By SMT Research.

Understanding what potential damages there are and having strategies to either prevent or repair those damages on rooftops is critical to roof longevity.

From initial designs on napkins, through to blueprints and shop drawings, it is easy to imagine buildings being constructed as perfectly as they are drawn. While the resulting structures can be magnificent, the construction process is one of complex logistics and timelines subject to external factors such as the weather, the economy and supply chain issues. As the roof system is assembled over the course of months if not years, there are myriad ways in which that roof system can be damaged during construction. Some of these damages are unavoidable, however others might be addressed through education or action. 

The modern roof is not just a shelter for the occupants of the structure, but also a platform for amenity spaces such as gardens, basketball courts and even daycare centres. Additionally, the roof is home to essential building mechanisms such as heating, ventilation and air conditioning, as well as a space for water storage, solar power generation and even helipads. All of these assets require the work of multiple trades to install, and while they perform vital functions or add significant value to the building, they also create opportunities for damage to the waterproof membrane meant to keep moisture from getting inside. 

Above: penetrations found in one membrane over multiple leak detection scans

What causes leaks? 

Generally speaking, manufacturing quality and installer craftsmanship are not to blame when leaks occur. Membrane manufacturers design their products with great care and rigorously before taking them to market accompanied by clear best practices for installation. Roofing contractors know their trade well and take great pride in their workmanship, doing their best to complete roofing systems with defect-free membranes. 

The main culprits for leaks and water damage on newly constructed roof systems are construction sequencing, and damage done by other tradespeople. These two factors combined make up the majority of damages found on large commercial flat roofing systems, the following table summarizes our findings when scanning roofs - with an average of 5.1 penetrations of the waterproof membrane per thousand square feet scanned. 

Above: chart reflecting the source of damages to waterproof membranes found during leak detection scans

Types of roof assembly

Large flat low-slope roof assemblies usually fall into two categories; conventional or inverted. The simplest way to understand the difference is to observe where the waterproof membrane sits within the layers of the roofing system. On a conventional roof assembly, the waterproof membrane is the top-most layer, capping the assembly and in theory sealing the roof from the elements. On an inverted (sometimes called protected) roof system, the waterproof membrane is far lower in the assembly - either installed directly onto the wood/concrete/steel structural element of the roof or else on top of a levelling layer. On both conventional and inverted roof assemblies the membrane is intended to be a monolithic layer without breaches (except for drainage or conduits), however in both cases there are many ways in which the exposed membrane might be damaged during construction - all of the risks mentioned in this article are applicable to both types. 

Unavoidable damages

Walk through any city and you are bound to see tens of cranes lifting heavy equipment and materials onto under-construction buildings. The rooftop is a busy hive of construction activity, and must be made safe for the people at work. Safety fences must be secured to the low-slope roofing, and are generally ‘mechanically fastened’ using screws or nails which penetrate the membrane on the parapet or in the field of the roof. These penetrations can be found afterwards using a leak detection scan, and must be patched before the roof system can be considered complete. 

Also unavoidable is the payload of all those cranes; everything from bricks and mortar to AC units and glazing units must be lifted onto the roof before they are installed in the upper floors and rooftop. By necessity, as inner-city projects often don’t have off-site storage, the rooftop becomes a construction ‘staging area’ where materials are kept. These materials can cause compression or else penetrations into the membrane if stored incorrectly, with the weight of the materials not dispersed over a wide enough area. A dolly might be useful for transporting equipment across the site, however if left for a prolonged period the weight of the material can press the wheels of the dolly into the membrane - causing damage that may go undetected. 

Above: inverted rooftop assembly used as a staging area while the membrane is still exposed

While it is not a factor during construction, it should be noted that all building products naturally deteriorate with time - an unavoidable fact. Furthermore, the roof is perhaps the most exposed structural element of a building, taking damage from the extreme temperatures and weather events as well as human activity over the course of its lifespan. This makes it all the more important that risks to the membrane are properly accounted for so as to get the maximum value out of the roof system. 

