It pays to pay attention to the structural soundness of your barn

Saturday, January 31, 2015

The financial stresses of recent years may have pushed barn maintenance down the list of priorities. But neglecting it for long can cause serious damage – and even barn collapse

by DON STONEMAN

Look up. Straight up. With high pork prices in the foreseeable future – and porcine epidemic diarrhea aside – the biggest threat to your swine farm's profit and sustainability may be over your head in your aging pig barn.

The attic is likely the most neglected part of your barn as far as maintenance is concerned, and high on a checklist of barn maintenance priorities published on the website of the Prairie Swine Centre and put forward by a number of building and insurance experts. And maintenance hasn't been top of mind for many hard-pressed producers over the last few years.

"The economic reality is that people did what they had to do, but they didn't do anything extra," says Doug Richards, swine specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).

Randy Drysdale, assistant vice-president of loss control at Farm Mutual Reinsurance Plan in Cambridge, a reinsurer for Ontario's farm mutual insurance companies, agrees. "When you are losing money, it is very difficult to keep up with ongoing maintenance. These buildings deteriorate very quickly if they are not maintained."

Lee Whittington, CEO of the Prairie Swine Centre, says the checklist was developed to help farmers with money in their pockets decide how to make the best use of those resources. Rather than invest in "their favourite thing," as is easy to do, Whittington says farmers should make sure that the basics of their operations is covered off, especially since routine maintenance may have been neglected during the financially tough years the pork industry has experienced recently.

There are no statistics on structural failures of pig barns but they do happen and a structural failure threatens the viability of the entire farm. The loss of the structure is only part of the cost involved; there is also expensive equipment in the barn and livestock and the farm's cash flow. (The checklist can be found at: www.prairieswine.com/barn-integrity-assessment-checklist/)

The attic is a particular problem, says retired OMAFRA engineer Frank Kains, who helped develop the checklist. "There will be many barns where people have never been up in the attic."

There might be moisture damage from a leaky roof. Or moisture might enter as the result of failure to properly change the ventilation inlets as weather outside changes, says Murray Elliott, who sells for agricultural builder FGC Limited, Wartburg, Ontario.

Elliott, with 25 years managing barns at the innovative Selves Farms at Fullarton before nine years at FGC, wrote the original draft of the Swine Centre's checklist. He has visited a number of sites where barns have collapsed and damage to the roof trusses from moisture was at least a factor.

Barn managers need to go into the attic with a powerful flashlight and a screwdriver. Leaky roofs can create a lot of damage, but few farmers will go into the attic to check for leaks. Metal roofs expand and contract in the summer heat and winter cold. "Screws pop, seams rust. Flashing wears out," Elliott says. On top of that, failure to manage the air inlets along the bottom of the roof line when weather changes creates another danger.

Air inlets in the eaves are typically closed on the prevailing wind side of the barn and open on the opposite side. But when there is a change in weather and wind – and east winds can be particularly difficult as they often are associated with "dirty weather" – snow can be blown into the attic, literally forming a snowbank at the edge of the barn roof. Melting snow soaks the insulation and it stays wet for a long time, Elliott says. The wet insulation covers the metal plates on the roof trusses which then rust and can fail. The bottom cord stays wet and gets "punky" or soft. "You want to minimize (wet insulation) when you can," Elliott says.

Even on cold, still days, the damp exhaust air pushed out of the manure pits by fans operating for minimum ventilation can rise up the side of the barn, up the eaves and into the attic.

Elliott says the required tools for a farm inspection are a ladder to reach the roof, a step-ladder to enter the attic, a powerful flashlight and a slotted screwdriver and knife for scraping and digging. Moving around in the attic requires carefully stepping on the bottom cords of the trusses, which are usually 48 inches apart; otherwise an inspector can fall through the ceiling. An inspection means looking for "punky" wood in those bottom truss cords by scraping with a screwdriver or a knife wherever blown insulation has lost its loft. If punky wood or rusty plates are found, an engineer should be called in to assess what is necessary to save the structure.

Leaks in a roof that doesn't have a surface covering on the inside are easy to see when the flashlight is turned off. Inspection is more difficult if the roofing material has insulation. Sagging or wet insulation indicates a leak. If water is running down between vinyl-backed insulation and the roof, it will find an exit and damage the insulation, but the hole in the roof will be higher up.

"The take home message is 'pay attention.' If we catch the problems, they are salvageable," says Elliott. "If you call me or any other responsible builder, we can fix it before your barn falls down." He notes that one possibility is replacing truss plates with double-galvanized steel. That costs about $8,000 more on a 2,000-head finishing barn of about 18,000 square feet.

