Composite Front Doors London & Surrey | Supply & Fit | Window Fitters Ltd

Composite Entrance Door Supply and Installation

Window Fitters Ltd supplies and installs high-security composite front doors for residential homes, new-build developments, and refurbishment projects across Greater London, Surrey, and the South East. Our composite doors combine high-density insulating cores, impact-resistant glass reinforced plastic (GRP) outer skins, and multi-point hook locking systems to deliver outstanding thermal efficiency, weather resistance, and forced-entry protection. Every doorset is measured on site, manufactured to exact opening tolerances, and fitted by our directly managed, CSCS-certified glazing teams.

Whether you need a classic Victorian four-panel entrance, a 1930s style with decorative glazing, or a sleek contemporary flush slab with long architectural pull handles, our composite doors satisfy current UK Building Regulations for insulation (Approved Document L) and security (Approved Document Q and PAS 24).

Slab Construction: Solid Timber Core vs Polyurethane Foam

Composite door slabs are engineered using multi-layer construction designed to overcome the common weaknesses of traditional timber and single-skin uPVC doors. Two primary core constructions are available:

The outer face of both slab types is compression-moulded with a 2 mm to 4 mm GRP skin featuring an authentic through-colour woodgrain texture. Unlike painted timber, GRP does not absorb moisture, crack, or rot, eliminating regular repainting. Routine cleaning with warm soapy water is all that is required to maintain its finish.

Multi-Point Locking Mechanisms and PAS 24 Security

Security is the primary consideration for any external entrance door. Our composite doors are equipped with multi-point espagnolette locking systems that secure the door leaf into reinforced steel keeps inside the outer frame at multiple points along the full height of the opening.

Standard security specifications include:

• Heavy-duty steel hook bolts: Top and bottom high-tensile steel hooks engage upwards into the outer frame, preventing the door slab from being levered or jemmied open with a crowbar.
• Central deadbolt and latch: Engages securely in the middle keep when the handle is lifted or when key-operated slamming mechanisms engage.
• TS007 3-star anti-snap lock cylinders: British Standard Kitemarked cylinders engineered with sacrifice cuts, anti-drill pins, and hardened steel bridges. These resist snapping, picking, drilling, and bumping attacks, meeting the requirements of Approved Document Q for new residential dwellings. Learn more in our PAS 24 security guide.
• Dog bolts on hinge side: High-tensile steel studs fixed to the hinge edge of the door leaf that slot directly into the frame rebate when closed, securing the door even if the external hinge pins are attacked. Explore our door locking hardware.

Understanding Thermal Bowing in Composite Doors

Thermal bowing is a natural physical characteristic of composite doors, particularly slabs finished in dark colours (such as Anthracite Grey RAL 7016 or Midnight Black) on south-facing or west-facing elevations exposed to direct sunlight. The exterior GRP skin absorbs solar radiant heat and expands, while the internal skin remains at room temperature, creating a temporary temperature differential that can cause the slab to deflect slightly outward at top and bottom (typically 2 mm to 4 mm).

High-quality composite doors are engineered to tolerate this thermal movement without permanent deformation. To prevent long-term deflection, always throw the handle upwards to engage the top and bottom hook locks whenever the door is closed, even when you are inside the house. This keeps the slab pressed firmly against the outer compression seals. When the sun moves and the outer skin cools, the slab returns to its true plumb alignment.

Threshold Types and Part M Compliance

The threshold is the bottom sill component over which you step when entering the property. Choosing the right threshold depends on weather exposure and accessibility needs:

• Standard thermally broken aluminium threshold (44 mm upstand): Provides maximum weather tightness and driving rain resistance, featuring internal thermal breaks and dual compression gaskets. Recommended for open, exposed elevations.
• Low-profile Part M compliant threshold (15 mm upstand): An ultra-low aluminium sill designed for step-free wheelchair, pushchair, and reduced-mobility access in compliance with Approved Document M. Check our Part M threshold guide.
• Stormguard integration: Fitted with twin nylon weather brushes and concealed drainage channels that route wind-driven water back outside.