Avoidable damages

Having performed leak detection scans on thousands of large low-slope roofs we have seen a multitude of ways in which the membrane has become damaged. Many of these are avoidable through training or else risk mitigation strategies. 

A rule of thumb that can be applied across any site is treating the waterproof membrane as a finished product that ought to be protected - just as windows and stainless steel elements being covered by protective layers until construction is complete. For membranes, using a night seal to protect the roof assembly prior to completion is a basic and effective method. The use of the membrane as a staging area is often unavoidable, however using designated walkways over coverboard as well as storing equipment on pallets that distribute the weight are good ways to protect the membrane.

On conventional roofs in particular we see issues of construction moisture being sealed within the membrane - often from work not being complete within a day and then the night-seal failing (generally due to improper installation) allowing water from rainfall to seep under the incomplete membrane. The most common way that moisture can get into the roofing system is parapet walls being left open - with the work performed by other trades whose timeline may not align with the roofing contractors. The best solution here is education; the roof should be looked at holistically as a single system that is not complete until sealed both on top and from the sides. 

One project that was under construction during the winter months saw a membrane exposed to an overnight deluge of rainwater which then froze - coating the membrane in several centimeters of ice. We returned to site to see several contractors working with jackhammers to break the ice and access the membrane in order to place down insulation. This was a simple matter of the contractors not understanding the damage this could cause to the membrane, damage which was confirmed when a leak detection scan was performed. Education from the manufacturer or a site supervisor would eliminate this unnecessary damage. 

Damage or risk to the membrane is often detected during construction, leading to re-work as trades remediate the issue. This was the case when a roof component had been installed incorrectly and needed to be replaced. During this re-work, the membrane is used as a staging area during efforts that were not part of the original construction schedule and therefore may be under significant time pressure - causing defects through rushed work. This can be resolved through greater care and attention being given to the storing of materials during work on an exposed membrane, and ideally requiring a leak detection scan prior to the re-covering of the membrane. 

A memorable project caused some head-scratching as leak detection scans found multiple holes around the windows and doors across the site. Eventually it was understood that the primer used to apply protective blueskin onto vertical surfaces had dripped down onto the roof; primer is a solvent which burns through the membrane. On another site we saw chemical damage from 10 litres of gasoline spilled by landscapers as they were putting finishing touches to a green roof. The gasoline pooled in an area with no drainage, and ate through the membrane. While a relatively rare occurrence, these chemical damages to the membrane are avoidable by simply putting down drip cloth before using primer, as well as clearing up any spill that happens on site. 

Above: Chemical burns on the waterproof membrane from primer

On green roofs, we have seen issues on multiple sites where landscaping elements have been inadvertently pushed under protective layers - this was especially prevalent where new details had been added or rework performed after the overburden had been applied. Small stones and other landscaping elements that end up under insulation or drainage matts are compressed by the weight of overburden into the membrane - creating deficiencies or penetrations that lead to leaks. This is avoidable by taking care to ensure any area excavated for additional construction be made clear and tidy prior to work being carried out, with a verification scan as well as a visual inspection prior to recovering.

Intentional penetrations 

Not all penetrations of the membrane are accidental. HVAC units, vents, piping, roof lights, gas lines, drains; all of these puncture the membrane of the roofing system. It is very common for the membrane to be penetrated by forming nails used for creating concrete elements such as planter walls, curb separations etc - generally these are repaired once the work is finished (many are missed, only to be found by an electronic leak detection scan as part of quality assurance). These are of course common and essential elements of the structure and are designed to be watertight to prevent moisture entering the roof system - however in a practical sense they are the most obvious vulnerabilities to the membrane. Due to construction sequencing, these elements are often installed after the roofing contractor has completed work, meaning there is no “advocate” for the health of the membrane present. The best protection for the membrane is to install a leak detection system, which can be used to verify the health of the membrane from the moment it is installed. Furthermore, during installation and subsequent scans, the leak detection install team will document the condition of the roof, with particular attention paid to these potential problem points - generating photos, videos, and reports that can be invaluable in future leak investigations. 

