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Common Challenges with Rooftop Retrofit Projects (and What to Do About Them)

Posted by Art Valentz on June 29, 2018

While 15 years might seem like a long time, building owners know that this average life expectancy for roofing materials and RTUs can fly by quickly.  rooftop-retrofit-challenges

That’s especially true when your traditional built-up roof starts showing signs of water damage. Suddenly you’re left with a choice—maintain the rip-and-replace cycle or make an investment in rooftop retrofit projects.

More than ever, building owners are taking the retrofit path to unlock the benefits of long-lasting, low-maintenance roofing.

However, rooftop retrofit projects aren’t without their challenges. Whether you’re looking to fully retrofit the rooftop or retrofit individual rooftop units (RTUs), here are some potential challenges to keep in mind.

 

3 Considerations for Full Rooftop Retrofit Projects

 

There’s nothing simple about fully retrofitting your commercial rooftop. The most important thing to remember is that every project is unique. Your decisions will depend on building size, the secondary structure, equipment on the roof, local codes, and more.

However, there are challenges common to just about every full rooftop retrofit project. With the right planning, you can overcome the following three.

 

1. Determining the Existing Structure’s Load Capacity

If you’re retrofitting the roof with metal (an increasingly popular option), you won’t face many challenges with load capacity. It’s a relatively lightweight option.

But if you’re installing a green roof, you’ll need to conduct comprehensive testing for load-bearing capacity because of the additional weight on the roof structure. Buildings with high load capacities can handle intensive green roofs with large plants and complex landscapes. However, most buildings would need structural upgrades to support such weight.

For most roof structures, an extensive approach with small plants and simple landscapes is more cost effective because it doesn’t require any upgrades. When you factor in the ability to replace PMRA stone ballasts with green roofs, you gain additional flexibility in load-bearing capacity.

Any rooftop retrofit project will require load testing—just remember that a green roof creates an additional layer of complexity.

 

2. Choosing the Right Roofing System Configuration

Many rooftop retrofit projects will follow one of two configurations—compact, conventional, or protected membrane roofing assembly (PMRA).

When you’re taking the compact conventional approach, pay close attention to the strength of your thermal insulation. You’re installing the new system on top of the membrane (which is on top of the insulation). If the insulation is worn out, you risk damaging the roof and distributing weight unevenly. However, you can use a cover board across the roof to mitigate the challenge.

The PMRA option often requires more effort and expertise. Because PMRA retrofits are installed with thermal insulation on top of the membrane, you have to be careful that roots don’t hinder waterproofing. If you don’t have root resistance, you’ll need to rip out insulation and install a barrier in between the system and the membrane.

With PMRA retrofits, you’ll need to prepare for moisture buildup by facilitating drainage.

 

3. Integrity Testing the Roof Membrane

Membrane condition is a critical component of successful rooftop retrofit projects. Having to go back and repair the membrane after the project results in costs that most building owners can’t accept.

Before diving into the project, you need assurance that the membrane will remain waterproof. That’s why there are multiple testing methods for contractors to take advantage of—spray testing, flood testing, capacitance testing, nuclear metering, and infrared thermal imaging.

One key factor in maintaining the waterproof integrity of the roof is minimizing the use of penetrating support equipment. For example, penetrating pipe supports (as opposed to non-penetrating options) weaken the membrane and let moisture set in. Non-penetrating roof supports extend the life of your roof while also simplifying retrofit projects thanks to their flexibility. Your integrity testing should include checks for penetrations and inform a retrofitting plan that avoids more.

With the right partner, you can be sure that the right tests are conducted to ensure successful integrity testing.

 

Additional Considerations for Rooftop Equipment Retrofitting

Many of the challenges you face during full rooftop retrofit projects also apply to smaller-scale RTU retrofitting. You still have to load test, maintain membrane integrity, factor in the system configuration, etc.

However, there are unique challenges for RTU retrofit projects, too. Mainly, the implications of replacing on an as-needed basis. When you don’t have the right replacement/retrofitting plan in place, you risk paying significantly more for emergency upgrades when equipment breaks.

The challenge is identifying which RTUs are candidates for retrofitting. Most units have a lifespan of 15-20 years—but you know there’s always the possibility that they fail earlier or last longer. Inefficient RTUs can cost you upwards of $4,000, but replacing them outright can offset the benefits of increased energy efficiency.

Rather than waiting for some sign that RTUs are inefficient or pushing them to failure, eliminate the problem by adopting a standardized retrofitting plan. RTUs that are considered efficient today lose that standing when they’re about 10 years old. Use that as a benchmark for when you should install advanced control units.

The key to any rooftop retrofit project is to make it completely customized for the building’s unique needs. That means working with a partner that can navigate these challenges (and others) so you don’t have to think of them.

Contact us today if you want to learn how we can simplify your rooftop retrofit projects.

Topics: Roof Safety, Roof Architecture, Roofing Management, Roofing Maintenance

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