The advice on this is split down the middle. Half the guides say to turn the hinge screw one or two full turns and see; the other half say a quarter turn and no more. Half say start at the top hinge, half the bottom. One installer says the top cap on a flag hinge is height, the hinge maker's own instructions say it is compression. They are all describing real hinges, and the disagreement is the lesson: the adjusters differ by maker, so the method is to identify what you have, turn a little, and watch what moves. This guide gives you the order of work that holds whatever hinge is on the door.
Before the allen key: two checks
First, the guarantee. A door under ten years old is very likely still covered on the frame, though some suppliers cover hardware and locks for much less (Just Doors gives them one year), and an installer visit costs you nothing and rules out a fitting fault. Second, the door-open test, which separates the two problems people confuse most. Open the door, lift the handle and turn the key. If it locks smoothly in mid-air, the handles, the multipoint strip and the cylinder are all fine, and your problem is alignment: the hooks and rollers are not meeting the keeps when the door is shut. If it grinds or will not lock even with nothing to catch on, lubricate the mechanism first, which the locksmiths' trade body says is often the cause when the handle will not lift; if that does not free it, the gearbox inside the lock has failed, and no amount of hinge work will help. The same body puts gearbox failure as the commonest reason a uPVC door will not lock while open. Telling the gearbox from the cylinder, and replacing either, is covered in how to change a uPVC door lock.
Which hinges you have, and what each one adjusts
- Flag hinge. A rectangular body on the frame with a hinged flag on the door, usually with plastic cover caps. Fitted to most uPVC and composite doors from the last twenty years and the only type that adjusts all three ways: height (up and down, typically about 4 mm of travel), lateral (sideways, about 5 mm each way) and compression (in toward the seal, about 2 mm). One screw per direction, usually a 5 mm allen key, sometimes a 4 mm.
- Butt hinge. Two flat leaves on a pin, the oldest type and still common on older doors. Some adjust sideways by up to 2 mm through two Phillips screws on the side, and up and down through an allen screw under the top cap; some have a grub screw in the face that must be slackened before the pin will move; some do not adjust at all.
- T-hinge. Similar to a flag hinge but shaped like a T, fitted to heavier doors. Usually height and lateral only, and often by slackening the fixing screw and repositioning the hinge rather than winding an adjuster. Compression is rarely available.
Which screw does what on a flag hinge varies by maker. On one common Yale pattern the top cap hides the compression adjuster and the bottom cap the height; on others it is the reverse. Mark the starting position with a pencil, turn, close the door, and see what moved. The same rule that applies to window hinges applies here: identify the hardware before you follow anyone's instructions, including these.
The fault tells you which adjustment to make
| What the door does | What has happened | Adjust |
|---|---|---|
| Drags on the threshold or floor | Dropped on the hinges | Height, all hinges together |
| Gap along the top, tight at the bottom | Dropped at the handle corner | Height, then square it (see below) |
| Handle lifts, key will not turn | Hooks missing the keeps | The keeps first, then lateral |
| Draught along the hinge side | Sitting too far out from the frame | Compression, hinge side |
| Draught along the handle side | Not enough compression on the lock side | Compression, and check the keeps |
| Touches top and bottom, gaps in the middle | The door has bowed | Nothing. Adjustment will not fix it |
Where two rows match, deal with height first. A height error creates the gaps that look like a compression problem.
Height: the door has dropped
Pop the cover cap on the height adjuster of each hinge and turn clockwise a quarter to half a turn, close the door, and check the drag. Repeat until it clears. Do it on every hinge in turn, not one hinge several turns: all three must carry the door together, and lifting one alone puts the whole weight on it and it will fail. The travel is only a few millimetres, and if you run out of thread with the door still dragging, stop. Either the frame has moved or the door has dropped further than the hinges can correct, and both are fitting questions rather than hinge questions; how a door frame should be packed and fixed is in how to fit a uPVC door.
