needed?
Take both figures from the model drawing, never from the family range: the cut-out sets the opening and the recess depth sets the void, including clearance above the fitting for the driver and cabling. Where the void is shallower than the model requires, change the model rather than the detail.
When should plaster-in frames be installed?
Plaster-in frames are fitted with the ceiling board, before skimming, so the plaster is finished up to the frame edge. Ordering them with the luminaires usually means they arrive after the ceiling is closed.
Which models are truly trimless?
Only the models whose drawings show a plaster-in frame or a flangeless housing. A shallow bezel is not a trimless detail, and we do not describe a family as trimless where the drawings show a visible trim on some models.
How is the fitting serviced once the ceiling is skimmed?
Confirm whether the driver is integral or remote, and record the access position in the schedule. A remote driver needs an accessible location agreed with the M&E contractor.
Related pages
Request a sample for the ceiling mock-up
Send your reflected ceiling plan, room dimensions or lighting schedule. Include the project location, stage and required date so the team can confirm suitable models and the documentation available.
