Composite back doors: solid, half-glazed or with a large glass panel
Rockdoor and GRP composite back doors for a kitchen, utility room or any other rear entrance, each made to measure with a new frame and fitted by Jim and Josh. No salespeople, no subcontractors.
From £1,500 GRP·From £1,900 RockdoorFitted, including VAT
Prices last updated October 2026. They’re estimates that vary with the specification; your quote gives the exact price.
What a fitted composite back door costs
A composite back door costs from £1,500 fitted for GRP and from £1,900 for a Rockdoor. That includes VAT, the new frame, fitting, and taking your old door and frame away.
Composite back door
Fitted, inc VAT
GRP back door, clear glass
From £1,500
Rockdoor back door, white, with clear or privacy glass
What usually moves the price at the back is a colour other than white (£70), a glass design (£80–£260), a low threshold (£20) and a cat flap (about £70). Each one is under Options below. For every door we fit, see our composite door prices guide.
Two ranges
Two ranges of composite rear door, each surveyed and fitted by us at one all-inclusive price.
Rockdoor or GRP: which composite back door should you choose?
Both of our back door ranges have a foam core, a tough outer skin, multi-point locking and a high-security cylinder. For a back door, the choice usually comes down to your budget and how exposed the door is.
From £1,900 fitted
Rockdoor composite back doors
The most secure back door we fit. A high-density polyurethane foam core and an aluminium-reinforced frame, with S-Glaze technology that seals the glass into the door so it can’t be removed from outside. Well worth having on a door that sits out of sight.
Winkhaus multi-point locking and a 3-star anti-snap cylinder
Glass-reinforced plastic skins over an insulating foam core, with a woodgrain finish that won’t fade, peel or crack. A big step up from a tired uPVC back door, at a more accessible price.
5-point locking and a 3-star anti-snap cylinder
Steel-reinforced uPVC frame
Solid panels, half-glazed styles and obscured glass
You choose the outside colour; the inside is white
Both ranges come with a 10-year manufacturer’s guarantee. If your back door is hidden away down a side passage or behind a fence, Rockdoor’s extra security is worth a look. If it is in plain view, GRP gives good protection for less. Send us a photo of your back door and we’ll give you a price for both.
Styles
The styles our customers pick most for the back of the house. Any Rockdoor style can go at the back.
The back door styles our customers choose most
The Windsor is the style people choose most for the back: its large glass panel brings the most daylight into a kitchen. Next come the Vogue and the cottage styles. We also fit plenty of Jacobean, Aspen, Manhattan and Classic doors at the back. The photos below are doors of each style we’ve fitted.
We fit composite back doors only. This is how the two compare, so you can decide.
Composite or uPVC back door?
Replacing a tired uPVC back door, one that has dropped, gone draughty or discoloured? Here’s how a composite back door compares.
Composite (what we fit)
uPVC
Inside the door
A foam core under a hard-wearing skin, so the door is thick and heavy
A plastic sash with a flat infill panel, much lighter
After a few years
Holds its shape and colour, with no painting
Can drop on its hinges and discolour
Warmth
A foam core; Rockdoor rate their styles A or B for energy
Depends on the panel and the glass
Locking
Multi-point locking and an anti-snap cylinder on every door we fit
Multi-point locking too; the cylinder varies by maker
Colour
Rockdoor: 14 colours, and the inside can differ. GRP: 30 colours outside, white inside
Mostly white, or a coloured foil
Fitted price
From £1,500 (GRP) and £1,900 (Rockdoor) with us
Usually less
If the back door sits in full view and the budget is tight, uPVC can do the job, and a local window company is the right call for it. Where the door is out of sight, or opens into a kitchen you want warm, the extra for composite buys a heavier door, better locking and a foam core.
Door and frame
The frame is part of the price, and so is taking the old one away.
A composite back door comes with its own frame
Every composite back door we fit is made with its own new frame, to the sizes we take at the survey. The old door and its frame always come out together, however sound the old frame looks, because the new door is made to hang in its own frame.
If your back door has a glass side panel, that’s replaced at the same time. The new side panel has its own frame, fitted alongside the door’s: two frames, put in together on the same day. On a Rockdoor, the outside of the frame can match the door’s colour.
On the day, the old door and frame come out, the new frame goes in, and the door is hung, sealed and trimmed inside and out. A standard back door takes about five hours to fit, and a harder one up to ten, the same as a front door. We take everything old away with us.
Had a back door replaced with a similar looking Rockdoor. Great service and communication from the outset. On the install day the job was completed to a very high standard and the place left as it was found, not a spot of dust.
Ian, Google review, November 2024
Glass and light
How much glass, and how private: the two choices that shape a kitchen back door.
Solid, half-glazed or a large glass panel: light against privacy
A solid door gives the most privacy and suits a back door nobody overlooks. A half-glazed door, or one with a large glass panel like the Windsor, brings daylight into a dark kitchen or utility room. In between sit styles with small windows, like the Manhattan, or one slim panel, like the Aspen.
