Replacing internal doors in a house


When replacing internal doors in a house, it is important to consider if they perform the function of a fire door, assist with good circulation of air around the house or provided thermal separation between an exempt conservatory or porch.

In most new 2-storey houses, doors between internal rooms do not need to be fire resisting; however, any door between living spaces and an integral or attached garage should provide at least 30-minutes' fire resistance, be fitted with a self-closing device, and have effective cold smoke seals around its edges.

How to identify a fire door

  • there should be, in modern homes, a label fixed to the top edge of the door, which will indicate its fire performance:

fire door label

  • other indicators might be: smoke seals around the door’s edges, and a self-closing device fitted to the door
  • for older fire doors, there might be a small colour-coded plug in one of the side edges, that indicates its fire performance:

colour-coded plug label

Ventilation considerations

Most modern homes will also benefit from whole house ventilation, which relies on small ventilators in windows or walls (background or trickle vents), or passive stacks, or a continuous mechanical extraction, or ventilation and heat recovery system.

In all these cases, the effective circulation of air – via natural draught or mechanical extraction – will rely on air transferring between rooms by being drawn under the bottom of internal doors to effectively circulate between the ventilation device(s) e.g., windows or supply and extract ventilator grilles.

For good air transfer between rooms, replacement doors should have a minimum air gap of 7,600mm2. In many cases, modern house doors are around 760mm wide, which will require an undercut of 10mm (3/8 inches) between the bottom of the door and the top of the floor finish – carpet, tiles, laminate boards etc.

If the home has been stripped of all floor finishes, and the doors are replaced before new carpets or boards are installed, then the undercut should be 20mm (3/4 inches) high, to allow for the thickness of a new carpet, floor tile, or board finish afterwards. A lack of a suitable undercut could affect the ventilation and lead to poor air quality, excessive condensation, and in some cases, mould growth.

You must contact Building Control if...

  • you are removing or replacing doors between an exempt conservatory or porch. This is controlled and notifiable building work as it could be classed as: a material change of use, a change in the energy status of the conservatory or porch, or the provision of a controlled service or fitting
  • you are removing or replacing any internal fire-resisting door. This is controlled and notifiable work as it is classed as a material alteration of the building

For any of these cases you must discuss your proposals with your local authority Building Control team as soon as possible, to ensure the work will comply with the Building Regulations.

You don't need to contact Building Control if...

You are replacing the internal doors in a house (other than fire doors and doors between an exempt conservatory or porch). This is not notifiable or controlled work but any work must not make the conditions of a home worse than they were before the work was carried out and you must ensure that you maintain good ventilation standards.


Please Note: Every care was taken to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the dutyholder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.


Replacing Internal doors

Submitted 1 month ago

Does changing an internal door between a lounge/kitchen and an internal hallway inside a residential flat require the replacement door to be upgraded to be fire resistant if the original isn’t.

LABC response

Submitted 3 weeks 6 days ago


Thank you for your recent question relating to replacing internal doors in a flat. The article was specifically regarding replacing internal doors in a house and we are conscious that replacing internal doors in flats can be a little more complicated, because of fire safety standards.

We note you say the doors are not fire doors. If this is the case then like-for-like replacement with a similar style of door would be acceptable, having regard to the pointers given in the article. We would suggest caution though, since most flats built since the 1950s-60s were required to have fire rated internal doors to living/cooking accommodation and internal hallways, having either 20-minutes or 30-minutes fire resistance.

Whilst fire doors in modern flats do not require a self-closing device or smoke seals (although some specially designed flats could have these features), the door may still be a fire door and we recommend a check be carried out to establish if the door has the appropriate fire door identification, like the ones we highlight in the article.

If you are not the first occupant of the flat, it might be that some or all the doors could have been changed by previous owners and who might have replaced fire rated doors with non-fire rated doors. We also recommend that you speak to your landlord, since the internal hallways of flats can often have a link to the fire protection of the common corridor/lobby or staircase. The landlord might have more information on the how the building was constructed and whether the internal flat hallways have been designed/constructed as a ‘protected entrance hall’.

If the door was intended to be a fire door and no longer is, we recommend that the door(s) be replaced with a door to the same rating as was intended for the building, which is likely to be either a 20 or 30-minute rated fire door – that is to say one that is rated as either FD20/FD30, or E20/E30.

LABC team

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