Above: the tape lines around the base of this support column are sensors that isolate this vulnerable area where the membrane has been deliberately punctured, for future monitoring

Conclusions

The roof is a critical building system that requires skill and attention to install. Throughout construction, the waterproof membrane is vulnerable to damages in many ways - some of which are either intentional or unavoidable. There are other damages which we find on almost every roof we scan, and these are absolutely avoidable. The risk of all damage types to the membrane can be mitigated through proper education and planning - understanding what potential damages there are and having strategies to either prevent or repair those damages. The absolute best protection for the roof membrane is to have a leak detection system installed, which can scan the membrane throughout construction and the operational life of the structure. In addition, a leak detection system install team will create a historical report of the roof condition during construction, that can be invaluable to building owners at a later date as eventually all roofs will require attention. 

By SMT Research.

Advanced monitoring systems are changing the game for green roof sustainability.

Green roofs have become synonymous with sustainable architecture, offering a blend of aesthetic appeal, energy efficiency and environmental benefits. But beneath the lush greenery lies a crucial yet vulnerable component — the waterproof membrane. When leaks occur, the cost of detection and repair can skyrocket, threatening both the integrity of the building and the longevity of the roof itself. The solution? A cutting-edge approach from SMT Research that combines technology and real-time monitoring to safeguard these rooftop assets from hidden risks.

The risk  

In nearly 20 years of structure monitoring, we have found common issues that risk the integrity of large low-slope roofing. The majority of these issues occur as damages to the waterproof membrane during construction. The roof deck is used as a walkway, a staging area for materials and equipment and is open to damages from above.  

We have seen:

• Nails and other building materials embedded in the waterproof membrane.  
• Chemical burns as adhesives used on walls and planters drip onto the membrane.  
• Heavy equipment and scaffolding stored on wooden blocks digging into the protective waterproof barrier.  

All these damages allow water into the roof deck where it can cause structural damage, disrupting the operation of the building and costing owners thousands, if not more, in repairs.  

Above: Damages found in waterproof membranes during construction (Credit: SMT)

What is a leak detection system?  

A leak detection system monitors the health of the waterproof membrane which covers the structural roof deck on a large low-slope roof. Advanced low-profile sensor elements are permanently installed directly on top of the waterproof membrane and connected to monitoring electronics. This system can monitor the health of the membrane from the moment it is installed, through construction as layers of insulation and vegetation are placed on top.  

Above: FutureCast Leak detection system installed within the layers of an inverted/protected roof assembly (Credit: SMT, Go2Productions)

The value of a leak detection system on a green roof is that the now-hidden waterproof barrier can be actively monitored for potential leaks, generating reports that guide building owners on when and where to perform maintenance. Any repairs are significantly less costly due to only removing targeted sections of vegetation, minimizing disruption to the building occupants.  

Case study: Passive leak detection system finds leak

Installing a leak detection system on a green roof begins with architectural drawings. SMT was contracted to install a leak detection system on a mid-rise building in downtown Vancouver featuring an extensive green roof plaza deck.  

Above: Architectural drawings with leak detection system mapped out

Once the waterproof membrane was complete, SMT installed an extensive grid of sensors laying flat on top of the membrane. On this project, the sensors were left installed in a passive state i.e. not actively taking readings of the roof environment.  

Above: Leak detection sensors covering the roof deck, directly on the waterproof membrane (Credit: SMT)

A leak detection scan was performed using a handheld DigiScan device, pinpointing damages to the membrane so they could be repaired before the membrane is covered.  

Above: DigiScan device locates a penetration in the waterproof membrane (Credit: SMT)

The leak detection system becomes part of the roof assembly, covered with a root barrier, drainage mat, insulation and green overburden.  

Above: Green roof installed on top of an inverted roof assembly (Credit: SMT)

The green roof system was completed, with planters placed around the perimeter.  

