Doors

 Some time back, I did a blog on door handles, specifically looking at the problem of replacing them in a heritage building. Today I take a step back to look at the door itself. I am writing this blog from my office in a building completed in 1942, at the time the last word in modernism. Every aspect of the design has been carefully considered, with even the precast concrete panels on the exterior scaled to line up with the steel bars in the windows. While most of the renovations over the years have either been very sensitive to the original design, or fortuitously simple, in character with the building, the front doors were not so lucky - clearly somebody thought that an "old" building needed "old looking" doors!

The more recent front door to a modernist building

No doubt, the inspiration for this choice of a panelled door with decorative mouldings came from the building next door, which was built in 1922 and has panelled doors throughout - to the exterior doors and all the internal ones. This is consistent with the classical detailing of the 1922 design.

A five-panel door for the side entrance of a building in the Neo-classical style.

As with most architectural decisions, one is constantly weighing up the aesthetic and the practical (although I agree with those who argue that the aesthetic affects the way we are affected by our environment, even if we respond subconsciously, so is also a practical consideration). So I did a bit of a survey of my building (the 1942 one) to see how the architects designed for the most stringent aspect of any building - fire safety.

A hollow-core door with a glass fanlight

The door to my office (in the photo above) does not need to be fire-rated, so it can be a hollow-core - as the name suggests, this has timber framing around the edge of the actual door, and attached to this on the inside and outside are thin panels of either solid wood, or of some kind of composition board if it is to be painted. This solution is not very sound-proof, and anyway, sound would pass easily through the glass of the fanlight, even if the louvres were tightly closed. This is the least expensive type of door, and is the standard solution to internal doors in most buildings constructed after 1950.

For an escape route (in case of a fire) or as the door between two functions, one of which is fire rated, you would need at least a solid-core door. This is made of a material that will not ignite or disintegrate after being exposed to fire for two hours.  In the building where I have an office, this is the doors to the laboratories; in your home, this may be a door between the garage and the house. In 1942, clearly the fire regulations had not yet evolved to this level, as the doors directly onto the fire escapes have a panel of glass, which would break within a short space of time if exposed to flames. In recent years, glass technology has evolved to create fire-resistant materials, so I am assuming that the original glass has been replaced here with a more modern counterpart.

The door to the fire escape

In 1942, the architects seem to have been conscious of the need to make the detailing of the doors to the outside fire-resistant. From the fire escape, there is a solid door with no glazing and in a very robust frame that would comply with the current two-hour rating. A pair of doors opening into a courtyard uses an older type of fire-resistant glazing - Georgian wire glass - which has a steel mesh cast in to the glass itself. The glass may melt or crack under the heat of the fire, but the mesh prevents it from popping out of its frame, in this way preventing the fire from spreading.

A Georgian wire glass fanlight above a door into a courtyard

While I was taking this photo, a number of my colleagues walked by and were fascinated that I was photographing some random glass. None of them had noticed that the glass had these wires running through - one of the many small design decisions that escape notice, but are vital to our safety and enjoyment of a building.