Converting a steel barn into an oak frame dwelling

Rosebank Barn is a steel-frame hay and pig barn on private land, just outside Bath.

Bristol-based building company BCMServ were commissioned to convert the structure into an oak-framed dwelling – a Schedule Q planning permission.

The client’s vision was to use oak frames alone to create a-structure-within-a-structure that was both aesthetically pleasing, and structurally sound.

This presented a significant technical challenge.

The original barn was an open-plan structure, never designed to carry a floor load, nor the fabrication or insulation necessary for a residential property. The project ‘s architect recommended that Timberpride, as oak frame specialists, work alongside BCMServ to complete the project.

The Build

Central to the solution was designing a frame to carry the whole first floor and creating the ceilings without transferring any load onto the steel structure, as this was designed to carry the roof alone.

Oak posts were used to create a large fireplace to house a stove and support the principle bedroom above. At first glance, the curved braces around this fireplace appear cosmetic. However, the position of doors and windows at this end of the house made it impossible to brace the structure conventionally. The curved braces to the fireplace surround actually prevent that end of the house from flexing!

The oak chosen for Rosebank Barn is 200 years old. It was sourced from the Clinton Devon estate near Bideford and was hand-selected and graded by Timberpride. This immense estate dates back to William the Conqueror.

By November 2019, the first sections of oak frame had been delivered and installation began. Steve Silcock, BCMServ Managing Director, describes the build as being “in continual design development – right up until the moment that the last peg went in.”

A Change of Plan

When the structure was in place, however, the client decided that the two principal load-bearing oak posts in the middle of the ground floor were obstructing the open living space. He requested that they be removed.

This was not only moving the goal posts – it was removing the posts that were supporting the floor above. Rosebank Barn now presented a second engineering challenge for the team.

All reconstruction had to take place onsite and not in the workshop. In addition, all the joints and timbers had been individually cut and crafted. They were not interchangeable. Extensive reworking was required.

An Invisible Solution

The solution was to transfer the load proportionately to as many new areas as possible, including the steel structure of the barn itself. This would enable the first floor to be ‘suspended’ from different posts and from the frame. The teams installed a pair of specially- curved ceiling braces into the middle of the ceiling joists, so that the posts could act as ceiling bosses. Steel straps then tied the upper level to the foundations.

Work re-commenced at the end of 2019, and Rosebank Barn was completed by the summer of 2020. Once again, the solution was a collaborative process between the Timberpride and BCMServ teams.

Rosebank Barn is a steel shed with a heart of oak

“Now that the beams and structural alternations are in position, they look like part of the original design. They have been absorbed into the overall aesthetic of the building – nothing looks out of place, or an afterthought. You wouldn’t know the living room posts had ever been there.”

Steve Silcock, BCMServ.

BCMServ had the following kind words to say:

“A big thank you to Alec and his team. Together we created a great structure, but I never envisaged it would be such a piece of art. Every oak section, joint and connection were traditionally formed and detailed.

It was a thrill to assemble, and to stand back and admire after each day’s work. What a challenge when our client decided he wished to remove two of the principal posts.

Not a problem. Just another timber-engineered miracle.”