Then the glass itself. Clear glass lets in the most light. If neighbours or a path overlook the door, privacy glass (free on most Rockdoor styles) or a satin finish lets the light through without a view in. A decorative glass design costs £80–£260. There’s no single favourite among our customers: it comes down to how private the garden is.
On a glazed back door, ask about laminated glass: if it’s hit, it cracks but holds together, so it’s much harder to get through.
Security
The two weak spots we see most on the old back doors we take out.
Keeping the back of your house secure
A back door is usually out of sight, so it needs to hold up on its own. On the old back doors we replace, two things let people down most: the lock’s cylinder and the glass.
The cylinder
Older cylinders can be snapped, which opens the lock from outside. Every door we fit has an anti-snap cylinder and multi-point locking that holds the door at several points round the frame. Rockdoor also guarantee their lock against snapping, for £5,000 (our guarantee guide explains what it needs). If you’re keeping an older door for now, our cylinder comparison explains what to look for.
The glass
On many older doors the glass is held in by beads on the outside, which can be prised off. Rockdoor’s S-Glaze seals the glass into the door, so there’s nothing to remove from outside. Laminated glass adds more: it holds together when it’s hit, and with the steel mesh upgrade it makes a Rockdoor Secured by Design.
Warmth
Rockdoor’s own ratings, from their technical manual.
How energy efficient is a composite back door?
Back doors often open into kitchens, so warmth matters. Rockdoor give every style a Doorset Energy Rating. A is the better band, and B also meets the energy limit for a replacement door in England. These are the ratings for the styles on this page:
Rockdoor styles
Energy rating
Aspen, Manhattan, English Cottage, and the Cottage doors (Spy View or View Light)
A
Windsor, Vogue, Classic, Jacobean, stable doors
B
In Rockdoor’s table, each style keeps the same rating whichever threshold you choose, the low one included. GRP doors have an insulating foam core too.
On a very cold morning, the first places a Rockdoor can feel cool, or show a little condensation inside, are its metal parts: the cylinder, the hinges, an aluminium threshold and the edges where the reinforcement runs. That’s normal. In a kitchen full of steam, an extractor fan helps.
Pets and level access
Both are decided before the door is made, so tell us when you ask for a quote.
Cat flaps and a level step
A cat flap
A cat flap is a Rockdoor option, not GRP. Rockdoor fit it while the door is made, so it has to be agreed at the quote: cutting one into a finished door can weaken it and void the guarantee.
Styles: the Aspen, Indiana, Dakota and Tongue and Groove 5, and the Spy View and View Light versions of the Cottage and Stable doors. Not the English Cottage or the Stable Diamond View.
White or brown
Magnetic, opened by a key on your cat’s collar, or manual
Both lock four ways: open, locked, in only or out only
About £70
Jim and Josh came today to fit a stable door with cat flap to replace our back door and a replacement door on the side of the garage. They took great care fitting the doors…
Adrian, Google review, March 2024
A low threshold
A low threshold costs £20 on either range. On a Rockdoor it’s aluminium and 15mm high, so the step onto a kitchen or laminate floor is nearly level and suits wheelchair access. Being metal, it can feel colder than the taller standard threshold on a frosty morning, but in Rockdoor’s table it doesn’t change the door’s energy rating.
Options
Choosing a composite back door: colour, glass and hardware
Everything is chosen at the design stage, so the price in your quote is the final price.
Every photo is a door we fitted, apart from Pebble Grey, Rockdoor’s newest colour, shown close up. Screens show colour a little differently from daylight. See every colour in our Rockdoor colours guide.
Colour£70 for a colour other than white
Rockdoor’s 14 colours work at the back too, with a different colour inside if your kitchen calls for it: 196 combinations. White, cream and light oak are the usual back door choices, and anthracite grey and black are increasingly common where the windows are grey. With GRP, you choose the outside colour and the inside is white.
Glass design£80–£260 for a glass design on a Rockdoor
Clear or privacy glass comes with most Rockdoor styles. A decorative design, satin included, adds to the price. Choosing glass for a back door
Side panels and toplights£300–£500 per panel
A side panel or toplight brings more daylight into a dark kitchen or passage, on Rockdoor and GRP. Each sits in its own frame beside the door’s.
Handles and hardware£100–£180 for a bar handle on a Rockdoor
Lever handles for a traditional look, or a bar handle for a modern one, in chrome, black, gold and brushed steel finishes.
Laminated glassOptional, priced in your quote
Holds together when it’s hit, so a glazed back door is much harder to break through. With the steel mesh upgrade, it makes a Rockdoor Secured by Design.
