How to Fit a uPVC Door and Frame

A uPVC door and frame goes in the way a window does, with three differences that decide whether it works. The frame is fixed deeper into the wall. The threshold has rules of its own. And the door has to lock, which means a frame a few millimetres out of square shows itself every time you turn the key. Most of the guides that rank for this are suppliers' fitting sheets: they cover the sequence and say nothing about the building notice, the council fee or the threshold. This guide takes the numbers from FENSA's compliance guide and the Glass and Glazing Federation's good practice guide, which both cover doors, and the fitting sheets from Wickes, Crystal and Just Doors where the makers are more specific. For a window, the sequence is in how to fit a double glazed window.

Before you order: measure the opening and check the lintel

Measure the brick opening, never the old frame, in three places across and three down, and use the smallest of each. The GGF guide applies the same deductions to external doorsets as to windows (the method is set out step by step in how to measure windows), and they are totals, not per side: for white uPVC, 10 mmoff the width and off the height of anything up to 3 m, which covers a standard single door both ways; for coloured or foiled uPVC, 15 mm. Allow for the mortar or sealant bed under the cill in the height. That leaves about 5 mm a side, which is the gap Crystal and Express Trade ask for; Dunster House says a minimum of 4 mm all round. One supplier, Just Doors, says in one line to order 10 mm smaller "on all sides" and in the next that this gives a 5 mm gap each side; the second reading is the one that agrees with everyone else.

Check the opening is square by measuring the diagonals. The two sources disagree on how square is square enough: the GGF guide allows 10 mm across the diagonals of the opening, while Just Doors treats more than 2 mm as out of square. The frame itself should be within 2 mm once it is in. Where the new frame will not fill the opening, add-on profiles belong on the hinge side, to give the hinges clearance (FENSA). Look above the opening too: Wickes and Just Doors both say a suitable, load-bearing lintel must already be in place, and FENSA's structural rules apply to doors as well as windows. Widening the opening, with the new lintel that goes with it, is outside FENSA and needs a building control application whoever fits the door.

When the door arrives, do not take the old one out until you have checked the new one. Inspect it for damage, then lay the frame flat and open and close the leaf; Just Doors and Dunster House both say not to start if anything is wrong. Wickes goes further: claims for damaged glass, a marked finish or missing parts must be made before installation, not after.

Taking the old door out

Lift the leaf off its hinges first. For a timber frame, cut the seal between frame and wall with a sharp blade, take out any fixings you can find, then saw through each jamb, one installer says about 150 mm above and below the middle, and lever the pieces inward with a flat bar. A uPVC frame is easier: through-frame fixings usually unscrew, and fixing brackets can be cut with an angle grinder (GGF). Chip old mortar off the reveal with a bolster until it is clean and flat. The general cautions for taking a frame out, from asbestos to disposal, are covered for windows in how to remove a double glazed window.

With the frame out, look at what it was sitting on. The GGF guide says to confirm whether the opening has a conventional sill or a low, accessible threshold, and to inspect the damp-proof course and the vertical DPC for damage and repair them before the new door goes in. FENSA adds the cavity closer or damp-proof membrane in a cavity wall, and the GGF guide says any open cavity between the inner and outer skins should be closed with an insulating material.

The sequence

1. The cill and threshold

Wickes starts with a damp-proof membrane along the bottom of the opening. The cill fixes to the bottom of the frame: silicone along the inner raised edges of the frame's bottom rail without blocking its drainage holes, then screws near each end. Just Doors specifies 50 mm self-tapping screws, the first 150 mm from each end, and no more than 500 mm apart. Seal the end caps on, because, in Just Doors' words, water that tracks behind the cill into the cavity "can cause significant structural damp that is costly to repair". FENSA wants the frame coupled to the cill with a continuous weather seal, and accepts bedding the cill on foam with a perimeter seal after, or on silicone where access is tight. Where the old door had a low threshold, the GGF guide says to fit the new one the same way, with a DPC between the threshold and the stone or timber sill and sealant between the two. Level the cill with packers; everything above is set from it.

2. Level, plumb and square

This is the step Just Doors calls "the most critical step of the entire installation". Stand the frame on the cill, then work in order: cill level, hinge jamb plumb, lock jamb plumb, head level, and the diagonals equal to within 2 mm. Wickes adds a long straight edge across the face to check the frame has not bowed, and says plainly that the door and lock will not work properly if the frame is fitted incorrectly. Pack at all four corners and the middle of each jamb, and at every point a fixing will go. On a door, the GGF guide asks for more than that: because of the forces of the door opening and shutting, add packers beside the hinges and beside the locking points. Wickes says two people may be needed to lift the frame in; Just Doors says never to attempt it alone. Wickes' one-person route is to lift the leaf off its hinges first, if there is room above the frame to lift it back on.