Above: Completed Green Roof (Credit: SMT)  

When a leak was discovered by a tenant, we returned to site to activate the system and take readings of the membrane environment. Multiple readings with varying levels of rooftop saturation were taken and analyzed.

Above: Portable Leak Detection System Electronics (Credit: SMT)

Data from the leak detection system was used to generate a “heat map” of the waterproof membrane, narrowing a search area for the source of the leak.

Above: CAD drawing illustrating the likely area of the leak (Credit: SMT Analytics)

A small area of green roof was removed, allowing tenants to enjoy the majority of the roof and saving a lot of time and cost.

Above: small area of exposed membrane for leak investigation (Credit: SMT) 

The exposed membrane was scanned with a DigiScan device to pinpoint the leak.  

Above: DigiScan 360 device scans waterproof membrane, giving  a vector towards the leak source (Credit: SMT)  

A damaged pipe was located, with the system also indicating that the pipe was damaged further down on a different level - allowing for a comprehensive repair.  

Above: Damaged pipe located (Credit: SMT)

The roof was re-covered, with the leak detection system used periodically to check for the health of the membrane and the success of the repairs.  

Above: Fully Covered Green Roof (Credit: SMT)

Fully automated monitoring

The best protection for a green roof is a fully automated leak detection system. SMT have now  installed 100’s of fully automated leak detection systems active across Canada and the United States, offering near-live performance data for the waterproof membranes protecting structures with green roofs.  

On one such project, our FutureCast automated leak detection system triggered an alarm for a membrane breach. The system data highlighted a small area of the green roof for removal so that the breach could be found.  

In this instance, the membrane breach had been caused during the installation of the green roof, specifically landscaping stone placed as a walkway and barrier around the perimeter of the extensive green roof. Stones from this barrier were kicked underneath the drainage mat, allowing the full weight of the overburden to press the stone into the waterproof membrane.  

This kind of damage has been seen on multiple sites and is especially pronounced where new details such as lampposts, electrical outlets or benches have been added to the roof.  

A green roof is installed with the mindset of longevity and resilience, yet at its foundation is a waterproof membrane at risk from all the daily activities of a construction site, with damages occurring that may not be obvious until well after construction is complete. Taking great care during installation of green roof elements is a good way to reduce the occurrences of these damages, but a fully automated monitoring system that lasts as long as the roof is the best long-term solution to protecting the roof.

Original article and photo source: SMT Research

By SMT Research.

Understand the risks of water exposure in mass timber construction and effective prevention strategies.

As time goes on, mass timber, particularly the use of cross-laminated timber (CLT), is used more and more in construction. Understandably so, as it's a fantastic sustainable and cost effective alternative to traditional building materials like concrete and steel. SMT often gets questions about moisture in mass timber, so we took the time to talk about our view for preventing moisture damage in mass timber roofs.

While using a new material can be ground breaking, as with any construction material, it's important to understand the potential risks associated with mass timber, particularly when it comes into contact with water. Water is a critical factor in the life cycle of wood, as it can both facilitate and impede the growth and decay processes. When wood is exposed to water for long periods of time, it can absorb moisture and become saturated, leading to potential issues that will compromise the structural integrity of the building.

One of the main risks associated with mass timber construction remaining wet for extended lengths of time is dimensional instability. When wood is exposed to water, it can swell and expand, leading to potential issues such as warping and splitting. This can affect the structural integrity of the building and potentially compromise its safety. Additionally, if the wood is not allowed to dry properly, it may shrink and contract over time, leading to potential issues such as cracking and buckling.

There is also the potential for rot and decay that must be considered when working with mass timber. When wood is exposed to water and other environmental factors, it can become a breeding ground for fungi and other microorganisms that break down the wood fibers. This can compromise the strength and durability of the building, potentially leading to costly repairs and even structural failure.

Mold growth is another potential issue associated with mass timber construction remaining wet for long periods of time. Mold thrives in damp, humid environments, and can lead to potential health issues such as respiratory problems and allergies. Mold growth can also compromise the structural integrity of the building by breaking down the wood fibers and weakening the building components.

