Designing an “L” Shaped Dairy Barn
Loyal Reader DEVIN in BURLINGTON FLATS writes:
“Hello, much appreciate the website and discussions. I am puzzling over a design and haven’t had that ah ha moment yet. Seeking help brainstorming a solution rather than engineered details at this stage of the project. Consistently breezy to moderate wind loads. Moderate snow loads at 42 degree parallel. Seldom extremes of either seen. Looking to build an L shaped dairy barn with both wings about 50′ wide and 160′ long, exact to be determined. Could add interior columns if needed to support LVLs to support the intersecting roofs. Existing buildings, property boundary, and road frontage dictate the L shape. 12′ or 14′ ceilings. Prevailing wind into the armpit of the barns. If both were narrower, I would build two monoslopes shedding away from each other. Not looking to build a skyscraper, and can only reduce roof pitch so much, while trying to not create a glacier of ice requiring attention every winter…Should I raise the wall height of 50′ x 50′ intersection so both gable roofs abut a vertical wall beneath a (gable) roof? Do I build a 50′ x 50′ monoslope? Is heat tape in the valley the solution, or is there a designed solution available? Maybe an unequal roof pitch, steep toward the valley. Perhaps install the steel roof sheets with ribs parallel to the valley so snow can’t jamb, but that would run to each end of the barn. A snow pile in the armpit wouldn’t be ideal, but would be more manageable than shoveling the valley and still having to remove the pile. Do I build one gable roof and then start in with monoslope trusses to abut the other gable. Add some windows to an attic truss and call it an office? Thank you for your time! It’s keeping me up at night. Literally last night.”
Thank you for your kind words. We do try to be both entertaining and informative.
A few thoughts here… raising your intersecting 50′ x 50′ area will result in drift onto and slide off loads onto lower roofs. Probably less than ideal for initial investment. Doing same area as a monoslope will bring some similar challenges plus a very expensive (and tall) truss system. Unequal (dual slope) could be an option, however will again be a more expensive roof system. Running roof steel parallel to valley would be unsightly, require longer roof panels creating waste and would leave a cut end (at eaves) subject to premature rusting. 50′ span attic trusses will be very costly, provide a limited amount of space and require going up and down stairs forever.
If it were my own, I would consider running one 50′ x 160′ portion straight through with a gabled roof and a slope of just under 4/12 (keeping overall truss height to 8’4″ or less to facilitate most economical shipping and easiest assembly onsite). Other leg would valley onto this roof and then use thermostat controlled heat tape to prevent undue snow build up. This solution would be least costly to build and should result in a practical structural design solution.
