Best Practices for Ensuring Metal Roof Accessories are Properly Installed

Best practices for roofing contractors, general contractors…and even architects—from spec’d work to pre-roofing conferences.

Many metal roofs have roof penetrations for accessories installed by other trades. Unfortunately, oftentimes, these penetrations are improperly made or the accessory material is incompatible with the standing seam roof. A properly installed Galvalume standing seam roof, for instance, can be expected to last 60 years or longer. However, improper work on the roof by other trades can result in leaks and possibly a roof service life far less than 60 years. In order to achieve the best results, the roofing contractor needs to coordinate with the general contractor, the architect, and the building owner to ensure proper installation.

In most cases, it is the roofing contractor who is held responsible for all things roof! If armed with a clear checklist as he or she walks into a pre-roofing meeting with the architect, there will be a significantly greater likelihood of a well thought out and successful process. Here are some suggestions for the roofing contractor (in conjunction with the entire team) to consider.

  • A reminder to specifiers to put in the project specifications that all roof penetrations and roof accessory installation must be coordinated with the roofing contractor. Beyond the obvious issue of maximizing performance, if a manufacturer’s weathertightness warranty is specified, the roof manufacturer must preapprove any work performed on the roof by other contractors.
  • If the above is not in the project specifications, the roofing contractor should initiate the conversation during the pre-roofing  conference with the architect and the general contractor.
  • Roof curbs should ideally be supplied by the roofing contractor and they should definitely be installed by the roofing contractor. Welded aluminum curbs should be used as specified by the roofing manufacturer. See tips for installing roof curbs, here.
Best practices
Be sure to use the proper roof curb to ensure a well-installed, weathertight condition.
  • Pipe penetrations for vent pipes, heater flues, gas and electric, etc. as well as penetrations associated with lightning protection air terminals and cable management should be coordinated with the roofing contractor and with the roofing manufacturer if there is a  weathertightness warranty. Rubber roof jacks should always be used.
Best practices
The above example is a high temperature rubber roof jack. Pipe penetrations allow for a long-term performance of the roof.
  • Ensure that dissimilar materials such as copper, lead, and graphite are not used on the roof. This includes treated wood, which contains copper. Condensate from roof top AC units must be piped off the roof as it contains dissolved copper.
Best practices
This is an example of wood and HVAC condensation on a metal roof.
  • The roof must be protected from spills of any harmful chemicals or masonry products.

The above represents just an overview of some of the best practices the roofing contractor should consider when entering into a job with other trades. As the roofing contractor, anything that involves the roof will likely be seen as YOUR purview. After all, if there’s a leak, who are they going to call? That said, being proactive regarding roof accessory installation—regardless of who is doing the actual work—will serve all parties in the end. Get in front of any potential issues and ensure everyone is reading from the same playbook. For more information, contact your local sales representative.

Roof Penetrations Made by Non-roofing Contractors

In our last two posts, we have looked at the proper ways for roofing contractors to address different types of penetrations in metal roofing in order to assure that a watertight seal is achieved from the outset, as well as over the life of the roof. But what happens when another contractor, such as a plumber, electrician, or other trade needs to penetrate the roof? How is the watertightness of the roof assured then?

Warranty Control for a Metal Roof

Most metal roofing warranties are very specific about what is included or not included should a roof leak occur. Therefore, the manufacturer’s warranty should be the first thing that is checked for a particular project to determine whether a seemingly innocent bit of work on the roof has the potential for a loss of warranty coverage. Commonly, qualified roofing contractors need to do the work and it needs to be inspected, but in some cases, supervised work may be acceptable too. Either way, any penetration installed by a trade contractor other than a roofing contractor should be fully coordinated with the architect or owner’s representative, the roofing manufacturer’s representative, the general contractor, and the roofing contractor. Once reviewed, there may be several options on how to proceed.

Guided Installation

For a single or simple penetration, say for a single small mechanical or electrical line, it may be possible to simply work with the trade contractor on the location of the penetration, review in advance that the proper materials are being used, and check the quality of the work for watertightness when complete. (Note: following the guidelines in our prior post on Pipe and Flute Penetrations will provide a good checklist of things to cover.) If everything is appropriately done, then it may be possible to have the roofing manufacturer add the new penetration to the list of items covered under the warranty.

Lightning Rod
Lightning Rod Application for Metal Panels

Coordinated Installation

In some cases, numerous penetrations may be required, such as the installation of multiple lightning rods across a roof. In this case, it might be more prudent to consider a coordinated, cooperative effort to allow each trade to do what it does best and keep the warranty in effect. Instead of an electrician being responsible for the roof penetrations and for lightning rods, let him focus on the lightning protection and wiring aspects of the work. But first, bring in a roofing contractor to advise on the proper locations of the lightning rods and to be the one responsible for the watertight seal. Location advice would include things like avoiding valleys, standing seams, or other areas that are difficult to seal or flash around. The electrician could then make the needed lightning rod penetrations in the agreed-upon locations and complete his work. Following right behind, the roofing contractor could install retrofit rubber roof jacks around the lightning rods and assure that they are sealed properly. Alternatively, the roofing contractor could make the penetration and allow the electrician to install the lightning rod, while the roofing contractor installs an appropriate rubber roof jack over or around it. Either way, the two trades need to  review the process ahead of time and be sure that everyone is on board to produce the best results for everyone involved.

Bottom Line: Think Through Penetrations

roof penetrations
Standing Seam Roof Penetration

Standing seam metal roofs have become more complex in recent years, with more and varied types of roof penetrations. This simply magnifies the need for better communication between the design professional, roof manufacturer, general contractor, roofing contractor, and any of the various trades that might be working on the roof.

When everyone takes the time to plan up front and think through their own needs and the options to get there, everyone wins. The architect/owner representative can ensure that his or her clients get a roof that will perform long-term. The roof manufacturer is able to provide expertise that has been gained over a long period of time through working with similar details on roofs all over the country. The roofing contractor can leave the project knowing that the details are long-term and will mean little chance for leak callbacks. Plus, the general contractor and the building owner can quickly resolve any arguments over which trade is responsible for repairing a roof leak.

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