Drywall metal framing

Drywall metal framing is the light galvanised steel substructure of UD, CD, UW and CW profiles that carries plasterboard in partitions and ceilings. The profiles are cold-formed steel. They set where the board fixings land and give the finished wall or ceiling its shape. The Rigips datasheets for its profiles name DX51D+Z steel with a Z100 zinc coating and a thickness of 0.6 mm.

Which profile families make up a drywall frame?

Metal framing for gypsum board comes in a small set of families. The letters tell the jobs apart. C-shaped profiles, CW and CD, are the members that carry the boards. U-shaped profiles, UW and UD, are the tracks and channels at the edges. W marks a wall profile and D marks a ceiling profile (Decke in the German Rigips datasheets). The Rigips environmental declaration lists UD, CD, UW and CW for ceilings, attics and partition walls.

Profile	Position	Web and flange	Steel
UD 28	Perimeter channel for the edge connection of a ceiling	28 mm web, 27 mm flange	0.6 mm
CD 60/27	Ceiling channel that carries the boards	60 mm web, 27 mm flange	0.6 mm
UW 75	Wall track	75 mm web, 40 mm flange	0.6 mm
CW 75	Wall stud	75 mm web, 50 mm flange	0.6 mm
UA 75-2	Reinforcing profile, for example at a door opening	75 mm web, 40 mm flange	2.0 mm

The values come from the Rigips datasheets named in the sources. Rigips also lists R-CW 100 and R-CW 150 studs in its catalogue, and other makers may use other flange sizes. MTC lists CD 60, UD 28, CW 50, CW 75 and CW 100 at 0.6 mm. It lists UA 50, UA 75 and UA 100 at 2.0 mm.

What do the numbers in a profile name mean?

The first number is the nominal web size in millimetres. CW 75 has a 75 mm web, and CD 60/27 has a 60 mm web and a 27 mm flange. The Rigips datasheets give a second code that follows EN 14195, for example C 50/75/50 for CW 75 and U 40/75/40 for UW 75. The last figure of the long name is the steel thickness, as in CW 75 x 50 x 0.6.

A designer picks the web size from the partition depth and from the height of the wall. The Rigips sheets give 4,000 mm for the standard profiles and refer to the supply programme for other lengths.

What does STN EN 14195 cover, and why should a specification cite it?

STN EN 14195 is the Slovak adoption of the European standard for metal framing components in gypsum board systems. The Slovak standards catalogue lists it as an identical adoption of EN 14195:2014. It was released on 1 June 2015, is valid and replaces the 2005 edition. Its Slovak title is Kovové profily pre podkladové konštrukcie sadrokartónových systémov. The title lists definitions, requirements and test methods.

The Rigips datasheets say their profiles follow EN 14195 and the German DIN 18182-1. A specification should name the standard and the profile family. It should also ask for the manufacturer's declaration of the profile, and not describe the profiles by how they look on site.

How far apart are the studs and the channels?

The spacing belongs to the tested system. It is not a general rule. The Rigips fire catalogue of February 2024 says that the spacings and heights printed in it are maximum values. It also says that the insulation thicknesses and the cavity heights are minimum values.

One example from the catalogue is a partition 100 mm thick. It has R-CW 75 studs at 625 mm and one Rigips RB (A) board of 12.5 mm on each side. Its fire resistance is EI 15. The catalogue gives a maximum wall height of 4,700 mm for category A and 3,700 mm for the categories B, C1 to C4 and D. The same catalogue lists other partitions with other boards and spacings. For a ceiling, the hanger spacing and the channel spacing also come from the system datasheet for the board type that you use.

Decision	What it controls	Where the value comes from
Profile family and steel thickness	Stiffness and the load of the frame	The manufacturer datasheet, for example 0.6 mm and 2.0 mm
Stud and channel spacing	Board stiffness and fixing density	The tested system, as a maximum value
Hanger spacing in a ceiling	The load path of the ceiling grid	The system datasheet of the maker
Corrosion class	Suitability for humid rooms	Rigips lists a UW 75 for classes C3 to C4 and a CW 75 for class C5, and MTC lists strips for C3 and C5

Which board types go on the frame?

The board follows the room and the fire requirement. The Rigips fire catalogue lists the boards for each fire-resistant assembly. One example is RF (DF) boards of 12.5 mm for a ceiling with a fire requirement. The board type must match the tested assembly. The article on gypsum plasterboard explains the board types.

How does drywall framing differ from structural steel framing?

Drywall metal framing is a substructure for boards. The Rigips datasheets describe the profiles as the basis for substructures in gypsum board systems. A lightweight steel framing system is a different thing. It is a structural building system in which the steel members carry the loads of the building. A drywall frame is fixed to the structure and does not replace it. A partition built with it is a non-load-bearing partition, and a ceiling built with it is a suspended ceiling.

How does the frame meet an access panel or a door?

The frame changes where an opening goes in. For a ceiling opening, the Rigips catalogue says the profiles are interrupted at the opening and trimmers are inserted into the structure. For a hatch in a partition or a ceiling, it asks for trimmers. The profile faces then stay at most 100 mm from the hatch frame. For a reinforced door opening, Rigips offers the UA 75-2 profile. The article on the ceiling access panel shows where hatches belong.

What should the site check cover?

• The profiles on site match the specified family, web size and steel thickness.
• The studs and channels are no farther apart than the tested system allows.
• Trimmers are in place at every opening before the first board is fixed.
• The corrosion class suits the room, for example a humid room.

Record any deviation before the first board goes on. After that the frame cannot be inspected without damage to the finish.