Box Frame to support roof (barn conversion)

[SE_2025]

Hi,

I've been asked by a client to produce structural design calculations for a steel box frame supporting roof rafters. The frame functions with the beam acting as a ridge beam, as the original roof ties have been removed. The rafters are supported at both the external walls and the central steel beam.

I’ve designed the frame with pad foundations beneath the columns, and structurally everything appears sound. However, I haven’t previously encountered a project quite like this — particularly with a frame spanning 6.5m between columns and a height of 5.5m. I’d appreciate any thoughts on how Building Control might view this setup.

Initially, I had designed the beam to bear on the existing external walls, but due to the age of the building and the absence (or uncertainty) of foundations, I revised the design to include columns to transfer the vertical loads directly to new pad foundations, 800mmx800mmx500mm deep.

Any feedback or considerations from a Building Control perspective would be greatly appreciated.

Best regards,

 

[noseall]

Hi,

I've been asked by a client to produce structural design calculations for a steel box frame supporting roof rafters. The frame functions with the beam acting as a ridge beam, as the original roof ties have been removed. The rafters are supported at both the external walls and the central steel beam.

I’ve designed the frame with pad foundations beneath the columns, and structurally everything appears sound. However, I haven’t previously encountered a project quite like this — particularly with a frame spanning 6.5m between columns and a height of 5.5m. I’d appreciate any thoughts on how Building Control might view this setup.

Initially, I had designed the beam to bear on the existing external walls, but due to the age of the building and the absence (or uncertainty) of foundations, I revised the design to include columns to transfer the vertical loads directly to new pad foundations, 800mmx800mmx500mm deep.

Any feedback or considerations from a Building Control perspective would be greatly appreciated.

Best regards,

No doubt you have included beam/column connection details as well as bolting details for the timber plate on the top of the beam? Other things to consider are footplates on the foundation pads and insulation details. Are the columns tied into the masonry (via welded drilled cleats) etc, or just butted against the masonry?