How do I put a doorway in a stud wall?

The framing of a door opening in a partition is simple and specific: two full-height studs each side of the opening for stiffness, a horizontal head over it, and short studs above to keep the board supported. What causes trouble is the setting out — an opening framed to the door size rather than to the door plus lining plus tolerance either does not fit the door or leaves a gap that has to be packed.

Safety

What you'll need

• Timber to match the existing studs
• Door lining set
• Long level and a framing square
• Saw, drill driver and screws
• Cable and pipe detector
• Plasterboard and jointing materials
• Adjustable props, if working in an existing wall of any doubt (optional)

Step by step

1. Establish whether the wall is load-bearing.In an existing wall, this comes first and is not negotiable. Look at what is above: joists bearing on it, a wall above it, a roof member. A stud wall can carry load. If there is any uncertainty, that is a structural engineer's twenty minutes, not a guess.
2. Detect and isolate before you cut anything.Cables run vertically and horizontally in partitions, and a wall with a socket on it certainly has a cable in it. Scan the whole area, isolate the relevant circuits, and open the wall carefully rather than sawing blind.
3. Buy the door and the lining before you frame anything.Standard door sizes vary, and a lining set has a defined thickness. Frame to the actual components you have bought, not to a nominal size.
4. Calculate the structural opening.Door width, plus the lining thickness on each side, plus a fitting tolerance of a few millimetres each side for packing and adjustment. Height is the door height plus the lining head, plus the tolerance, plus the floor covering thickness under the door.
5. Set the opening out on the floor and mark it up.Position it with the door swing, the light switch, the adjoining wall and the furniture in mind. A door hard against a corner cannot open fully and there is nowhere for the architrave to land.
6. Fit the full-height studs either side.Doubled studs each side of the opening, running from sole plate to head plate, fixed to both plates. These are what stop the opening racking as the door is used.
7. Fit the head across the opening.A horizontal timber across the top of the opening, fixed into the studs either side. In a non-load-bearing partition this is carrying only the board and the door frame, so a single member matching the stud depth is adequate.
8. Fit cripple studs above the head.Short vertical studs from the head to the head plate, at the same centres as the rest of the wall, so the board above the door is supported and its joints land on timber.
9. Cut the sole plate out through the opening.In a new wall, the sole plate can run through while you build and be cut out afterwards, which keeps everything aligned. Cut it flush with the inside face of each opening stud.
10. Check the opening is square and plumb before boarding.Measure both diagonals — they should be equal — and check both sides for plumb. Correct now. A racked opening means a door that binds at one corner and no amount of hinge adjustment will fix it.
11. Board, then fit the lining.Board up to the opening, then fit the lining set, packed and wedged until it is plumb, square and the right width at top, middle and bottom. The lining, not the framing, is what the door is actually hung from.
12. Fit the architrave last, after the wall is finished.It covers the junction between lining and wall and hides the tolerance gap. Set it out with a consistent reveal along the edge of the lining.

Tips

• Check the diagonals of the lining after every wedge you tap in. Linings move as they are fixed and a lining that was square when you started often is not by the end.
• Leave the sole plate running across the opening while you frame and board — it keeps the studs at the right spacing and stops the opening spreading. Cut it out at the end.
• If the wall is going in a room that already has a light switch on it, plan the new switch position before framing so the cable can be run inside the wall rather than surface-clipped afterwards.
• For an opening without a door — an arch or a cased opening — the framing is identical; only the lining and the finish change.

Common mistakes

• Framing to the door size — The lining takes up space on both sides and at the top, and there has to be tolerance for packing. An opening framed to the door width cannot take a lining, let alone a door.
• Cutting an opening in an existing wall without checking what it carries — Timber partitions are routinely load-bearing. Removing studs from one that is carrying load transfers that load onto the boarding, which cannot take it.
• Skipping the cripple studs above the head — The board over the door has nothing to fix to in the middle, so it moves and the joints above the door crack — one of the most common crack locations in any house.
• Not checking the diagonals — A racked opening produces a door with an uneven gap that catches at one corner, and it cannot be corrected at the hinges.

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