Gyproc GI Perimeter Section

• Manufacturer: Gyproc (Saint-Gobain)
• Product: GI Perimeter Channel — the edge member of a drywall grid
• Application: Fixed around walls and partitions
• Dimensions: 20 x 28 x 30 x 3660 mm
• Length: 3660 mm (12 feet) — the same as the ceiling section and intermediate channel
• Material: GI — galvanised steel · knurled for screw grip

Gyproc GI Perimeter Channel is the edge member of a drywall grid — fixed around the walls of a room at ceiling height, or around the perimeter of a partition, in a 3660 mm (12 foot) length.

On a false ceiling it does two visible jobs: it supports the ends of the ceiling sections where they meet the wall, and it gives the plasterboard something to screw into around the edge so the board is held rather than floating free against the wall. On a partition it performs the equivalent role, framing the edge where the drywall meets the surrounding structure.

Its most important role is the one that is easy to miss: the perimeter channel sets the level. It goes up first, fixed right round at the finished ceiling height, and everything that follows references it — the intermediate channels hang to suit it, the ceiling sections sit to suit them, and the boards follow the sections.

That makes it the one component where installation accuracy matters more than the specification. Every other part of the grid can be adjusted at the hanger. The perimeter cannot, once fixed. Any error in its level is inherited by the whole ceiling and shows as a line that visibly rises or falls along the wall. Mark the level right round the room first, with a laser or water level, and fix to that line.

It is also the smallest of the three grid members, and that is deliberate rather than a saving. A perimeter channel is fixed continuously to a solid wall, so it never has to span anything. The intermediate channel is a deep section because it spans between hangers; the ceiling section is wide and flat because it presents a face for the board. Each is sized for its job.

Technical Specifications

Applications

1) What does the perimeter channel actually do?

On a ceiling it supports the ends of the ceiling sections at the wall and gives the board edge something to screw into. On a partition it frames the edge where the drywall meets the surrounding structure. Most importantly, on a ceiling it sets the level of the whole installation — it goes up first and everything else references it.

2) Why is getting it level so important?

Because nothing downstream can correct it. Every other part of the grid can be adjusted at the hanger; the perimeter cannot once it is fixed. Its error is inherited by the grid, the boards and the finished surface, and it shows as a ceiling line that visibly rises or falls along the wall. Mark the line right round with a laser or water level before fixing anything.

3) Why is it smaller than the other grid sections?

Because it never has to span. The perimeter channel is fixed continuously to a solid wall, so it does not need bending stiffness. The intermediate channel is deep because it spans between hangers; the ceiling section is wide and flat because it presents a face for the board. Each is sized for its job rather than by importance.

4) Can I use it for partitions as well as ceilings?

Yes — Gyproc specifies it for fixing around walls and partitions. The principle is the same in both: it frames the perimeter and gives the board a fixed edge. Check your partition system's detail for the correct arrangement at floor and head.

5) How many lengths do I need?

Measure the full perimeter at ceiling level — including returns, alcoves and any projecting columns — then divide by 3660 mm and add an allowance for cutting waste at corners. A room with internal features has more perimeter than its floor area suggests.

1. Return within 24 hours of delivery for:
   • Damaged or defective product
   • Wrong or missing item
2. Product cannot be returned once installed or used
3. Refer to Refund Policy for complete details

Please check the channels for bends or transit damage on delivery — a bowed perimeter channel puts a curve into the ceiling edge that cannot be corrected once boarded.