Fitting a Door Frame into a Drywall Partition - UA Profile Reinforcement

A standard partition is built on CW studs and UW tracks made of thin galvanised steel. They are fine for dividing a room, but they cannot cope over the long term with concentrated, repeated loads at the hinge points. If the door frame is fixed only into this kind of structure, it gradually works loose. The door starts to drop, it no longer closes properly, and cracks appear in the corners above the opening.

A UA profile looks similar to a CW stud, but it is made from much thicker steel, usually around 2 mm according to the manufacturer. That makes it far stiffer. It can carry the weight of the door and the impact of closing it straight down into the floor and up into the ceiling. The door frame is then screwed into the steel profile, not into the plasterboard.

The installation guides of the large drywall system manufacturers specify UA profiles for standard interior doors, heavier solid leaves, taller doors and flush or concealed frames. For very light doors some systems allow reinforced CW studs instead, but only up to the leaf weight and height the manufacturer states. If you are unsure, the UA profile is the safer choice.

The reinforcement is built while the partition goes up, before any boards are fixed. In practice the sequence usually looks like this:

1. Confirm the type of door frame and the finished floor level, because the size of the opening depends on both.
2. Mark the centre line of the door and the position of the opening on the floor and the ceiling.
3. Cut the bottom UW track at the opening and fix it to the floor.
4. Cut the UA profiles to the full floor-to-ceiling height of the room.
5. Set them on each side of the opening and fix them to the floor and ceiling using the system's connection angles and anchors suitable for the substrate.
6. Check that they are plumb with a spirit level or laser, and that the gap between them is the same at the top and bottom.
7. Form the head and connect it firmly to the side UA profiles.
8. Add short CW studs above the head so the boards have something to be screwed into.
9. Connect the rest of the CW partition so that the UA profiles remain a separate load-bearing frame.

When sizing the opening, allow for the fitting gap the door frame needs. The exact value comes from the frame manufacturer and differs between lining frames, flush frames and concealed frames.

The head is often underestimated, even though it is what holds the shape of the opening. It is usually made from a UW track. The ends are cut and bent into a U shape and screwed to the side UA profiles. For heavier or taller doors, depending on the system, a UA profile is used for the head as well, or a doubled arrangement. The joint must be square and must not sag.

There is one important rule for the boarding: a board joint must never line up with the edge of the door opening. The boards around the door are therefore cut into an L shape, or the joint above the opening is moved some distance to the side. A joint running straight up from the edge of the frame is a very common cause of the cracks that appear above the corner of a door after a while.

With double-layer boarding, the joints in each layer are staggered. The boards are screwed into the UA profile with screws designed for thicker steel, at the spacing given in the system instructions. Narrow strips of plasterboard next to the opening break easily, so it is better to use a full board and cut the opening out of it.

The simplest case is a new partition on a level concrete floor under a solid ceiling, with the door frame type known in advance. The reinforcement is then a routine part of building the partition.

These situations make the job take longer and cost more:

• Reinforcing a partition that is already boarded, where some boards have to come off
• High rooms that need long UA profiles
• Loft rooms where the partition meets a sloping ceiling or timber roof members
• Floating floors or underfloor heating, where the fixings must be planned so they do not damage the pipes
• Timber joist ceilings or suspended ceilings, which are not a suitable base for fixing
• Heavy, tall or flush doors that demand greater accuracy

In a block of flats, let the building management or the owners' association know before you change any partitions. For larger alterations, check with your local building authority what the local building regulations require in your case. Do not assume that a simple notification will always be enough.

The same mistakes come up again and again in practice:

• A CW stud used instead of a UA profile, often justified with "it is only a light door"
• Fixing only into the floor covering, a suspended ceiling or the plasterboard instead of the structural floor and ceiling
• Too few anchors, or anchors not suitable for the substrate
• No fitting gap in the opening, or a height that ignores the finished floor level
• Changing the type of door frame after the steel frame has been built
• A board joint running up from the edge of the opening
• A door frame forced into the opening so the whole frame is under tension

Most of these faults do not show straight after installation. They appear after a few months of use, and putting them right usually means taking part of the partition apart.

Ideally, check the work before the boards go on, while the frame is still visible. When you inspect it, look at the following:

• There really are UA profiles on both sides of the opening, recognisable by the thicker steel
• The profiles are fixed to both floor and ceiling with connection angles
• The side profiles are plumb and the gap between them is the same at the top and bottom
• The head is level and firmly connected to the side profiles
• The height of the opening matches the finished floor and the chosen door frame
• The frame does not move when you push it by hand
• After boarding, no board joint lines up with the edge of the opening
• The fitted door opens easily, does not swing on its own and closes evenly