A standby generator sits outside many Ladue houses, usually on a concrete pad near the foundation, with a gas line feeding it and a transfer switch on the wall that moves the house onto generator power when the grid goes down. Its exhaust outlet, its fuel shutoff and its control wiring are all close to the walls the roofers will be working beside. When the roof comes off, that equipment can be covered in debris, nailed around, or left energized on a circuit nobody meant to leave live. None of this is a reason to delay the roof. It is a reason to put the generator on the work plan before the first shingle lifts.
Where the generator sits against the house
Most standby units are set at grade, but the pad is often within a few feet of the wall, and the unit is often tucked into a corner where the eave comes down low. The roofer will set a dumpster, stage shingle bundles and run a magnet along the drip line. Each of those can land on the enclosure, in the air intake or on the exhaust hood. Granules and nail heads that get pulled into a generator intake can cause trouble at the next outage, and a unit dented by a falling bundle may not run at all. Walk the house with a phone before the crew arrives and photograph the unit from three sides: the pad, the wall it sits against, and the eave above it.
Also check whether the exhaust outlet or any service vent runs up the wall close to the eave. Manufacturers set minimum clearances from openings and walls, and the installer should have recorded them on paper. Even a correctly placed outlet can sit within reach of a ladder, a staging plank or a pry bar. If the outlet is in the path of the work, the crew needs to know before the job starts, not on the third day.
What the tear-off can damage
Three things go wrong often. The first is the fuel line. A gas line that runs along the foundation near the roof work can be struck by a dropped tool, a pry bar or a stack of shingles sliding off a ladder. The second is the transfer switch and its conduit, which is often mounted on the wall under the eave, right where flashing and drip edge work happens. The third is the generator's control cable, which runs from the unit to the switch and may be routed up the same wall space the roofer will cut into when the starter course goes in. None of these is certain on every job. All of them are cheap to avoid once the crew knows they are there.
There is also the question of what happens if the power fails during the job. A reroof leaves the attic open, the decking exposed and the house without its usual weather protection for a day or more. If the generator is set to start on an outage, it will do so while the crew is on the roof. The crew should know whether the unit will run, where its noise and exhaust will go, and who will be on hand to deal with it.
Shut it down, and get the instruction in writing
Do not leave the decision to the roofer's judgment alone. The generator service company, or the electrician who installed the transfer switch, should say how to put the unit into a safe state for the tear-off. That usually means turning the unit off at its control panel, setting the transfer switch to the position the installer recommends, and closing the fuel valve if the manufacturer's instructions call for it. Ask the service company to write down the steps, and ask who will turn the unit back on after the final inspection. A written note in the file is more useful than a verbal promise that someone will remember.
Ask the service company whether closing the valve at the unit is enough, or whether anything at the meter needs to change. Do not assume the answer. The roofer's job is to ask for the instruction and follow it, and the homeowner's job is to make sure the instruction exists before anyone climbs the ladder.
Permits and the generator
A roof replacement in Ladue is handled through the city's building desk, and whether the generator was permitted when it was installed is a separate question from the roof permit. If the unit or its transfer switch was added after the house was built, ask the desk or the installer whether the permit records are on file. A roofer who notices a discrepancy should tell you about it, and you should not have to discover it after the job is finished. This is not something a roofer can settle for you. It belongs to the city and to the electrician who did the work.
Write the generator into the scope
A written scope for a roof on a house with standby power should name the generator, its pad, its exhaust outlet, its transfer switch and its fuel line as items the crew will protect or work around. It should say who covers the unit during the tear-off, who shuts it down and brings it back, and what happens if the crew needs to cut or move any conduit. Keys documents the existing condition with photos and measurements and puts that written scope in the homeowner's hands before work starts. The scope is the place to say that the generator is in the work area, so nobody is surprised by it on day two.
Ask the roofer to cover the unit for the duration of the tear-off, to keep the dumpster and bundle pallet a set distance from the pad, and to keep the lift and nail gun clear of the conduit. The exact distance matters less than having one written down. Ask for it in the scope, not on a phone call.
Questions to ask before the first day
- Which walls and corners in the work area have a generator, a gas line or a transfer switch on them?
- Who will confirm in writing how the unit is shut down, and who turns it back on?
- Where will the dumpster and bundle pallet sit in relation to the pad and the air intake?
- Will the crew cut, move or re-route any conduit or the control cable, and if so, who does that work?
- Will the starter course or drip edge cross the exhaust outlet, and how will the flashing be detailed there?
- Does the city's record show a permit for the generator and transfer switch, and where is that record kept?
If you want someone to walk the yard with you before the roofers are scheduled, call Keys at (314) 220-2333. Bring the generator's model plate and the installer's name if you have them, because those two details answer many of the questions above.