Open Beam Post Frame Construction
Post frame (pole barn or pole building) design lends itself to a myriad of different design opportunities which can create some truly unique as well as magnificent spaces.
We were recently approached by a client who wanted his 36 foot width post frame building to have a 32 foot long area to be (in his words) “ridge and beam” construction. This would eliminate the roof trusses in this portion of the building.
Least expensive, would be to place a beam running the 32 foot direction supported by the endwall columns every 12 feet. The opposite end of the beams would also need to be column supported. Rafters (aligning with the sidewall columns) would then be installed cantilevering over the top of the beams. Finally, purlins on edge would then go between the rafters to support roof sheathing and other typical roof assembly products.
A bit more expensive, would be to place the supporting beam only at the center of the building (a ridge beam). This would come with a greater investment due to the rafters having a larger span. The balance of the assembly would remain the same.
The beams could be any one of several different products. If remaining exposed, either a solid sawn or glu-laminated beam could be used. While the solid sawn beam might look the most impressive, we are talking about a timber which would have to come from a massive tree. I do happen to have an acquaintance who runs a specialty sawmill in Northern California and cuts beams such as these and ships them all over the world. She sometimes spends months in search of just the right tree for a particular job. Needless to say – she is paid handsomely for her work.
If the beam was to be wrapped with other materials, either laminated veneer lumber (LVL – https://www.hansenpolebuildings.com/2013/01/lvl/) or parallel chord light gauge metal connector plated trusses could be utilized.
Keep in mind, the IBC (International Building Code) is going to require the ventilation of this system above the insulation placed between the roof purlins – unless closed cell spray foam insulation is utilized.
As always, The Ultimate Post Frame Building Experience™ is limited only by your imagination, budget and available space!