Improper Solar Installation Causes Big Problems
We’re on different roofs everyday. Sometimes people call us out to make repairs but often we are removing old roof systems and replacing them completely, especially when they’re worn out and old. It makes sense to do a complete replacement of a roof if the existing one is already aged beyond it’s intended lifespan.
In many cases, as well, we have to fix damage caused by other contractors. It’s not uncommon for HVAC contractors to work on top of roofs. Not all HVAC contractors are oversized and overweight, but we generally think of them as big folks fumbling around in an unwieldy and cumbersome way. A light and more accurate touch is better in working on a rooftop. We often clean up debris and make repairs after these other contractors have left their scrap materials, trash, and damage behind.
We were working on a job recently and we picked up over 30 screws brought by the HVAC contractor for connecting ductwork to a rooftop unit. They left an entire handful of screws strewn about around the rooftop near the RTU. The screws are dangerous to the roof system because as people walk around, if they’re not cognizant and careful, they will step on top of the screws and push the sharp points into the roof membrane.
We don’t want to be neurotic, but it’s natural for roof contractors, if they care about their work, to worry about the damage caused by other contractors who don’t seem to have any care at all. Here, in the picture below, we show what looks like an otherwise proper installation of a PV solar system. These solar systems are used throughout the city here in Washington, DC. The solar panels are mounted on top of an aluminum purlin system which stretches from parapet to parapet at the sides of the building.
It’s good to install the solar panels on a purlin system like this because it’s better than attaching directly to the field of the membrane at the lower area. This installation is definitely not correct though. One of the secondary problems, that we noticed right away, is that they’ve left no space for servicing the roof membrane. If they had built the panels up and additional 16 to 20 in it would be a lot easier to work underneath them in the future. It’s necessary to have access to the main field of the rooftop because all roofs need to be accessed for typical routine upkeep and maintenance.
The biggest problem of all though, here, is that they bolted their purlins down right through a 1×4 PVC board and through the top of the roof membrane. There is no coping installed on top of this parapet and the only sealant that they have used is between the PVC board and the modified bitumen roof membrane.
They have done nothing to seal the upper area and there are areas where water can run down around the base of the mounting clip and flow under the channels set into the base of the mounting clip, down through or around the shaft of the bolt, and through the hole in the PVC board.
From there, any typical cracking in the sealant from typical expansion and contraction movement, will lead to a direct leak into the building.
The building code here in DC requires that roof penetrations, parapet copings, and terminations must be flashed using approved materials and methods which are integrated directly into the modified bitumen membrane system.Some examples of approved methods are pitch pockets, liquid-applied flashing membranes, or boots. Here, a proper seal and flashing of those types has been omitted. We specifically show one mounting point up close, but there are numerous equal mounting points of the same type of hardware that have been installed throughout the roof system now. All of these penetrations and mounting points are problematic.
The building code requires an abnormal type of installation like this to have engineered solar flashing mounts approved for modified bitumen roof systems used to properly seal. They also require aluminum coping to be installed first. That coping installation wouldn’t be the responsibility of the solar panel installation company, but the solar panel installation company should have told the client or building owner to make sure that’s installed by a roofing contractor first.
Leaks, caused by solar panels, are prolific throughout Washington DC. In some specific cases of those repairs, one of the big name local solar contractors had presented the engineer drawings they used to get approval from Washington DC. They claimed that the city had approved their methodologies. In the whole set of approved documents though, there were no specific details of this sealing approach which omits a proper approved method of sealing.
Approval of a set of documents which omits the specifics is not a form of approval of an undetailed specific. They were basically trying to twist the reality into an invented scenario which would favor their lack and omission of correct sealing. As we mentioned, we see these problems again and again. We highly recommend building owners and vet their solar contractors carefully and even talk to a professional roofing contractor about the mounting methods before the solar panels are installed.
We provide this information here on our blog, and our website, to help our customers and future clients, and we recommend every building owner in DC who values the longevity of their roof (and their investments) and building use a contractor who values the simple and important principles of proper roof construction like Dupont Roofing DC.
Our company specializes in flat roofing here in Washington DC and we’re happy to help building owners of almost all types. Learn more about our company and the proper techniques of working with roofing on historic buildings in Washington DC here on our blog at DupontRoofingDC.com, and you can call us at (202) 840-8698 and email us at dupontroofingdc@gmail.com. We are happy to help and at least talk through options.
