Engineering: Humidity and Moisture Effects on Your Barn. Are You Aware?

Friday, October 10, 2008

Moisture buildup can cause your roof to collapse. Barn attics should be checked regularly

by RON MACDONALD & MARK ARMSTRONG

Imagine waking up in the middle of night with a steady drip of water onto your bed. Would you fix it quickly? Would you want to know why it occurred?

Moisture can quickly destroy just about any non-stainless, plastic or concrete component in a swine barn if left unchecked. Roof trusses and other roof components are likely to be attacked by moisture to some degree in all barns. Yet, they are rarely, if ever, inspected.

Moisture can get into the attic by a number of ways; leaks in the roof sheathing; and, more likely, via moisture form the barn itself, penetrating poor vapour barriers, leaky and poorly sealed to the ceiling air inlets, and via exhaust air through the soffit openings.

The consequences are devastating. The entire roof system can fail, collapsing on the animals and workers below. If you think a leak into your bed keeps you up, try a collapsed roof. And to top it off, if an insurance company can prove there was a buildup of moisture in the attic (which is not supposed to be present) then the insurance policy is void.

Walls also require inspection. Any insulated stud or pole system needs to be reviewed for location where rodents and water can get in and quickly repaired. This should be done monthly with a quick walk around.

All attics and roofs should be inspected each spring and fall to ensure no damage has occurred and that the attic is not building up a moisture load. Owners can conduct a preliminary inspection, but any evidence of moisture that is not easily remedied should quickly be followed up with a call to a professional. Too much is at stake to let it go.

The photos show examples of what can cause moisture problems and the end results. BP

Ron MacDonald P. Eng. and Mark Armstrong, P.Eng.  are agricultural engineers with Agviro Inc. in Guelph.