Which door material for which job? uPVC, composite and aluminium compared
5th October 2026
As a rough rule, uPVC suits budget replacements and rental properties. Composite suits front doors where the customer wants a door that looks good and is secure. Aluminium suits wide openings, bifolds and modern builds. All three work well when they are specified correctly, so choose the material that fits the job and the budget.
Some jobs need a different answer. A south-facing front door, a house near the sea, a property in a conservation area or a strict U-value target can all change the choice. This guide sets out what to check and which material to use.
What to check on the survey
- Is it a replacement or a new build? Replacement doors in existing homes must meet Approved Document L, Table 4.2. That means a U-value of 1.4 W/m²K or better, or a Doorset Energy Rating (DSER) of Band B. Doors with more than 60% glazing can meet Band C instead. New homes have a limit of 1.6 W/m²K, but Part Q also applies. Any door that is easy to reach from outside needs PAS 24 test evidence. The current version is PAS 24:2022+A1:2024.
- Which way does the door face? A south-facing door gets the most sun. This matters most for composite doors.
- How close is the sea? Much of West Sussex is within 5km of the coast or a tidal river such as the Adur or the Arun. Near the sea, aluminium needs a better powder coat and every door needs better hardware.
- Is the house in a conservation area or covered by an Article 4 Direction? If so, planning rules may limit what you can fit on the front.
uPVC doors
A standard uPVC door has a 70mm frame with galvanised steel reinforcement in the frame and sash. It takes a 28mm sealed unit or a 24mm or 28mm panel. The multipoint lock uses hooks, rollers and a central deadbolt.
uPVC is the cheapest way to fit a door that meets Building Regulations. It is also the easiest to repair. Hinges can be adjusted, and panels and glass units can be swapped out.
Use uPVC for rental homes, HMOs and housing association properties, where low cost and easy repairs matter most. It also works well for back and side doors. Glazed panels used to be the weak point for security, but Hurst’s Securicore panels now have a 4mm reinforcement and carry PAS 24:2022 accreditation.
uPVC is less suited to the front door of an owner-occupied home. Customers often want a door that looks more solid, and a panel door does not insulate as well as a composite slab.
Composite doors
Composite doors come in two thicknesses. A 44mm door usually has a GRP skin over a polyurethane foam core. A 48mm door usually has a solid timber core. Solidor, which we supply, has a 48mm hardwood core inside an ABS plastic skin, fitted in a reinforced uPVC frame. Both types meet Part L with the right glass. The main ranges are tested to PAS 24 and can be supplied to Secured by Design standard.
Use composite for front doors on owner-occupied houses, where the customer wants to choose the colour and glass as well as get good security. Fit a TS 007 3-star cylinder to complete the security spec.
Take care with dark colours on south-facing doors. In strong sun, the outside of a dark door gets much hotter than the inside, and this can make the door bow. Glass Times has reported installers being called back to the same jobs for this reason. Along the Sussex coast, many seafront houses face south. If the customer wants a dark colour on a south-facing door, offer a lighter colour, a canopy or porch, a heat-reflective skin or an aluminium door instead. Note the conversation on the survey sheet.
Aluminium doors
Aluminium is the best choice for wide openings with slim frames. For example, Smart’s Visofold 1000 bifold takes panels up to 1200mm wide and 2500mm high. It has a 102.5mm frame, with a polyamide thermal break between the inner and outer sections to cut heat loss. Aluminium is the usual choice for rear extensions, garden rooms and modern new builds. Aluminium front doors also cope with dark colours in strong sun better than composite doors.
Check four things when you specify aluminium.
- U-value. The Visofold 1000 reaches 1.5 W/m²K with 1.0 centre-pane glass. This passes for a new build (1.6) but not for a replacement (1.4). For a replacement, use the DSER route (Band C for doors with more than 60% glazing) or upgrade the glass. Get the certificate either way.
- Safety glass. Under Approved Document K, the glass in a bifold is in a critical location. Any pane in a door that is wider than 900mm must be at least Class 2 to BS EN 12600. Smaller panes need Class 3.
- Threshold. A Part M low threshold must be no more than 15mm high, with any step over 5mm chamfered or rounded. A low threshold keeps out less weather, so on an exposed coastal site, use a rebated threshold unless level access is required. Also check the door’s tested weather rating. BS 6375-1 lets doors be tested at a lower level than windows, so the door may not match the windows.
- Powder coat. Within 5km of the coast or a tidal river, specify Qualicoat Seaside. Its pre-treatment removes at least 2g/m² of aluminium, compared with 1g/m² for the standard class. It is also tested for filiform corrosion, which BS EN 12206-1 does not require. Filiform corrosion is the thread-like corrosion that spreads under the paint on aluminium near the sea.
Hardware near the sea
Salt air damages hardware before it damages frames. On any door near the sea, use 316 marine-grade stainless steel handles, hinges and keeps, with stainless steel screws. Do not mix metals. Zinc-plated screws in stainless steel or aluminium will corrode. This applies to uPVC and composite doors as well as aluminium.
Planning rules in Brighton, Hove and Worthing
Brighton & Hove has more than 30 conservation areas. About half have Article 4 Directions, which mean houses need planning permission to replace their doors. Flats already need permission. The council’s guidance says it will not normally approve uPVC or aluminium doors and windows in a conservation area.
In The Avenues in Hove, front doors should be repaired or replaced with a copy of the original. Some Article 4 Directions only cover the front of the house. In West Hill, for example, uPVC has been approved at the rear.
This means a Regency terrace in central Brighton may need a timber front door, while an aluminium bifold may still be fine on the extension at the back. Worthing also has Article 4 controls on seafront houses along Marine Parade. Check the council’s maps before you quote, and tell the customer early.
Outside these areas, such as the inter-war semis and bungalows of Worthing, Lancing, Goring and Littlehampton, the rough rule at the top of this guide applies.
Survey checklist
- Building Regulations: 1.4 W/m²K for a replacement (Table 4.2), or 1.6 W/m²K plus PAS 24 for a new build (Part Q).
- Door only: replacing a door in its existing frame is not a controlled fitting under Part L (paragraph 10.6).
- Direction and colour: discuss dark colours on south-facing composite doors.
- Distance from the sea: Qualicoat Seaside, 316 hardware and stainless steel screws.
- Glass: Class 2 for door panes wider than 900mm (Part K).
- Threshold: Part M low threshold, or rebated for better weather protection.
- Planning: conservation area, Article 4 Direction or listed building.
- Paperwork: Declaration of Performance, U-value or DSER certificate, and PAS 24 evidence for the exact door you are fitting.
Order from MLI
MLI supplies uPVC, composite and aluminium doors, including bifold doors, to installers, builders and architects across West Sussex. Delivery is free within 30 miles of our Worthing base. Bring your survey sizes to the trade counter and we will help you choose the right system, finish and hardware. For front doors, use the composite door designer to show your customer the options before you order.
