Water infiltration is the biggest culprit in envelope failures, but its causes range widely. Frequently the result of multiple factors converging over time, leaks can take years to show up – and if you can see water on the inside, significant damage to your envelope is likely.
“By the time water shows up on the inside of your building, it’s had to pass through a lot of materials to get there,” explains Michael Smith, a design consultant for Wheaton Sprague Engineering, a professional services practice focusing on facades, envelopes, and curtainwall.
Repairing a damaged envelope becomes costly very quickly. Stop pending exterior failures in their tracks by spotting them early and taking appropriate action.
5 Reasons Why Exteriors Fail
“All areas of the building are susceptible to different types of failures, but the building envelope in particular comprises most of the failures we commonly see,” explains Dustin Smoot, Department Manager of the Forensic Sciences Group for Pie Consulting & Engineering. “Knowing the causes of the failure can help you monitor the building to prevent a catastrophic event.”
If you’re not keeping an eye on trouble spots and early symptoms, you may not discover a slow leak until considerable damage is done. Deficiencies like the ones below can build on each other to exacerbate an issue.
1) Thermal expansion and movement: “One big problem that we see repeatedly is a lack of accommodation for thermal expansion and contraction,” says Warren French, President of French Engineering, a specialty engineering firm focusing on roofing, waterproofing, and curtainwall. “Nature will do a good job of opening joints and cracking materials, whether they’re stone, cladding, or masonry. Movement leads to cracking, which leads to water intrusion that overwhelms the flashing systems.”
This problem is particularly pronounced in areas like the Midwest where wide temperature variations can wreak havoc on improperly flashed buildings, says Bill Derrick, President and CEO of Derrick Building Solutions.
“Our temperatures can vary from -30 to 100 degrees F.,” explains Derrick. “That can wear on joints around walls and wall openings. Many of the failures we find are around openings in the walls, such as windows and doors, that weren’t properly flashed when installed.”
2) Improper specification: Areas like docks have special needs depending on the type of building they’re attached to, explains Walt Swietlik, Director of Customer Relations and Sales Support for Rite-Hite, a manufacturer of loading dock equipment. That’s why it’s imperative that you make your designer aware of how you’ll use the space.
“The most common problem is specifying the wrong size of dock door, which can lead to all kinds of contamination issues,” Swietlik explains. “The same thing happens with types of dock enclosures – the client will specify the wrong type for the way they intend to load and unload trailers. Far too often, we see clients who need access to the back of a trailer. They want to be able to open the building door and see nothing but the trailer’s walls, floor, and ceiling, which would normally require a dock shelter for the trailer to back through. Yet they’ll specify a dock seal – an enclosure that seals tightly and creates a gasket between the outside of the building and the trailer – even though it will significantly limit access to the back of the trailer. Forklift drivers hit the product and it fails prematurely.”
3) Drainage areas: Wherever water drains, leaks can occur. This is especially true along the top of the building, which shoulders the largest share of storm damage.
“If a building has gutters and downspouts, those are probably the No. 1 reasons we have leaks and failures,” says Smith. “That’s due to a combination of being under-designed, the amount of rain drainage, or most commonly, a lack of maintenance and routine inspections. Gutters and downspouts get clogged and are prone to wind damage.”
Buildings with a collection-and-weep system (internal drainage that allows water to enter and exit masonry and stone) require floor-to-floor flashings that collect and expel water. However, the flashings may not be properly integrated with other components and weeps must remain unobstructed, French adds.
4) Construction defects and poor repairs: Joint seals and transitions are especially vulnerable to deferred maintenance and poorly executed repairs. One case Smith tackled involved an expansion joint for a gutter on a century-old building. Smith determined where the joint should be, but when he went to find it, the joint was missing.
“Somewhere along the line, a maintenance person decided to take it out when they didn’t have the money to repair it,” Smith explains. “In doing so, water flowed in different directions, and all of a sudden gutters that weren’t intended to handle that much water were getting more than they should.”
5) Incompatible materials: Watch out for compatibility issues with repair materials, Smith says. Heading to a home improvement store when you need caulk can backfire, as big-box stores generally don’t sell the high-performance caulk used in commercial construction and your purchase may be incompatible with the existing building.
“People also don’t think about incompatible metals,” adds Smith. “If you put galvanized steel across a copper roof to extend a downspout, the copper will eat the less noble metal. If you’re doing maintenance, use compatible materials, and if they’re not compatible, separate them.”
Intercept Issues with Inspections
Inspect your building at least twice a year, preferably after winter and summer, and immediately following high winds or storms that could have caused damage, French recommends. Look for cracks, wear and tear on sealants and paint, and cladding or siding that appears to be detaching.