If we were to illustrate mass timber and what happens when it gets wet, we'll use what happens to wet clothes left in a pile as an example.

Both materials can suffer from mold growth when exposed to water for extended periods of time. Wet clothes left in a pile on the floor can take a long time to dry out, as the moisture is trapped between the layers of fabric, and there is little airflow to facilitate drying. This is similar to wet CLT, which can also trap moisture within the layers of the panel and prevent proper drying.

To mitigate the risks associated with mass timber construction remaining wet for long periods of time, it's important to follow proper construction and maintenance practices, which includes monitoring the building for moisture using sensor technology. During the construction process, it's crucial to protect the CLT panels from moisture and ensure that they are properly sealed and ventilated. This may involve using leak detection tools like Digiscan to inspect the waterproof membranes, installing drainage systems, and using proper flashing and sealing techniques to prevent water infiltration.

After the building is completed, it's highly important to regularly inspect the building components for
signs of moisture damage. This can be difficult to do without compromising the design of the building, which is why SMT recommends installing FutureCast and point moisture monitoring sensors to monitor for any signs of damage that should be addressed immediately. Should a problem arise, the compiled data from the sensors will be sent directly to the building owner or manager, giving them time to make repairs before the damage becomes too great. By leaving sensors in the mass timber, we can monitor the wood for signs of damage for the entire lifetime of the building.

Although mass timber construction has numerous advantages, it's crucial to comprehend the possible hazards that could arise from prolonged exposure to water. To guarantee the building's long-term durability and safety, appropriate construction practices and monitoring the wood for moisture can be implemented to mitigate these risks.

If you would like to learn more about moisture in mass timber, or if you have a mass timber project
coming down the pipeline, we host a lunch and learn session surrounding this topic.

Contact us here, to book yours today!

From community spaces to revenue generators, how SMT's electronic leak detection system can keep your roof and assets safe.

By SMT Research

Roofs in the modern age do more than simply protect your building and assets below it. We’re seeing new buildings pop up everywhere that have their roofs serve more than one purpose, like city parks sitting on top of the roof of retail space, solar panels being installed to power the entire block, and pools being installed on top of luxury hotels.

Roofs serve as spaces for community building, reconnecting with nature, and sometimes, pose as an opportunity to generate revenue. One example is NYC’s Javits Convention Center new expansion, which included installing a rooftop farm and orchard, which will supply produce to the convention center’s kitchens. Another example is the Oakridge Redevelopment in Vancouver, which has extensive park space overtop of retail stores that is large enough to double as a concert venue and can accommodate vendors for a future market.

Since roofs have even more value now than ever before, it's that much more important to protect them and these assets. If any of the previously mentioned roofs started leaking, they would be extremely costly to replace and would negatively affect the community that relies on those other added benefits. SMT wants to stop leaks from damaging the building, and we achieve this by monitoring the roof for moisture and leaks. We want to make sure we know about moisture changes in the assembly before they become an active leak, and an active problem.

FutureCast is SMT's leading electronic leak detection system, a network of sensors that are permanently installed in a roof assembly, which throughout the lifetime of the building will look for changes in moisture and defects in the membrane that will cause a leak. FutureCast can be passive or active monitoring.

When FutureCast is actively monitoring, electronics are installed to track moisture and leak locations continuously around the clock. An active system will take moisture readings on custom intervals and send the data to a cloud server that can be viewed at any time, giving the owner a detailed baseline of what is normal for their roof. If a leak event occurs, or if there is a change in moisture levels outside of the baseline, a notification will be sent to the building owner’s email as soon as possible. Having FutureCast actively monitoring greatly benefits high value structures that cannot afford any downtime for repairs, like a national data center that houses crucial infrastructure. Active monitoring is also useful for if there is extreme risk involved with water damaging high value assets below the roof, like water dripping down into an operating room.

