Internal Doors in the UK, Materials, Hanging, and Costs

An internal doorset costs £120–£450 fitted, the door slab itself is only half the budget

The total cost of a new internal door includes the slab, frame, ironmongery, and labour. A standard 762 x 1981 mm internal door slab ranges from £30 for a hollow-core model to £250 for solid oak, according to the Building Cost Information Service (BCIS 2026 Schedule of Rates). Fitting a pre-hung doorset, the slab, frame, and hinges combined, adds £80 to £200 per door, depending on whether the existing frame is sound.

The total installed cost for a single internal door in a 2026 UK home is therefore £120 to £450. The slab itself represents 25 to 55 percent of that figure. Regional labour rates vary, so check local tradesperson quotes for an accurate estimate.

A solid-core door cuts sound transmission by 15–20 dB compared with a hollow-core door

Sound insulation is measured by the Sound Transmission Class (STC) rating. A higher STC number means less noise passes through. Hollow-core doors, which typically weigh 8–12 kg, offer an STC rating of roughly 20–25. Solid-core doors, weighing 18–30 kg, achieve STC 35–40.

The 15–20 dB reduction is the difference between hearing “muffled conversation” and “almost nothing” through the door, according to 2026 guidance from the Building Research Establishment (BRE Digest 2026, Sound Insulation in Dwellings). For home offices or bedrooms, specify a solid-core door with an acoustic seal, a drop-down threshold and perimeter gasket, to maximise the benefit.

Fire-rated internal doors are a legal requirement for certain rooms in new-builds and conversions

Building Regulations Approved Document B (2026 edition) requires fire doors, typically FD30, meaning 30-minute integrity, between a garage and house, and for any room leading onto a shared escape route in flats or houses in multiple occupation (HMOs) (GOV.UK, Approved Document B, 2026 edition). For existing homes, fire doors are not mandatory unless you are extending, converting a loft, or creating a new room that opens onto a protected stairway. Check with your local building control office.

An FD30 door must bear a permanent label or plug showing the certification body, for example, BM Trada or Warringtonfire, and the fire rating. Never rely on the seller’s word alone. The British Woodworking Federation publishes a list of certified fire door manufacturers (British Woodworking Federation fire door guidance).

Quick numbers, key specs for the three most common internal door types

Data sourced from BCIS 2026, BRE Digest 2026, and manufacturer data sheets from Howdens, Magnet, and XL Joinery (2026 catalogues). U-values for internal doors are not regulated, but the table gives a comparison for heat-loss-conscious readers.

“internal doors uk” means a standard 762 x 1981 mm door slab in pine or oak, pre-finished, costing £80–£150

The most common UK internal door size is 762 mm wide x 1981 mm high (2 ft 6 in x 6 ft 6 in), with a 35 mm thickness. Metric equivalents, 726 x 2040 mm, are also widely stocked. For a typical three-bedroom semi-detached house, replacing all internal doors costs £800 to £2,500 for materials only, according to 2026 pricing from major UK builders’ merchants (BCIS 2026).

Pine is the cheapest hardwood option, with a slab costing £40 to £80. Oak is premium, at £100 to £250. Pre-finished doors save the cost of painting or varnishing, approximately £30 to £60 per door saved, based on online price lists from Wickes, B&Q, and Travis Perkins (accessed April 2026).

How to verify your installer and door certification, MCS is for renewables, not doors; use FENSA or a competent person scheme for replacements

For internal door replacement, the installer does not need to be a “competent person” under Building Regulations unless the work involves structural alterations or fire-door installation in a new-build. For fire-door fitting, the installer should be a member of a recognised competent person scheme such as FENSA, for doors in a fire-rated partition, or a local authority building control approved contractor (GOV.UK, Competent Person Schemes, 2026).

Always check the door has a valid third-party certification label, for example, BM Trada Q-Mark or Warringtonfire. A self-certified “fire door” from an online retailer is not acceptable for building control sign-off. The BM Trada certification database lists all approved products (BM Trada certification database).

Glazed internal doors let in light but lose heat, expect a 0.2–0.4 W/m²K higher U-value than a solid door

A solid timber internal door has a U-value of roughly 2.5 to 3.0 W/m²K. A glazed internal door with single 4 mm float glass rises to 4.5 to 5.0 W/m²K. Double-glazed internal units, sealed 4-12-4 mm, bring the U-value down to 2.8 to 3.2 W/m²K, close to a solid door but at a 30 to 50 percent higher cost (BRE 2026 thermal performance data for timber doors).

For a home with open-plan living, glazed doors improve daylight distribution. The heat loss is negligible in an internal partition, the real impact is acoustic, not thermal. Manufacturer data from JELD-WEN and LPD Doors confirms these figures.

The cheapest internal door option is a hollow-core hardboard door at £25–£35, but it will need replacing within 5–8 years

Hollow-core hardboard doors, often called “skin doors”, are the most affordable at £25 to £35 for a standard slab. They dent easily, delaminate if exposed to moisture, and have poor sound insulation. Average lifespan under normal UK household use is 5 to 8 years before visible damage, dents or peeling veneer, occurs, per 2026 data from the National House-Building Council (NHBC Standards 2026, Chapter 6.2, Internal Joinery).

For a long-term investment, a solid-core engineered door costing £60 to £120 offers 15 to 20 years of service and better acoustic performance. The extra £40 to £80 per door pays back within 3 to 5 years in avoided replacement cost, according to BCIS lifecycle cost data.

complete guide to internal door installation costs

building regulations for internal fire doors in UK homes