While it's not part of a structural integrity check, proper ventilation pressure is important in keeping moisture out of the attic. Elliott adds that an $80 static pressure gauge is another useful tool for checking if barn ventilation is working properly. There are two types of inlets in ceilings where air enters the rooms: actuated or counterweighted. The counterweighted inlets require adjustment from time to time. A static pressure gauge, costing $80, is a cheap instrument for monitoring a large room. Another solution to keeping "pit air" out of the attic is a chimney on the minimum speed fans. A chimney costs $200 per fan.

What should you look for when checking your barn's structural integrity? On the outside, walk the perimeter of the barn and check the roof. Inside the barn, check the floors, slats and equipment tied to the floors. Look at the ceilings. Peer into the manure pit, without entering. Hairline cracks are normal. Larger cracks are causes for concern and require further investigation.

The pit can be examined by looking into the holes where manure is pumped out, or by shining a flashlight through the slats, says FGC's Murray Elliott. "The gases in there will kill you in two breaths," he warns. If some damage is apparent, remove the manure, vent the pit "and bring in the engineers with the breathing apparatus."

Mutual Reinsurance employs teams that look at structures that mutual companies insure.

Farm Mutual's Randy Drysdale adds that backup power generators are another concern in pig barns, as some are improperly installed too close to flammable building material. "They are often installed up against plywood and we have seen cases where they were about ready to burn through."

Drysdale says Prairie Swine has developed a good checklist, but strongly recommends that expert assistance, perhaps from an insurance company inspector, be called in as a backup to the farmer doing a barn self-inspection. He points out that it is very difficult for people on their own to determine what presents a risk and what does not, particularly where farmers are looking at buildings they work in nearly every day. Insurance advisors walk through a barn with a farmer and see "the things that point towards a risk. Based on the history of claims, we see the patterns," he says. "We can give you an idea of how (situations) match up to a standard."

Cracks in a wall for example, can pose a very different risk, depending on where they are located. If they are in a manure tank wall, and that tank gives way, it is very bad for the sustainability of the barn.

Drysdale adds that it's important for farmers to understand what their individual barn policy covers. Damage from leaks in a roof may not be covered in the same way as damage from seepage, for example. "Everybody's insurance policy is different," he says. It's important to know what is covered and what is not.

While the Prairie Swine checklist focuses heavily on slow-acting water damage to the structure, it also addresses fire hazards, a major problem as far as insurance companies are concerned.

The checklist points to the need for clear access to the barn by firefighting equipment, and a reliable source of water to combat a blaze. It also calls for a fire extinguisher in every hall of a pig barn. That's not just common sense, Drysdale says, but is also a National Fire Protection Association rule that must be respected.

Electrical integrity is another matter unto itself, says OMAFRA's Richards, and the ministry has published information on its website about how to deal with those problems. Barns that have been shut down and re-commissioned need to have wiring replaced from the breaker box into the barn as a minimum. BP

The 2001 barn collapse near Innerkip
Agricultural building experts haven't forgotten the catastrophic barn collapse of a Thamesbend finishing barn near Innerkip in late August 2001. Former OMAFRA engineer Franklin Kains remembers it well. So does farm builder Murray Elliott. He works for FGC Limited, which built the barn in 1989.

The barn manager had been elsewhere on the farm when concrete posts buckled in the manure tank. Pigs were killed, but no human lives lost. As for the cause, Elliott explains that, in 2001, that barn was one of about 15 in the province built with a two-foot-deep manure pit underneath it that drained into an eight-foot deep pit.

Elliott describes that particular manure system as "an odd-ball solution" to a ventilation problem of the time when builders didn't know as much as they do now. Early barn ventilation systems were based upon poultry barns and didn't work well for pigs, he says. Every time the barn operator "pulled the plug" on the two-foot-deep tank and released manure into the lower pit, corrosive gases rose to the pit ceiling and collected there. Those gases corroded the concrete pillars, and the two-foot-deep pit fell into the eight-foot pit, bringing the barn down with it. Kains notes that the concrete pillars were not corroded where they were underneath the liquid manure.

The solution is simply to ventilate the eight-foot-deep pit and the problem goes away, Elliott says. The other similarly-constructed barns in the province have not suffered the same fate.

Elliott notes that, as well, a new building code requirement brought in about eight years ago requires more resistant 32 MPA concrete where it will be in contact with manure. "Ontario has its own building code, which is not a bad thing," Elliott says. BP