3. Fix the frame

Fix all four sides wherever practicable, through the frame into the wall or with lugs and straps, and at least 50 mm into masonry. That is the door figure in both FENSA's compliance guide and the GGF guide, against 40 mm for windows; both say 25 mm into a timber-framed wall, where Just Doors asks for 60 mm. The fitting sheets specify frame fixers of 7.5 mm by 100 to 120 mm. Fix the hinge side first and re-check plumb after each fixing. Always fix through a packer, never into a void, and do not over-tighten: Just Doors warns that too much torque bows the frame so the door will not close or lock, and Wickes puts silicone under each screw head and checks the frame width as it goes. On the lock side, put a fixing as close as you can to the keeps. Expanding foam is not a fixing; the GGF guide says it may supplement mechanical fixings but must never be the only thing holding the frame.

The spacing is where the sources split. FENSA and the GGF guide set the rule at a minimum of two fixings a jamb with no more than 600 mm between them, and the GGF puts corner fixings 150 to 250 mm from the corner. Several door makers ask for half that spacing, and the one explanation found is security testing: Crystal's guide, in its patio door section, says that for PAS 24 the fixing centres drop to 100 mm from each end and no more than 300 mm apart. So 600 mm is the ceiling, and the maker's sheet for your door is the rule.

Source: FENSA Guide to Compliance v2023.07; GGF A Guide to Good Practice 20.3 (April 2016); manufacturers' and suppliers' fitting instructions. Research in lib/research/fit-upvc-door-2026.md.

4. Glaze and hang the leaf

On a glazed door, the packers under the glass are what hold the leaf square. Toe and heel them: on the hinge side the packers go at the bottom corner, on the lock side at the top corner, about 150 mm in from the edge, with a dab of silicone to stop them slipping (Crystal). Without it, Crystal says, the door will drop on the handle side, and Just Doors charges for a service call if it finds a door that was not toe and heeled. Refit the beads in the positions they came out of; the sheets disagree on whether short or long beads go first. Rehang the leaf by lifting it over the hinges with the pins lined up. Wickes says its doors are factory set to hang correctly, needs 8 mm of sash overlap on the lock side for weatherproofing, and sets the keeps by carrying a pencil line from the lock groove across to the jamb. Any fine-tuning after that is a hinge job, covered in how to adjust a uPVC door.

5. Seal it

Fill the perimeter gap with low-expansion foam or expanding foam tape. Just Doors is emphatic that high-expansion foam will bow a uPVC frame until the door cannot be locked. Outside, a continuous bead of low-modulus, neutral-cure silicone; the GGF guide specifies a sealant rated 20LM or 25LM, both sides of the frame, with a foam backer rod in any gap over 6 mm. Seal under the external cill too (Crystal), but not over the drainage holes in the face of the threshold, which FENSA says must stay clear and working. Never fill the gap with sand and cement. Take the protective film off the inside before fitting and the outside once the sealing is done, and do not leave the panels in direct sun, which bonds the film to the skin.

6. Test it

With the door shut, check every hook and bolt on the multipoint lock engages. If the key is stiff, Wickes says not to force it, and not to work the handle and key together, which can knock the lock gearing out of sequence. If you are upgrading the cylinder while the door is new, how to change a uPVC door lock covers sizing and grades. Clear any foam or silicone from the drainage slots. The GGF guide's own final checklist asks four questions worth copying: is the frame plumb and square, are the drainage channels clear, are the cill end caps fitted, and is safety glass used where it needs to be?

A door frame a few millimetres out of square hangs, opens and closes perfectly well, and then the hooks miss the keeps. Check the diagonals before the last fixing goes in, because afterwards the only fix is taking it out again.

Double Glazing Cost Calculator Team

The rules you take on

Whether you have to tell anyone depends on the glass. Schedule 4 of the Building Regulations 2010 lists replacing an external door, where the door and its frame have not more than 50% of the internal face glazed, among the jobs that need no building notice. The door must still meet the regulations. A door more than half glazed is different: a registered installer self-certifies it, and if you fit it yourself you give a building notice to your council before you start, are inspected, and get a completion certificate. Glazed side panels count as separate windows, so a door with two side panels is, in FENSA's example, one door and two windows, and the windows are notifiable. The Planning Portal calls any external door a controlled fitting, which is right about the standards it has to meet; the exemption from notifying is in Schedule 4.