Styles, Colours, and Architectural Hardware

Our composite doors can be configured in a wide variety of styles and colours to suit traditional, heritage, and contemporary architecture:

• Traditional designs: 2-panel, 4-panel, and 6-panel layouts with Georgian fretwork, arched top glazing, or diamond bevels, ideal for Victorian, Edwardian, and 1930s suburban homes.
• Contemporary designs: Flush slab designs with offset glazed cassettes, vertical grooves, and full-length stainless steel bar handles.
• Standard colour palette: Anthracite Grey (RAL 7016), Slate Grey (RAL 7015), Chartwell Green, Midnight Black, Rich Navy, Duck Egg Blue, and Golden Oak.
• Architectural hardware: Premium solid brass, brushed satin, chrome, and matte black handles, letterplates, Victorian urn knockers, and spyholes.
• Glazing options: Obscure backing glass (Pilkington Level 1 to 5 textures), acoustic laminated glass for road noise reduction, and toughened safety glass conforming to BS EN 12600.

Technical Survey and Structural Opening Inspection

Every entrance door replacement begins with a detailed on-site technical survey conducted by an experienced surveyor within our 40-mile service radius from Croydon:

• Three-point measurement: Measuring structural brickwork width and height across top, middle, and bottom positions, deducting a 10 mm overall expansion tolerance to ensure a square, plumb installation.
• Lintel inspection: Checking the condition of the masonry lintel above the opening to ensure no structural settlement loads are bearing down on the door frame.
• Sub-floor and reveal condition: Inspecting the internal plaster line, existing sub-cill projection, and floor levels to determine threshold requirements and sub-cill depth (e.g. 85 mm, 150 mm, or 180 mm).
• Safety glazing checks: Confirming that all sidelights and low-level glass conform to Approved Document K safety standards.

What Happens on Installation Day

A standard single composite front door replacement takes approximately 3 to 5 hours for our 2-person glazier team:

• Careful removal of the existing door leaf, outer frame, and cill without damaging surrounding interior plaster or exterior brickwork.
• Positioning the new heavy-duty reinforced outer frame in the structural opening, using spirit levels to achieve exact plumb and level alignment.
• Fixing the frame into brickwork using direct frame fixings spaced 150 mm from corners and no more than 600 mm apart.
• Insulating the perimeter cavity around the frame with low-expansion polyurethane foam to eliminate cold draughts.
• Hanging the composite slab on heavy-duty 3D adjustable hinges, fine-tuning lateral and compression alignment against frame gaskets.
• Fitting glazed cassettes with internal security glazing beads, installing door furniture, and setting up the multi-point locking keeps.
• Applying external perimeter low-modulus neutral-cure silicone sealant and internal finishing trims.
• Demonstrating door operation, locking procedure, and handing over warranty documents and keys.

What Affects Composite Door Costs

The total investment for a replacement composite front door depends on specific specification choices:

• Core type: Solid timber core slabs carry a 15% to 25% premium over standard foam-filled cores due to material density.
• Glazing complexity: Elaborate decorative triple glazing, stained glass, or acoustic laminated cassettes add to the unit cost compared to unglazed solid slabs.
• Sidelights and top fanlights: Adding matched double-glazed side screens or an arched top light requires additional frame couplers and structural glazing.
• Hardware upgrades: Long architectural pull bars, motorized keyless access systems, and bespoke letterplates.
• Structural brickwork alterations: Widening an existing entrance or installing new catnic steel lintels.

For a detailed breakdown of residential pricing factors, read our window and door cost factors guide.

Care, Maintenance, and Hinge Adjustment

Routine care ensures your composite door operates smoothly for decades:

• Hinge adjustment: If the door leaf drops slightly over time, our 3D adjustable hinges allow quick lateral (+/- 2 mm), vertical (+/- 3 mm), and compression (+/- 1.5 mm) adjustments using a standard Allen key.
• Lock cylinder lubrication: Apply dry graphite powder or dedicated lock lubricant into the keyway once a year. Never use WD-40, multi-purpose oils, or heavy grease, which attract dirt and gum internal cylinder tumblers.
• Multi-point gear care: Spray light silicone lubricant onto the locking hooks, deadbolts, and faceplate gears twice a year to maintain smooth handle movement.
• Gasket and skin care: Wipe down rubber weather seals and GRP door skins with warm soapy water every six months to remove atmospheric traffic grime.

Supply and Fit or Labour-Only Options

We provide two flexible contracting routes across London and Surrey:

• Supply and Fit: Comprehensive turnkey package including site survey, bespoke UK factory fabrication, delivery, removal of old door, installation, perimeter draughtproofing, and a 10-year manufacturer-backed frame warranty. Explore our supply and fit services.
• Labour-Only Installation: Professional fitting of client-supplied composite doorsets to manufacturer tolerances by our CSCS-carded installers. View our labour-only installation services.

Book a Survey and Itemised Quotation

To arrange a technical measurement survey across London and Surrey, call Window Fitters Ltd on 020 3411 0589 or submit your details online via our quote request page.