If the drop is at the handle corner rather than all along the bottom, the fix is squaring, not lifting. Using the lateral adjusters, move the top hinge a fraction toward the wall and the bottom hinge a fraction toward the opening. That twists the door back to square and lifts the leading corner. Two millimetres at each end is plenty, and you must check that no gap has opened on the hinge side, because that is where the draughts and leaks come from next.
Lateral: the door is off to one side
The side adjuster moves the door toward or away from the hinge jamb. Use it to even up the gap down the lock side, which should be the same at the top, middle and bottom with the door shut. Adjust the hinges evenly; uneven lateral adjustment twists the leaf and creates draughts you will spend the rest of the afternoon chasing. Lateral is also the second thing to try when the lock will not throw, after the keeps.
Compression: the door seals too tight or too loose
The compression adjuster moves the door in toward the gasket or out from it, by about 2 mm in total. Too little and you get a draught down one side; too much and the handle needs both hands, the gasket flattens, and the seal stops working within a couple of seasons. The hinge makers are specific about this one: turn each compression adjuster no more than 45 degrees at a time, in sequence, and never force it. Test with a sheet of paper: shut the door on it and pull. You want firm resistance without tearing, and the same resistance at the top, middle and bottom. Paper that tears at one corner and slides free at another means the door is out of square, and you are back to height, not compression.
Seasonal binding is a compression problem too. uPVC grows in summer heat and shrinks in winter cold, and a millimetre or two is enough to stop a multipoint lock engaging. A door set tight in January binds in July. Back it off a fraction rather than forcing the handle, because a lock forced against misaligned keeps is how gearboxes die.
The keeps: where most DIY attempts go wrong
The keeps are the metal plates on the frame that the hooks and rollers on the lock strip engage with. When the handle lifts fine but the key will not turn, or the door needs a shoulder to lock, the hooks are missing or fouling the keeps, and the instinct is to adjust every hinge in sight. Look at the keeps first, with the door open. Most sit on slotted screw holes, which means they move. Bright scrape lines on the metal show exactly where the hook is hitting and which way it needs to go. Slacken the screws, shift the keep two or three millimetres in that direction, and retighten. One turn is enough to loosen and tighten; the screws are small and often have a square nut behind, so do not take them right out.
The rollers on the lock strip are adjustable too, on most doors: a small cam with a line on it, turned with a 4 mm allen key. Turning the line inward increases compression on the lock side, which is the answer to a draught down the handle edge when the hinges are already right. Note the difference from a window that will not lock, which has its own set of causes in what to do when a window will not close.
The door-open test takes ten seconds and it decides the whole job. If it locks in the air, you have an alignment problem and the keeps are the first thing to touch. Most of the hinge fiddling we see was done on doors whose hinges were never the fault.
Double Glazing Cost Calculator Team
Glazed doors that have dropped: toe and heel
On a door with a large glass panel, the glass is most of the weight, and it is the glass that holds the door square, not the frame. It sits on plastic packers at the corners, placed so the weight runs from the top handle-side corner down into the bottom hinge-side corner. When those packers slip or were never fitted, the handle corner sags, and no hinge setting will hold it for long. The repair is called toe and heel: take the glazing beads off, lift the glass with a plastic glazing paddle (never metal against glass), and re-pack the top handle-side and bottom hinge-side corners until the door squares up. A pencil line on the frame level with the top of the door before you start shows you exactly how far it has dropped and when it is back. Bead removal is the same job as on a window, described in our blown double glazing guide.
