Interior Door Selection: Styles, Materials and Function

Choosing interior doors is one of those decisions that shapes daily life more than most homeowners anticipate. Whether you're renovating a 1930s semi, fitting out a new-build flat, or reconfiguring a Victorian terrace, the doors you choose affect acoustics, airflow, privacy, and the character of every room. Get it right during a refurbishment and you save considerable cost and disruption down the line.

Key points

• UK Building Regulations Part B (Fire Safety) require FD30-rated fire doors on any room opening onto an escape route in a house with a loft conversion or integral garage.
• Solid core doors (typically 35–44 mm thick) provide significantly better sound attenuation than hollow core equivalents — important for home offices and bedrooms.
• Standard UK interior door height is 1981 mm (6'6"); non-standard heights in period homes can require bespoke sizing or specialist suppliers.
• Glazed internal doors must use safety glass (toughened or laminated) in critical locations as defined under BS 6262 and Building Regulations Approved Document N.
• Door linings, frames, and architrave should be ordered to match wall thickness — typically 90 mm, 100 mm, or 115 mm for UK stud walls.

What type of interior door construction should you choose?

The core construction of an internal door determines its weight, acoustic performance, and how well it takes paint or stain.

Hollow core (cellular or honeycomb fill)

Hollow core doors have a timber frame infilled with a cardboard or lightweight cellular core. They are lighter, less expensive, and easier to handle during installation. Their main limitation is sound transmission — they provide limited acoustic separation. Suitable for cupboards, low-traffic hallways, or budget-conscious projects where noise control is not a priority.

Solid core

Solid core doors use a continuous timber or engineered wood fill. They are heavier and provide measurably better sound insulation — typically 28–34 dB Rw versus around 20 dB for hollow core — and feel more substantial to operate. Usually the right choice for bedrooms, home offices, and rooms adjoining a kitchen or living space.

Solid timber

Fully solid timber doors — often seen in period-appropriate panelled styles — offer good acoustic performance and durability, but can be prone to expansion and movement in homes with fluctuating humidity. Engineered alternatives use a solid timber veneer over a stable core, balancing aesthetics with dimensional stability.

Door styles and finishes

Finishes: most interior doors are supplied primed, pre-finished white, or as bare timber ready for staining. Primed doors require a topcoat on site; pre-finished options save painting time but limit on-site colour customisation.

Fire door requirements in UK homes

Fire doors are not optional in certain domestic situations. Under Building Regulations Approved Document B (Volume 1: Dwellings), FD30 fire doors — providing 30-minute fire resistance — are required:

• Between an integral garage and the rest of the dwelling.
• On rooms opening onto a protected escape route in properties with a loft conversion that creates a habitable floor.
• Between a new extension and the original building in some configurations — check with your building control officer.

FD30 fire doors must carry a recognised certification mark (BM TRADA Q-Mark, Certifire, or similar). Fitting a certified door with incorrect hardware — wrong hinges, absent intumescent strips, or a non-fire-rated latch — can invalidate compliance. A competent joiner or specialist installer should confirm requirements before and during fitment.

Acoustic performance

For rooms where noise matters — bedrooms, home offices, media rooms — consider these factors alongside core construction:

• Door seals: acoustic threshold seals (drop seals) and perimeter compression seals significantly reduce flanking noise at the base and perimeter of the door.
• Frame fit: gaps between door, lining, and frame reduce acoustic performance sharply. Good installation quality is as important as the door specification itself.
• Glazed elements: glass panels in a door reduce sound separation; double-glazed acoustic units are available for glazed doors where noise separation matters.

Homeowner checklist: before ordering interior doors

• Measure each opening accurately — width, height, and wall thickness for the lining.
  
• Identify any openings on escape routes that may require FD30 fire doors (check with your installer or building control officer).
  
• Decide on door handing (which way the door swings) and confirm with your joiner before placing an order.
  
• Check whether glazed doors will fall within a critical zone under Approved Document N, requiring safety glazing.
  
• Confirm door thickness: 35 mm is common for hollow core; 44 mm for solid core and fire doors.
  
• Allow for lead times — bespoke or period-matched doors can take 4–8 weeks from specialist suppliers.
  
• Confirm that all hardware (hinges, latches, intumescent strips for fire doors) is specified before ordering.
  

When to get professional help

Most interior door replacement is straightforward, but professional advice is worth seeking when:

• FD30 fire doors are required — incorrect installation can invalidate the fire rating and breach Building Regulations.
• Structural openings are being widened or repositioned, which may require a structural engineer's input.
• A period home has non-standard door sizes, unusual wall constructions, or decorative architrave that needs careful matching.
• You are installing pocket or bifold doors into existing walls where services (pipes, cables) are unknown.

An experienced joiner or door installer will carry out a site survey, confirm compliance requirements, and source doors suited to your openings.

How Housey can help

If you need doors professionally supplied and fitted, Housey can connect you with vetted window and door installers in your area. Submit a brief describing your door count, any fire-door requirements, preferred style, and wall construction, and receive quotes to compare.

Frequently asked questions

Do I need fire doors inside my home?

You need FD30 fire doors if your home has an integral garage opening into the dwelling, or if you have a loft conversion where rooms open onto the only escape route. Standard like-for-like door replacements elsewhere do not generally require fire doors, but check with your building control officer if you are unsure about your specific property configuration.

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

A solid core door has a continuous engineered fill throughout, making it heavier and significantly better at blocking sound — typically 28–34 dB Rw versus around 20 dB for hollow core. Hollow core doors use a lightweight cellular infill and cost less, making them suitable for cupboards and low-traffic areas where acoustic separation is not needed.

How much do interior doors cost in the UK?

Indicative UK costs, last reviewed 2026-05-26. Hollow core doors start at around £30–£80 each; solid core from £80–£200; solid oak panelled from £150–£400+. FD30 fire doors typically cost £150–£350 before fitting. Allow £50–£120 per door for professional installation as a guide. Bespoke sizes carry a significant premium. Always obtain itemised quotes before ordering.

Sources and further reading

• Building Regulations Approved Document B: Fire Safety (Volume 1, Dwellings) — GOV.UK
• Approved Document N: Glazing — safety in relation to impact, opening and cleaning — GOV.UK
• BM TRADA Q-Mark fire door certification — BM TRADA