What the Windsor Castle Fire Teaches Old Buildings
On the morning of 20 November 1992, a spotlight left pressed against a curtain set fire to the Queen’s Private Chapel at Windsor Castle. The fire burned for fifteen hours. It damaged or destroyed more than a hundred rooms, including St George’s Hall and the Grand Reception Room.
But it did not destroy the castle. At the far end of St George’s Hall the fire stopped, and the Royal Library beyond it was untouched. The reason is worth understanding if you look after any old building, because it was not the medieval stone that saved the library.
Footage of the fire at Windsor Castle, 20 November 1992.
How the fire spread so far
Windsor Castle is built of stone, and stone does not burn. Many owners of old buildings assume this makes them safe. Windsor shows why that is wrong.
The fire did not travel through the walls. It travelled over them and under them, through the empty spaces that buildings hide. There was no fire stopping in the roof voids and cavities, so once flames got into those spaces they moved freely. The fire reached the Brunswick Tower, ran the length of St George’s Hall and went on into the private apartments. Above the hall was a false ceiling, and below it a void under the floor. The fire used both, passing over and under rooms it never entered, and it got as far as the Chester Tower.
The stone did its job. The problem was everything the stone did not seal. In an old building that means the roof voids, the gaps under floors, the shafts around pipework and the cavities behind panelling. Over the centuries these had been opened up, joined together and left unsealed. A wall can be a metre thick, but if there is an open void running over the top of it, the fire will simply go that way.
This is the most common problem we find in older buildings, and it is almost never the original fabric that causes it. It is what has been done since. A cable is pulled through a wall for an alarm and the hole is never sealed. A suspended ceiling is installed in the 1970s and runs straight over a dividing wall. Pipes are boxed in, creating a shaft from the basement to the roof that nobody meant to create. A heavy old door is eased and repainted until it no longer shuts properly, and it spends most of the day wedged open anyway.
What actually saved the Royal LibraryOne fire break, at the far end of St George’s Hall, had not been breached. It held, and the Royal Library survived. Everywhere the fire had already been, the barriers had been compromised by years of alterations. Compartmentation only works if it is complete. A fire needs one way through, and it will take whichever one you leave it.
You probably do not need to replace your doors
This is where most people who look after a listed building stop reading, and we understand why. The fear is that a fire safety assessment will tell you to rip out your historic doors and fit modern certified ones. That would cost more than the building fund can bear, it would destroy the character the listing exists to protect, and the conservation officer would refuse it in any case. So the whole question gets put off, sometimes for years.
In our experience that is rarely what is needed. A solid old door already offers a useful amount of fire resistance. The right question is not whether to replace it, but what it needs in order to work properly. Usually the answer is small.
Intumescent strips and smoke seals can be fitted into the edge of the door or the frame, and once painted they are barely visible. A latch that does not catch can be repaired. A door that has warped can be adjusted. A closer can often be hidden inside the door. And if a door has to stay open during the day, a magnetic hold-open device linked to the fire alarm will release it the moment the alarm sounds, so the door is useful all day and still closes when it matters. All of this costs less than replacement, and conservation officers are far more likely to agree to it.
The same is true of the voids, which are the bigger risk anyway. Sealing a hole around a pipe or fire stopping a ceiling void is invisible once it is done. It changes nothing you can see, and it costs a fraction of what new doors would cost. At Windsor it would have mattered far more than any door.
The order we recommendFirst, work out where the fire barriers in your building actually are. Second, find where later work has punched holes through them, and seal those holes. Third, look at the doors on those barriers and decide what each one needs, which is usually a seal, a repair or an adjustment. Doing it in this order puts your money where the fire would go, and it keeps both the fire authority and the conservation officer satisfied.
What this means for your building
Windsor had its own fire brigade on site, a salvage plan, and staff who knew the building well. It still lost more than a hundred rooms, because nobody had fully mapped the hidden spaces inside it. Most churches, parish halls and converted historic buildings have the same hidden spaces and far less protection.
A fire risk assessment in an old building is a different job from one in a modern office. It needs someone who understands the law and the building. It should tell you where your fire barriers are, where they have been broken, and what can realistically be done about it in a listed structure. A fire door inspection then tells you what condition your doors are in and what each one needs.
We do a lot of this work in churches and other historic buildings across the North West, North Wales and the West Midlands. If you look after a church or a historic building and you have been avoiding the question because you are worried about the cost, the answer is usually smaller and cheaper than you think.
Protecting an old building?
We provide independent fire risk assessments and fire door inspections for churches, listed buildings and historic premises, and we look for solutions that work with the building instead of against it. If you would like to discuss your building, please get in touch.
Get in touch Heritage & church fire safetyThis article is provided for general guidance and does not constitute professional advice for any specific premises. Any alteration to a listed or historic building may require listed building consent, and the appropriate consents should always be confirmed before work begins. Details of the 1992 Windsor Castle fire are drawn from published accounts, including those of the Royal Collection Trust. Fletcher Risk Management Limited provides Fire Risk Assessments, Fire Door Inspections and Fire Safety Training across the North West, North Wales and the West Midlands.