What it costs if you would rather not
An alignment visit from a locksmith or glazier is £60 to £120and takes 15 minutes to an hour; the trade guides, the locksmith directories and the Master Locksmiths Association all land in that band. Hinges themselves are cheap parts, £12 to £16 each, with labour at £30 to £50 an hour on top, so a full set of three replaced is in the low hundreds. The expensive fault is the one adjustment does not reach, the gearbox, and repair and replacement are different prices. The Master Locksmiths Association's price list has a gearbox repair from £85; its own gearbox pages put a fitted replacement at £145 to £280 and £175 to £335. A complete new multipoint strip is £120 to £300 on Checkatrade's January 2025 figures, and can pass that on dearer makes, where the MLA puts the parts alone at up to £263 or more. The MLA says most emergency locksmiths do not charge a call-out fee, though MyBuilder lists £50 to £150 for one out of hours and Keytek £100 to £130, and out-of-hours rates rise sharply, so a door that still locks by hand can wait for a weekday.
Adjustment stops being worth it when the door itself has gone: a bowed leaf, a frame that has moved, or a twenty-year-old door whose hinges, gearbox and gaskets are all tired at once. At that point the comparison is with a new door, which the door cost calculator prices for each type. If the replacement is a choice of material, uPVC vs composite doors sets out what the extra money for composite does and does not buy.
| New door, fitted | Low | Typical | High |
|---|---|---|---|
| uPVC front door | £460 | £700 | £1,200 |
| Composite front door | £1,150 | £1,500 | £2,500 |
| French doors (uPVC) | £1,100 | £1,650 | £2,200 |
Source: front doors from Checkatrade (June 2026), MyJobQuote (July 2026) and Costwise (June 2026); French doors from the DGCC 2026 door dataset. Composite doors use the same flag hinges and adjust the same way; they are heavier, so they drift more.
If it is the door, not the adjustment
A dropped door on sound hinges is a ten-minute fix and the figures above are the whole story. Where the leaf has bowed, the frame has shifted, or the door is old enough that the gearbox and gaskets are going too, the repairs start to add up against a new door. If you want that priced on your own opening, tell us what you have and Leads 2 Trade will arrange quotes from installers covering your postcode.
Frequently asked questions
On a flag hinge, the commonest type on modern uPVC doors, take the cover cap off the height adjuster, put a 5 mm allen key in and turn clockwise a quarter to half a turn, then close the door and check. Lift on all three hinges together, not just one, or the one you lifted carries the whole door and fails. If the door has dropped at the handle corner rather than all over, square it instead: top hinge a touch toward the wall, bottom hinge a touch toward the opening.
A 5 mm allen key covers most flag hinges, including the ERA and Yale types fitted to the majority of UK doors, and a 4 mm covers most of the rest, including the roller cams on the lock strip. Have both. Some older butt hinges use Phillips screws for the sideways adjustment and an allen key under a cap on top for height.
Open the door and try it. If the handle lifts and the key turns with the door open, the lock is fine and the door is out of alignment: the hooks are missing the keeps on the frame. The fix is usually the keeps, not the hinges. Most have slotted screw holes; slacken them, move the keep two or three millimetres in the direction the bright scrape marks tell you, and retighten. If it will not lock even with the door open, lubricate the mechanism and try again; if that does not free it, the gearbox has failed and adjustment will not help.
uPVC expands in heat and contracts in cold, and a millimetre or two is enough to stop a multipoint lock engaging. A door adjusted tight in January binds in July. Back the compression off a fraction in summer rather than forcing the handle, because forcing a lock that is out of alignment is how gearboxes get broken.
An alignment visit is £60 to £120 from a locksmith or glazier and takes 15 minutes to an hour. If the hinges themselves are worn, the parts are £12 to £16 each plus labour at £30 to £50 an hour. A failed multipoint gearbox is two prices: repair from £85 on the Master Locksmiths Association's price list, a fitted replacement £145 to £280 or £175 to £335 on its gearbox pages. A full new lock strip is £120 to £300 on Checkatrade's figures, more for dearer makes.
Three cases. A door that touches the frame at the top and bottom but gaps in the middle has bowed, and no hinge setting will straighten it. A frame whose diagonals differ by more than a few millimetres has moved in the opening, and the door is only the symptom. And a glazed door that has dropped at the handle corner with the hinges already at the end of their travel needs the glass re-packed, called toe and heel, rather than more hinge adjustment.