Why does my stud wall flex when I push it?

Timber stud partitions are light by design and a certain amount of give between the studs is normal, especially with 9.5mm board. What is not normal is the whole panel moving, a wall that visibly rocks, or one that has started moving when it did not before. Distinguishing the two takes a minute and decides whether you are looking at a comfort issue or a construction fault.

What you'll need

• Stud detector
• A long spirit level
• Screws and a driver
• Cable and pipe detector

Step by step

1. Push at several points and map the movement.Mid-bay at waist height, directly over a stud, near the floor, near the ceiling, and at each end. Where it moves — and where it does not — is the diagnosis.
2. Movement only in the middle of each bay: thin board or wide studs.Nine and a half millimetre board on 600mm centres will always have some give. It is cosmetic rather than structural, and it is fixed by overboarding rather than by anything drastic.
3. Movement including over the studs: the framing is moving.Check whether the wall is fixed at the head and the ends. A partition should be screwed to the ceiling joists above, to the floor below, and to the adjoining walls at each end.
4. Check the head fixing specifically.A head plate has to be fixed into joists above, and where the partition runs parallel to the joists rather than across them, there needs to be noggins between the joists to fix to. A head plate screwed only into a ceiling's plasterboard is a common and genuinely poor detail.
5. Check the ends.The end studs should be fixed into the walls at each end — into masonry with plugs, or into the studs of the adjoining partition. A partition free at one end will always sway.
6. Check for noggins.Horizontal noggins between the studs stiffen the frame considerably and stop the studs twisting. A wall with none feels noticeably springier than one with a row at mid-height.
7. Refix what you can reach.Screws through the board into the head plate and joists above, into the floor plate, and into the end walls. Detect for services first, and go into timber rather than into board.
8. Add noggins or a second layer where you cannot.Where the frame is fixed but the wall is simply lively, an additional layer of 12.5mm board substantially stiffens it and doubles the mass, which helps with sound as well.
9. Treat a wall that has started moving as a different problem.A partition that was stable and now is not has had something change — a fixing has failed, a floor has moved, or something above has. Establish why rather than just screwing it back.

Tips

• A wall that flexes will crack at the joints and will not hold fixings well, so it is worth stiffening before you hang anything heavy or tile it.
• If you are about to tile a stud wall, movement matters much more — tiles are rigid and a flexing background cracks grout and pops tiles. Overboard, add noggins, or use tile backer board.
• Metal stud partitions are inherently more flexible than timber, and a single skin of board on metal studs at 600mm centres will always feel lively.

If it doesn't work

Questions people ask