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.”
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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.”
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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.”
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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.”
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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.
Red Flags for Envelope Damage
If your inspection turns up any of these damage indicators, you may need to investigate
further with a professional envelope consultant.
“The biggest preventive maintenance requirements relate to components that wear out quickly, such as sealants,” explains Ted Sheridan, President of Fishburn Sheridan & Associates Ltd. and Region VII Director for RCI, an international association of building envelope consultants. “They prevent moisture from infiltrating from the outside and slow down related deterioration. That’s a good first step.”
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Look closely at the areas where window frames meet the building to see if the caulking is splitting or cracking. These adhesive failures can lead to insidious leaks that may not be noticeable from the inside, Smith recommends. If your building has wooden window trim, look for signs that the trim is rotting – that usually indicates more wood in the wall behind it has deteriorated, Smith adds.
Some signs indicate more than a need for maintenance. If one of these red flags appears, take immediate action to ensure safety isn’t compromised.
“When you start seeing slates slide off a roof because a 100-year-old copper or iron fastener has weakened, that’s an obvious hazard,” Smith says. “We’ve seen this in schools – talk about a scary scenario. Look for any metal or brick on the ground and concentrations of rust. If anything doesn’t look right, do some further investigation.”
Out-of-place bricks or masonry in an otherwise perfectly straight wall may indicate a structural issue, which is a life safety problem, Sheridan says.
You may see red or brown splotches from rust (which could result from corrosion) or efflorescence, a chalky substance found on masonry and brick that could mean discontinuities in the air barrier or interior vapor retarder.
The location and type of staining can help you narrow down specific concerns, explains Daniel J. Lemieux, Principal and Unit Manager for Wiss, Janney, Elstner Associates. Staining or detectable moisture at interior drywall soffits, blind pockets, lay-in ceiling tiles, and above windows and doors can indicate defective through-wall flashing in clay brick and concrete masonry cavity walls. The same problem in the wall assemblies of architectural precast concrete or a similar barrier-type wall can be a symptom of winter condensation forming on the inboard surfaces of the precast in cold climates or breaches in the perimeter joint sealant and gaskets, Lemieux says.
Watch for characteristic “run-down” staining or other detectable moisture on interior window and door frames, vertical mullions, and inboard glass surfaces, Lemieux adds.
“This is a potential indicator of defects in the installation of interior zone dams, end dams, and seals at frame joinery in exterior window and glazed aluminum curtainwall assemblies that may require de-glazing to properly repair,” Lemieux explains. “If de-glazing and internal repair isn’t an option, it may even necessitate the conversion of internally drained windows and curtainwall assemblies into barrier-type assemblies that will rely on the application and maintenance of exterior joint sealant to resist water penetration.”
Visual wear on dock enclosures
The inside face of a dock enclosure gradually becomes compressed into the door opening and both sides can develop tears, rips, and rub marks. When these signs start to appear, “odds are good that the enclosure won’t last much longer,” Swietlik says.
First Aid for Failing Walls
While it’s important to obtain a permanent repair before your small problem turns into a major failure, you may need a temporary fix to stop water from getting into your building in the interim. However, complex repairs can result in more damage if they’re not implemented correctly.
“If you try to tape or glue something down or patch a hole and you don’t know what you’re doing, there’s a high likelihood that you’ll use something incompatible that either causes additional damage or doesn’t work,” says Smith. “For example, EPDM is very vulnerable to solvents and petroleum-based products, so if you use a solvent to clean it, you’re actually doing more damage that way.”
If you think your masonry is becoming dislodged, Sheridan recommends looking into brick ties that can hold loose bricks in place until a better solution is found. They won’t solve a structural problem if one exists but will keep bricks from becoming fully dislodged and injuring someone in the meantime. Mesh or netting installed on the outside of spalling or loosening brick is also an option.
Consider building rapport with a consultant who can advise you on both maintenance and repairs, Smith recommends. With their help, develop a timetable for inspections, renewing coatings, and performing maintenance tasks.
“The point is to pay attention to your building, have a plan, and implement it,” Smith adds. “Don’t wait until you see a stain on the ceiling before you do something.”
|High-Profile Envelope Failures
Building: Church of the Nativity
Location: Huntsville, AL
Problem: This historic landmark has experienced significant damage since its construction in 1859, including wind damage to the 150-foot steeple in 1956, improper repointing of the exterior masonry walls, water infiltration from the roof, and insect infestation in the wood. A building condition survey revealed the need for a comprehensive restoration program for all three structures on the campus.
Solution: A two-year phased restoration project included repointing and masonry restoration with a lime-based mortar appropriate for a historic structure from this period. The galvanized stamped shingles were replaced with copper shingles and standing seam panels in square and “dragon scale” shapes. Copper was chosen based on its appearance and the use of similar materials on comparable historic buildings in the area.
Building: Hampton Place Condominium
Location: Chestnut Hill, MA
Problem: The condominium association requested an investigation of numerous leaks at their three-building property, as well as recommendations for repairs. Noblin & Associates, which restored the condominium buildings, discovered widespread flashing failures and other construction deficits that led to water infiltration.
Solution: The brick masonry veneer was completely removed and rebuilt, incorporating properly installed flashing and waterproofing.
“This building was the poster child for brick buildings gone bad,” notes Ralph Noblin, President of Noblin & Associates. “It was early 1980s construction. When we stripped all of the brick off of the building, behind it was deteriorated sheet rock and metal studs that were rusting so badly that some of them had to be replaced.”
Building: Glass Factory Condominium
Location: Cambridge, MA
Problem: Several dozen leaks plagued the building, requiring an evaluation of the building envelope to determine the most
appropriate course of action.
Solution: A specification package was developed to restore the outside of the building. It included repairing and recoating the deteriorated concrete, repointing and sealing the brick masonry wall sections, and replacing all of the exterior caulking.
COURTESY OF NOBLIN & ASSOCIATES
Janelle Penny (email@example.com) is senior editor of BUILDINGS.