Internal Door – How to Choose, Measure, and Buy in the UK

What matters most when buying internal doors

Internal doors in the UK are typically chosen by construction, finish, fire rating, and fit dimensions. Most standard doors sold in retail listings come in sizes around 1981 x 762 x 35mm and 2040 x 826 x 44mm.

Before you start comparing products, it helps to understand the four key factors that determine both price and performance. Construction affects weight, durability, and sound insulation. Finish determines whether the door is ready to hang or needs additional work. Fire rating matters for specific rooms and buildings. And size dictates whether the door will fit your existing frame without costly adjustments.

Construction: solid core vs hollow core vs solid wood

Hollow-core doors are the lightest and usually cheapest option. They are suited to low-traffic rooms where cost matters more than sound reduction or durability. Solid-core doors are heavier, more durable, and better for insulation and soundproofing. They are also the standard construction for most fire doors. Solid wood doors offer a more premium natural finish but usually cost more than engineered or hollow-core alternatives.

Finish: pre-finished vs white primed vs unfinished

Pre-finished doors are factory-finished and ready to hang, saving time and avoiding painting or varnishing. White primed doors come with a base coat so you can paint them to match your décor. Unfinished doors require staining or painting after installation.

Oak is one of the most popular finishes for internal doors, offering a natural wood look that suits both traditional and contemporary interiors. White primed doors remain a common choice for those who want a clean, painted finish without the effort of preparing raw wood.

Style: flush, panelled, glazed, and shaker

Buyers often compare flush, panelled, glazed, and contemporary shaker-style designs. Flush doors have a flat surface and a minimalist look. Panelled doors feature recessed sections that add visual depth. Glazed doors include glass panels for borrowed light, making them popular for living areas and hallways. Shaker-style doors have a classic five-panel design that works well in both modern and period homes.

Fire rating: FD30 and FD60

Fire doors are designed to slow fire spread and are usually built with a solid fire-resistant core. FD30 fire doors are designed for 30 minutes of fire resistance, while FD60 products offer longer protection. Fire doors are especially relevant for stairways, kitchens, and garage-adjacent openings. One source notes they are strongly recommended in key household locations, especially in larger homes.

Glazed fire doors are available too, using fire-rated glass systems. These allow natural light to pass through while still providing the required level of protection.

What sizes do internal doors come in?

A commonly cited UK standard internal door size is 1981 x 762 x 35mm. Retail listings also show other common sizes such as 2040 x 826 x 44mm and 1981 x 610mm for narrower doors. Fire doors are often thicker than standard internal doors, with listings showing 44mm, 45mm, or 54mm constructions depending on the rating.

To ensure a proper fit, measure your door frame carefully before ordering. Use the smallest measurement to account for any slight variations in the frame. A door that is too large can be planed down, but a door that is too small will leave gaps that affect both appearance and performance.

How much do internal doors cost in the UK?

Typical internal door-only pricing is about £50–£200 per door, with an additional £30–£40 per door for handles, latch, and hinges. Doorsets can range from roughly £90–£300 for mainstream options, while premium doorsets can start much higher.

Example product pricing from specialist retailers shows internal doors in the £97.99–£189.99 range for many styles, with fire door variants often priced higher. Glazed fire doors and premium prefinished models can exceed £300 in some listings.

Are fire doors mandatory in UK homes?

Fire doors are mandatory in specific rooms and buildings under UK regulations. The exact requirements depend on the property type, the number of floors, and whether the building is domestic or commercial. In many cases, fire doors are required between a house and an integral garage, on escape routes in flats and HMOs, and in some newer builds.

For example, a door leading from a kitchen to a garden may not require a fire rating in a typical house. However, a door between a garage and the main dwelling is usually required to be fire-rated. The rules vary, so checking current building regulations before purchasing is advisable.

Certainty is not always straightforward here. While the general principle of fire doors being required in specific locations is well established, the detailed application depends on local building codes and the specific configuration of the property. When in doubt, consulting a qualified professional is the safest approach.

What is the difference between solid core and hollow core doors?

Solid core doors are heavier and more durable than hollow core options. They provide better insulation and sound reduction, making them a popular choice for bedrooms, bathrooms, and home offices. Solid core construction is also the standard for most fire doors, as the dense inner material helps slow the spread of flames and smoke.

Hollow core doors are much lighter and more affordable. They are made with a thin outer skin over a honeycomb or cardboard-like internal structure. This makes them easy to handle and install, but they offer less soundproofing and are more susceptible to damage over time.

For most homeowners, the choice comes down to budget and the level of privacy required. Solid core doors are worth the extra cost in rooms where noise reduction matters, such as bedrooms and bathrooms. Hollow core doors can be a practical choice for storage cupboards, utility rooms, or other low-traffic areas where performance is less critical.

Are Screwfix internal doors any good?

Screwfix is a common UK DIY retailer often checked alongside B&Q and Wickes. The company offers a range of internal doors at competitive price points, including pre-finished, white primed, and fire-rated options. For basic doors, quality is generally considered adequate. However, for solid wood or fire-rated doors, specialist retailers may offer better value and a wider selection.

As with any retailer, the quality of a specific door depends more on the manufacturer and the construction type than on the store itself. A solid core door from Screwfix will perform differently from a hollow core door, regardless of where it is purchased. Comparing the specifications – core type, thickness, finish, and fire rating – is more useful than relying on brand reputation alone.

For basic doors, quality is adequate, but for solid wood or fire-rated doors, specialist retailers may offer better value.

Which retailers sell the best internal doors?

B&Q lists internal oak pre-finished, solid core, and fire door products, including FD30 options. Wickes offers internal fire doors, including white primed solid core FD30 products. Specialist sellers such as Direct Doors, Doorphoria, Express Doors Direct, Climadoor, and Door Outlet show broad ranges across solid core, glazed, pre-finished, and fire-rated doors.

The UK internal door market is dominated by large DIY chains and specialist online retailers. Top retailer category pages often lack educational content – they sell but do not inform. This gap means shoppers who want guidance on materials, sizing, and fire regulations need to look beyond the main product listings.

Specialist retailers often provide more detailed specifications, including information about core construction, glazing options, and fire certifications. They may also offer a wider range of styles, from contemporary minimalist designs to traditional panelled doors.

How do I choose between glazed and unglazed doors?

Glazed doors include glass panels that allow borrowed light to pass between rooms. They are popular for living areas, hallways, and open-plan spaces where natural light is limited. Frosted or obscured glass can provide privacy while still letting light through.

Unglazed doors offer more privacy and are more common for bedrooms, bathrooms, and utility rooms. They also provide better sound insulation, as glass panels can transmit noise more easily than solid materials.

Consider the placement of the door and the level of privacy required. A glazed door between a kitchen and dining area can make a small space feel larger and brighter. A solid, unglazed door is usually the better choice for a bathroom or bedroom where privacy and sound control are priorities.

Frequently asked questions about internal doors