The most popular door replacement in the UK for the last ten years is the composite front door. The appeal is simple: composite doors have better appearances than uPVC doors and require less upkeep than wooden doors. A good quality composite front door will last between 25 and 30 years, and will look brand new at the end of it’s lifespan.
You can find composite doors in the Entrance and External Doors section. The other door styles available include uPVC doors, timber front doors, and aluminium doors.
What a composite door actually is
The term “composite” gets thrown around a lot, but the proper definition is a multi-material sandwich, as seen in composite doors:
- A GRP (glass-reinforced plastic) skin on both sides, a moulded panel design and either a woodgrain finish or a smooth finish
- Foam insulation, usually high-density urethane, may have a solid timber rail
- A sub-frame, either timber or steel, provides both structural and locking strength
- Edges that are either composite or solid timber strips, depending on manufacturer
The whole slab is typically between 44 and 48mm thick, which is meaningfully thicker than a uPVC slab (usually 28mm) and on par with a solid timber door.
There are two distinctions worth knowing:
Solid composite vs. foam-filled. We can consider a solid composite door a true composite door. They have a full timber core, and as such, they are heavier and more expensive, but they are better in terms of acoustics. Foam-filled doors have a foam core and a timber sub-frame only around the locks and hinges. This type of door is the most popular choice, and when most installers refer to a “composite door,” this is the type of door they are referring to. Solid composite doors are more durable, and so they are the better choice.
True composite vs. PVC-skinned. A lot of doors sold as “composite” are actually a foam core with a PVC skin. These doors are thinner, have a weaker security spec, and are cheaper. Foam core doors are marketed as composite, but they are not truly composite. These are things to ask when purchasing a door: what is the foam core passport, what is the skin material, what is the slab thickness, and is it PAS 24 certified?
Security
A composite slab is hard to break through and is better at resisting forced entry than most timber doors. Combined with the other factors, the slab and the locking mechanism, it makes for a solid door.
When looking for composite doors, the following should be prioritized:
- PAS 24 certification must be for the entire door set and not just the door slab.
- Multi-point locking – a minimum of three points of locking must incorporate hooks, deadbolts, or a combination of the two, and engage the top, middle, and bottom of the door frame.
- Anti-snap, anti-bump, anti-pick cylinder lock that is rated TS 007 3-star or SS 312 Diamond.
- Reinforced frame at the locking keep – usually, doors fail not at the locking mechanism, but the frame.
- Security hinges that have anti-jacking pins.
- Letter plate restrictor or internal cowl to obstruct tool manipulation via the letterbox.
Of the replacement door specifications, the Approved Document Q includes PAS 24 as the standard for a new build.
Thermal Performance
A composite door’s U-value is generally between 1.0 and 1.4 W/m²K for the door set, depending on the glazing and the frame. This figure is better relative to a single-glazed timber door and is competitive with insulated front doors, regardless of their price.
Glazing is important to note. A composite door that has a large glazed insert (i.e., a half-glazed design or a side light) will have a greater U-value than a solid composite. Glass, being a poor insulator, therefore, has negative impacts on the door as a whole. For this reason, triple-glazed options will be standard on higher-spec doors to improve the U-value.
Ultimately, the weatherseals do most of the work. If a composite door has draughts, it is likely not an issue with the door, but a problem with the seals. The slabs and the frame will have EPDM rubber gaskets, brush seals at the threshold, and a drip detail that is placed under the slab.
Umbrella names in the UK market
The UK composite door market is fragmented, but a few key names dominate:
- Solidor — solid composite (timber-cored), broad colour range, premium
- Rockdoor — heavily marketed, multi-point locking, mid to high price categorization
- Endurance — solid composite, heavier slab spec
- Comp Door — solid composite
- GRP-skinned mainstream brands — Hurst, Distinction, Apeer, etc.
Spec, installation, and warranty come before the brand. A badly fitted Solidor is worse than a Comp Door fitted well.
Colour, style, finish
Composite doors come in any colour. RAL, woodgrain or smooth, frame colour, custom glass, mouldings, and panels.
Two important points:
On north facing elevations, dark colours (black, anthracite, deep blues and greens) hold better. The dark colours (black, anthracite, deep blues and greens) can adversely affect the foam core if exposed to the sun on south facing doors. Most manufacturers warrant against this, but it is important to check the warranty terms regarding dark doors in exposed positions.
Glass and ironmongery also lead to greater costs. The base price is usually for standard glass and basic fittings. All else (numeric pull handles, designer letter boxes, leaded or stained glass) come at a premium.
What it costs
UK fitted prices, 2026:
- Entry level GRP-skinned composite, foam core, standard glass: £900–£1,300
- Mid-range mainstream brand, multi-point locking, decent glazing: £1,300–£1,800
- Solid-cored composite (Solidor, Endurance, Comp Door), standard configuration: £1,800–£2,500
- High-spec solid composite, designer glass, triple glazing, custom colour: £2,500–£3,500+
The cost typically includes the installation of replacement doors. Adding new door openings or making structural changes increases the overall cost.
Common pitfalls
Ordering doors online without viewing them in stores. The colour shown in online images rarely matches the door’s actual colour and the grain texture shown in the images is often deceiving.
Buying a budget composite door and thinking it will be as secure as a more expensive solid-cored door. It won’t be. The complete set must be PAS 24 certified as it is the benchmark test and without it, the door is unverified.
Not upgrading the cylinder. A composite door will fail to meet the security standard regardless of the slab quality. The cylinder is a crucial security measure and will have the greatest impact with the least cost.
Neglecting the frame. No matter how strong the slab is if the frame is weak and splits under attack. A reinforced frame with proper fixings into the structural opening is what stops most domestic break-ins.
A properly installed and well-defined composite door may have a lifespan of 25-30 years. The door slab itself will not age, however, the seals may need to be replaced and locks may require servicing and cylinder upgrades may be needed every 8-10 years. The door slab will last longer than the seals, locks and cylinder.