To suit every client’s needs, FutureCast can also passively monitor a roof. When FutureCast is passively monitoring, sensors are installed and remain dormant until a FutureCast Technician visits the site with electronics on a predetermined schedule to take readings. After an adequate amount of readings have been taken, the SMT Technician will compile a roof health report to be given to the building owner or manager. Passive monitoring greatly benefits clients who wish to preplan maintenance or wish to satisfy warranty requirements.

Modern-day roofs are much more than just a protective layer for buildings and assets. They have become spaces for community building, generating revenue, and connecting with nature. By using FutureCast, building owners can be assured that their roof is being monitored and any issues can be detected and addressed before they cause any harm to the building or community. Reach out to SMT today, so we can protect your building for years to come!

By SMT Research.

Don’t let other people damage your roof and your profitability! 

Benjamin Franklin once said, “By failing to plan, you are preparing to fail.” Creating a plan for building a new project is common, but it’s less common to create a plan for the immediate future of a new building in case of a roof leak. No one wants to think about the worst happening; a brand new roof needing to be repaired prematurely, or even worse, assets below needing to be replaced from water damage due to a leaking roof.

Unfortunately though, if the roof fails within a short amount of time after being built, the cost and planning that comes with making those repairs or replacement can be a nightmare. Not only is it a large capital expense to replace a building's roof, but in many cases it can also harm a roofer’s reputation long term by having this negative association even if it is not warranted. 

There are strategies available to mitigate this risk, but contractors often overlook them and think they’re unnecessary. However, SMT has found this outlook to be shortsighted, and the effort of protecting a building's roof far outweighs the potential replacement and repair costs. We believe that with the right plan in place, SMT can help mitigate the risk.  

Generally speaking roofers do great work, but then we have to ask, why do so many roofs have membrane breaches during construction? SMT Research has found through quality assurance scans that it is extremely common to find hundreds of damages and defects in membranes during construction before the construction project has been completed. If the membrane damage is left there, it can turn into a leak right away or later on in the building’s lifetime. Often membrane damage isn’t caused by the roofer, it comes from other factors like the roof being exposed to the elements for too long before being completed, or other tradespeople using the roof as workspace and lacking necessary education about protection of roof membranes.  

A building is constructed in stages, and during that sequencing the roof membrane is often installed to enable interior work to commence, and the membrane left exposed as a work surface in order for other work to be completed on the building.  

The roof is at risk for damage from other on-site workers like driving nails or screws through the membrane for framework support and accidental damage in areas such as using the new membrane as storage for staging materials and work surfaces.

Preventing the damage can seem impossible, especially on large projects that take years to complete and have hundreds of contractors working on at any given time. While it may seem impossible to prevent the damage from occurring, it is much more possible to find and repair the membrane breach before permanent damage to roof decks below occurs.

SMT has the solution: Digiscan — a point-in-time membrane scanning tool which detects damage or defects in the membrane. Digiscan is a non-destructive method of scanning, unlike other traditional methods of leak detection. While construction is ongoing, SMT uses Digiscan to scan the roof membrane to look for penetrations that will later cause a leak.

With Digiscan, we can scan everywhere within our adjustable guard circuit, which allows us to scan large areas quickly and efficiently. Our technology and metal detector style shape makes Digiscan lightweight and portable, making it possible to scan tricky architectural details like water features, landscaped environments, with or without even terrain. Digiscan is able to test vertical and horizontal spaces with ease, no conductive medium needed.  

SMT provides reports when we scan with Digiscan, complete with photos of all known penetrations. Having this information from the report will allow the roofer to go back and make repairs before finishing the roof, which will make the roof way less at risk for premature leaks. This documentation and method of quality assurance also protects the reputation of the roofer, if scanning is done immediately after membrane installation, the roofer can show other parties that it was installed correctly.  

Having a moisture management plan is the best way to maximize the useful life of your roof while at the same time minimizing its recurring costs. Specifically, the Digiscan gives your roof the best start to its life possible by ensuring quality installation and catching any potential defects. SMT wants to protect your building and your reputation, contact us today so we can help!  

Learn more about SMT Research in their RoofersCoffeeShop® directory or visit www.smtresearch.ca.