I Want to Add a Steel Ceiling

This must be my week for receipt of good questions which require lengthy answers in order to do justice to the subject. Here is another one:

DEAR POLE BARN GURU: I have a 42 x 60 with insulation in walls and roof, 26 gauge metal, wood trusses, 10 feet o.c. with 2 x 6 purlins. I do furniture and cabinet work and love the insulation but would like to add the white metal ceiling, to help with the heating, cooling, and lighting. Can I add trusses in between existing ones, and build them underneath the purlins? If so can the white metal span 5 feet for a metal ceiling? CHARLES IN BUTLER

DEAR CHARLES: I would begin by examining the truss engineering – if the bottom chord of the trusses is designed for an adequate dead load (oftentimes this will appear as BCDL on the drawings) of five psf (pounds per square foot) or more, then the trusses are probably capable of handling the added weight of the ceiling plus applicable framing.

If the truss drawings are not available, look for the manufacturer’s stamp on the trusses, it should be on the bottom chord and will give the manufacturer’s name as well as the load the trusses were designed to support.

Not having to add more trusses will be the far most economical and practical design solution.

In the event the trusses are not designed to support the weight of the ceiling, I’d recommend asking the truss manufacturer for a “repair” to upgrade the trusses to be able to support the added weight. If you are unable to contact the manufacturer, a registered professional engineer who is competent in truss design and repair should be consulted to design an engineered repair for you.

Once the load carrying capacity has been determined to be adequate, ceiling joists can be placed at five foot on center between the trusses (using joist hangers), so the liner panels can be screwed directly to them.

Could you add another truss between each of the existing ones? Sure, but it is not probably going to prove to be an easy task as they will need to be maneuvered into place. The ends of each new truss are also going to have to be supported by a structural header placed between the sidewall columns and adequately attached to support the weight.  The design of these headers and their connections should also be done by an engineer.

If the purlins are joist hung between the existing trusses, the new trusses will have to be manufactured so as to afford you the ability to have the bottom chords of the trusses all at the same height. This may not be possible.

Steel ceiling liner panels should be able to span five feet, without significant deflection issues making them appear unsightly.

In addition, Here are some thoughts about the use of steel liner panels for ceilings: https://www.hansenpolebuildings.com/2013/08/steel-liner-panels/

Good luck! And let me know how everything turned out for you!