Councils set their own fees. For 2026/27, Oxford charges £400including VAT for replacement windows and doors (up to seven windows and two doors at once) and £500 to regularise work after the event; Winchester £315 for one to four installations; Buckinghamshire, on its proposed schedule, £242.55 for a building notice covering up to 20. Check your own council's schedule, and notify before you start: one supplier points out that retrospective applications cost more and that building control can only inspect what is still visible. Our FENSA guide covers what the certificate is worth when you sell.

Source: legislation.gov.uk (Schedule 4, revised text 2026-09-19); Approved Document L Vol 1, 2021 edition incorporating 2023 amendments; FENSA Guide to Compliance v2023.07; Planning Portal. Wales publishes its own Approved Document L; Scotland has its own building standards.

Two of those deserve a second look. The threshold rule applies to the main entrance: FENSA says the height of the new threshold should be no higher than the previous one, the Planning Portal applies it to homes built since 1999 and the GGF guide to those since 2004, and the GGF adds that Part M never requires a replacement to give better access than the door it replaces. Back and side doors are not covered. And Part L applies to the whole door and frame; hanging a new leaf in the old frame is not a controlled fitting at all. On ventilation, one supplier says a replacement door generally needs background ventilation even where the old one had none; FENSA's guide is silent on doors, so ask building control, and see our trickle vents guide for how the window rule works. Security is a matter of what you buy rather than what the regulations require; the doorset and cylinder questions are in uPVC vs composite doors.

When to leave it to a fitter

Some doors are not a uPVC DIY job at all. A flat's entrance door onto a shared landing needs fire resistance; the Leasehold Advisory Service says current standards call for FD30, and, one supplier notes, the lease itself often restricts changes to the front door, including its colour. So does the door between an integral garage and the house. FENSA adds that a rated fire doorset does not make an installation compliant on its own; the fitting is inspected too. Beyond those: an opening that needs widening or a new lintel, a main entrance where the new door would raise the threshold, and a heavily glazed door where you would rather not deal with building control. In Scotland, one installer says replacing a door needs no building warrant unless the opening changes; that rests on a single installer's blog, so check with the council.

What it costs, and what you give up

Source: Checkatrade (June 2026), MyJobQuote (July 2026), retailers' prices on 19 September 2026, council fee schedules 2026/27. The £250 to £500 'uPVC door' figure on several sites is a door-only price, not a fitted one.

Fitted, a uPVC door and frame is £460 to £1,200 in 2026, typically around £700: both Checkatrade and MyJobQuote start at £400, and Checkatrade's average is £700. The door alone, from a retailer, starts at £499 (Just Doors, a half-glazed back door) to £580 (Wickes, a pre-hung front door). The cheapest supply-only doors cost more than the bottom of the cost guides' fitted ranges, and none of them explains why, so do not work out a saving from the two. Labour on its own is £150 to £350 (MyJobQuote) or £140 to £220 for the frame (Checkatrade); Checkatrade's front door page quotes £500 to £1,000 for labour, which neither its own frame guide nor MyJobQuote supports. A professional takes two to six hours (Checkatrade), or two to five (MyJobQuote). You will see £250 to £500 quoted for a uPVC door on several sites; it is the same door-only figure copied between them, labelled fitted on some, and it is not a fitted price.

The guarantee is the other cost. Wickes keeps its 10-year guarantee on a door you fit yourself, but it does not cover "any fault arising from incorrect installation", not following the instructions may void all or part of it, and replacement parts are supplied with no allowance for fitting them. Just Doors guarantees profiles and door slabs for 10 years, sealed units for five and hardware and locks for one, and will not pay for labour to fit a replacement part. What you lose outright is the insurance-backed guarantee: FENSA says it is bought by the installer on your behalf, and HomePro says it has been mandatory for registered installers since June 2014, with at least six years of cover. A DIY fit has none. The wider trade-off is in supply-only vs fully fitted, and the door cost calculator prices the door fitted.

If you would rather a registered fitter did it

The saving on a self-fit is the £150 to £350 of labour, set against the building notice on a glazed door, the guarantee you give up and the time it takes to get the frame square. For a fitted price on your own door, with removal and certification included, tell us what you need and Leads 2 Trade will arrange quotes from installers covering your postcode.

Price-checkedLast reviewed 19 September 2026

Reviewed byDouble Glazing Cost Calculator TeamCross-checked against Checkatrade, the FMB & GreenMatch