Behind the Design – Broadleaf Oak Plank Fire Doors

The CHALLENGE of Oak Plank FIRE DOORS

In the late C20th, building regulations introduced requirements for fire doors in domestic homes. Modern doors with an engineered construction were easily adapted to include fireproof materials in their core. Some solid oak panelled doors were also able to comply with the addition of fire retardant finishes due to their thickness.

Traditional Oak plank doors posed a problem as their design didn’t lend itself to either of these solutions. Workarounds included engineered plank style doors with veneers laid in a plank design over a fireproof core, and blank fireproof doors with thin planks glued to each side, but none of these had the look or feel of a traditional oak plank door.

Many of our customers were converting barns, which typically required fire doors due to the open plan nature of their design, and they wanted traditional style plank doors that looked and felt authentic to these buildings. In true Broadleaf style, we began to experiment to find them a solution.

Broadleaf Oak Plank Fire Doors

Fireproof Core

The challenge was to add a fireproof intumescent core, whilst retaining the traditional construction. Somehow sandwiching a fireproof layer between two sets of planks was an obvious first step, but how to avoid the result being too heavy for traditional hand forged hinges, how to deal with the fact that the fireproof layer would be visible on the side of the door, and how to secure and finish the door without the screws and nails breaching the fireproof core were more complicated.

Many fire retardant materials had to be ruled out many options due to colour – an orange or blue stripe down the edge of the door was not going to help it look authentic or add to its character. Many suitable materials didn’t exist in a size that was suitable for a full size door. Traditional oak planks doors are typically closed using thumb style latches, which rely on a hole being drilled through the door – that wasn’t going to work for a fire door.

Traditional Construction

One by one, we considered the problems and came up with solutions. After several years of development, we came up with a design that worked – traditionally constructed, with a discreet intumescent fireproof layer and all of the same design details as our classic oak plank door, from the bead and butt profile of the planks to the hand-forged cut nails on the face.

Hand-Forged Latches and Hinges

Traditional thumb latches, the most common choice for plank doors, couldn’t be used with fire doors due to the hole that needs to be cut and left exposed for them to work. We sourced traditional hand forged cottage latches and rim locks that could be used as an alternative with the fire door design. These were the precursor to modern mortice latches, designed to be mounted to the surface of a door rather than housed within it and leaving no exposed opening in the door.

Door Liners with INTEGRATED Smoke Seals

We also designed a traditional oak door liner that could house smoke seals – another requirement of a fire door for obvious reasons – and still be made to measure. Given that most of the properties where our plank doors are fitted do not have standard size doorways, this was a key part of the design process.

THE TEST

We held our breath for the fire test, but needn’t have worried – our plank door design achieved 48 minutes, well over what was required for a FD30 or half hour rated fire door.

And so, nearly 20 years ago now, the Broadleaf Oak Plank Fire Door was born. The design has stayed the test of time, and our doors have been integrated into all sorts of exciting projects, from beautiful homes to elegant boutique hotels.