Low threshold£20 for a low threshold
For a nearly level step onto a kitchen floor; on a Rockdoor it’s 15mm high. Thresholds and cat flaps
Cat flapAbout £70 for a Rockdoor cat flap
Rockdoor only, on the styles listed above, fitted while the door is made.
Costs shown are what each option adds to the starting price.
What’s included
One price, in writing, before you commit.
What’s included in the price of a fitted composite back door
Your door, made to measure, with its frame
Supply and fitting by Jim and Josh, never a subcontractor
VAT, and removal and disposal of your old door and frame
Your floors protected, and cleaned up before we leave
Certass registration and a compliance certificate, if your door has to be registered under Building Regulations
A 10-year manufacturer’s guarantee
Fitting doors since 2010 and a Rockdoor Trusted Installer since 2015: over 3,000 doors, each surveyed and fitted by us
Fitted, including VAT. The same door costs the same at the front or the back as long as the fitting is the same, and back doors usually come to less than composite front doors, because people choose a plainer one.
Your current back door, one from inside and one from outside, and an idea of what you want: solid or glazed, colour, any extras. No home visit needed to quote.
Within 24 hours
Your design and exact price
A design of your back door, solid or glazed as you asked, with an all-inclusive price by email. No sales calls, no obligation.
Within a week
Survey
Happy to go ahead? A £100 survey deposit, which comes off your final balance. We survey at a time that suits you, evenings and weekends included: we measure up, check the frame and brickwork, and confirm your final quote by email.
3 to 4 weeks
Your door is made
Made to measure, to the sizes we took at the survey.
2 to 3 weeks later
Fitting day
That’s how far ahead our diary is booked. Floors covered, old door and frame out, new door fitted and sealed, lock and handle tested. Then we clean up and show you how it all works.
Had big problems with my 15 year old front composit door . It had dropped, Hinge screws wouldn’t tighten , couldn’t get it lock properly.…srugling to open and shut . not used it for 6 weeks . Been looking at getting a replacement, when i came across jim . What a knight in shining Armour… One phone call , arranged a date to come over . well that day was today ! went above and beyond, proper nice gents . come with all the parts to fix it ..& refurbished were it needed . words can’t express how happy i am . i’m going to replace my old back door soon to a newer design & jim definitely will doing it .. once again jim a very big thank you ( mick ) .
From £1,500 for GRP and from £1,900 for Rockdoor, fitted, with VAT, the frame and taking your old door away included. A simple solid or half-glazed design keeps the cost down.
Why replace a uPVC back door with a composite one?
An old uPVC door can drop and discolour. A composite door is thicker and heavier, holds its shape and colour, and has a foam core that keeps draughts out. The two side by side.
Can I keep my existing door frame?
No. A composite door is made to hang in its own frame, so the old frame always comes out with the old door, and the new frame is part of the price. A side panel is replaced at the same time, in its own frame beside the door’s.
How secure are composite back doors?
Both ranges have multi-point locking and an anti-snap cylinder. A Rockdoor adds S-Glaze sealed glass and PAS 24 certification, and laminated glass makes a glazed door harder still. Where old back doors let people down.
Should I choose a solid or a glazed back door?
Solid for the most privacy; half-glazed, or a large glass panel like the Windsor, for daylight in a kitchen. The Rockdoor Manhattan, with small windows, sits in between. Light against privacy.
Do you fit fully glazed back doors?
No. The most glass we fit in a single back door is a large panel, as on the Rockdoor Windsor. For more glass, look at composite French doors or bifold doors.
Can a composite back door have a cat flap?
On a Rockdoor, yes, on the Aspen, Indiana, Dakota and Tongue and Groove 5, and the Spy View and View Light versions of the Cottage and Stable doors, but not the English Cottage. GRP doors don’t take one. It has to be agreed at the quote, before the door is made: cutting into a composite door afterwards can weaken it and void the guarantee.
Will a composite back door make my kitchen warmer?
The insulating foam core, double glazing and weatherproof seals cut heat loss and draughts. Rockdoor rate each style A or B for energy, and both meet the limit for a replacement door: the Aspen, Manhattan and cottage styles are A, the Windsor and Vogue B.
What is the difference between a back door and a stable door?
A standard back door opens as one piece. A stable door has top and bottom halves that open on their own, so you can open the top for fresh air and keep the bottom shut for children or pets. Our composite stable doors are Rockdoor, from £2,350 fitted.
What colour back door should I choose?
Most people match their windows: white, cream and light oak are popular, and anthracite grey and black suit grey windows. Rockdoor has 14 colours and can differ inside and out; GRP is white inside.
How long does a new composite back door take?
Usually around seven weeks from order to fitting. We quote within 24 hours of your photos and survey on a day that suits you, then the door is made to measure. Fitting a standard one takes about five hours on the day.
Can I buy a composite back door without fitting?
Yes. Outside our area, or have a fitter of your own? We deliver composite back doors across mainland UK. See the online shop or ask for a supply-only quote.
