The Membrane Decides Whether You Should Mount Solar Yet
Most owners who call us about a rooftop array in Burlington have already lined up an installer and an interconnection agreement with Green Mountain Power, and they assume the roof is a non-issue. It almost never is. The first thing we want to know is how many years of watertight service the existing membrane actually has left, because that single number drives the entire project. Put a photovoltaic system on a roof with seven years of life remaining and you have quietly scheduled a brutal future job: de-energizing the array, craning down every module and rail, storing it on site, tearing off and replacing the roof, then reinstalling and re-commissioning the whole system. On a mid-size Burlington rooftop that detach-and-reset work can add tens of thousands of dollars that simple sequencing would have eliminated. So we core the assembly, run a moisture survey, and give you a straight read before anyone signs a solar contract. A young, dry roof gets prepped for panels. A roof near the end gets replaced first, with the array installed on a fresh membrane the same season.
Racking, Penetrations, and Keeping Water Out
There are two ways to anchor an array to a low-slope roof, and each one carries a different roofing consequence. Ballasted racking holds the panels down with weight, usually concrete pavers or filled trays, so nothing gets drilled through the membrane; the trade-off is a heavy added dead load and a hard dependence on slip sheets and protection pads so the rails never chew through the roof surface. Mechanically attached racking bolts down through the deck, which turns every stanchion into a roof penetration that has to be flashed like any other curb or pipe boot. That means a welded target patch or a manufacturer-approved post flashing at each foot, not a bead of caulk that fails in three winters. On the older brick mill buildings along the Pine Street corridor we usually favor attached systems, since the structure tolerates fasteners better than it tolerates a pile of added ballast. On newer distribution and flex buildings out toward Williston and the airport approach in South Burlington, ballast is often the cleaner answer because it leaves the field of the roof uncut.
Wind Uplift Coming Off Lake Champlain
A flat array is a sail, and Burlington sits in an exposed wind regime coming off Lake Champlain. The racking layout, ballast weight, and attachment spacing all have to be engineered against the actual uplift pressures for this site and this building height, with extra securement concentrated at the corners and perimeter zones where uplift always peaks. We hold the racking engineer's load numbers up against the real roof assembly so the attachment pattern the solar side wants is one the membrane and deck can genuinely accept rather than one that only looks fine on paper.
Snow Load and the Weight Question
Vermont roofs carry real ground snow loads, and panels do not shed snow the way an open roof does. Drifts pile and linger against the rail rows long after the surrounding field has cleared. Between the dead load of ballasted racking and the way an array reshapes snow accumulation, your structural engineer needs current capacity numbers before anyone orders a single piece of steel. We make sure that conversation happens during design, not after the pallets arrive on the dock.
Conduit and the Details That Leak Two Years Later
Here is what we see again and again: the leaks on a solar building are rarely under the panels. They are at the electrical penetrations the solar crew added after the fact. Conduit run flat across a membrane abrades it; conduit punched through with a generic rubber boot turns into a slow drip within a couple of seasons. We want conduit carried on raised pipe supports with protection pads underneath, and every roof penetration for wire, combiner, or disconnect flashed properly and welded into the field membrane. The rule we hold to without exception is simple: the roofer flashes anything that passes through the roof, and it happens before the electrician pulls wire, never after.
- Membrane coring, moisture survey, and remaining-life estimate before any solar contract is signed
- A clear reroof-first versus solar-now recommendation, with the future detach-and-reset cost spelled out in dollars
- Racking and ballast review checked against structural capacity and Lake Champlain wind uplift zones
- Penetration flashing and conduit supports welded and inspected by our own crew
- Membrane manufacturer warranty review and registration so coverage survives the array
Membrane Choice and Coordinating Two Warranties
For a solar roof in Burlington we typically specify a reflective white TPO or PVC membrane at 60 mil or heavier. The white surface runs cooler beneath the array, which the modules prefer, and the added thickness stands up to the maintenance foot traffic that moves between panel rows over the system's life. The piece owners overlook most often is warranty coordination. Your membrane manufacturer's material warranty and your solar installer's workmanship warranty are two separate documents, and one badly detailed penetration lets each party point the finger at the other while your ceiling stains. We bring the membrane manufacturer's field representative out to review the attachment and flashing details before installation, document every as-built penetration, and register the completed system so the roof warranty stays intact with the panels in place. Most major TPO and PVC manufacturers permit rooftop solar on a warranted roof as long as their penetration and protection requirements are met; our job is to make sure they are and to put it on paper.
How We Work Alongside Your Solar Installer
We do not sell panels, and that independence is the whole point. Our only stake is the roof, so our read on it is not bent by a solar commission. We sit down with your chosen EPC during pre-construction, walk the conduit routing, lock down each penetration detail, agree on the build sequence, and set the joint inspection both warranties depend on. If you are still weighing bids, we will read the roof-attachment scope in each proposal and tell you plainly which contractor treats the membrane as something to protect rather than something to drill through and forget. Call 802-744-0749 or email team@commercialroofingvermont.com to set up a solar-readiness review on your Burlington building.
Common Questions About Solar Roof Integration
Should we reroof before installing solar, or mount on what we have?
It comes down to remaining membrane life. With fifteen or more years left and a dry assembly, we prep and mount on the existing roof. With seven years or fewer, reroofing first almost always wins, because the cost of detaching and resetting an array during a future tear-off dwarfs the cost of replacing the roof now and installing on a fresh membrane the same season. We core the roof and run a moisture survey to give you that number before you commit a dollar.
Will the racking put holes in our roof?
Only with a mechanically attached system, and then every stanchion gets a welded or manufacturer-approved flashing that stays under the membrane warranty. Ballasted racking holds the array with weight and never penetrates the field, but it loads the structure more heavily, which is exactly why the choice is made with your structural engineer rather than left to the solar crew.
Can our Burlington roof structure carry the added weight and snow?
That is a structural-engineering question we insist on answering during design. Ballast dead load, plus the way panels trap and drift Vermont snow against the rail rows, both have to be checked against the building's capacity before any steel is ordered. We hand the array dead load and snow-drift assumptions to the engineer so the layout you build is one the deck can truly carry.
How do we keep the array from voiding the roof warranty?
By bringing the membrane manufacturer's field representative in before installation to approve the attachment and flashing details, then registering the as-built system. Most major TPO and PVC manufacturers allow rooftop solar on a warranted roof when their penetration and protection requirements are followed, and we make sure they are and document it for the file.
Do you coordinate directly with our solar contractor?
Yes. We hold a pre-construction meeting with your EPC to set the sequence: membrane installed and inspected first, our crew flashes every penetration, then the electrician pulls conduit on raised supports. We document the routing and the details and set the joint final inspection both the roofing and solar warranties rely on.