Roof Replacement With Solar Panels in Thornton, CO

When the roof under an existing array wears out, the modules come off, the roof is replaced, and the same array goes back on. The order matters: a solar company or electrician shuts the system down, disconnects and removes the panels and rails, and stores them; the roofer tears off and re-roofs, including new flashing at every mount location; then the solar crew re-installs and recommissions the system. Thornton's permit list says reinstalling an existing solar PV system doesn't need its own permit, though the re-roof still does. Ask whether the roofer coordinates with your solar company or whether you'll be booking both. Also ask who is responsible if a panel is damaged in storage.

If panels aren't up yet and the roof is mid-life or older, replacing it first saves paying for a detach and reset later. Put panels on a roof with only a few years left, and that extra step comes due sooner than the panels do. Compare the roof's remaining life with how long you expect to keep the panels; lifespan by material is set out on roof replacement. Doing the roof first also lets the roofer and the solar designer agree on where the array will sit, so mount locations can land on rafters and avoid valleys and vents.

A rooftop array stands on rows of lag-bolted feet, and each one is a hole in the roof. The 2024 IRC says those penetrations must be flashed and sealed to the roofing chapter's rules, and that mounting systems must be listed to UL 2703 and installed to the maker's instructions. The good version is a flashing plate that slides up under the shingle course above, with the foot fastened through it into a rafter, not a foot screwed onto the shingles with a blob of sealant. Thornton's solar submittal guide asks for cut sheets showing how the mounting feet will be flashed. Ask to see that detail before the panels go back on.

Building-integrated photovoltaic (BIPV) shingles replace part of the roof covering with solar cells, so there's no separate array or racking. The 2024 IRC requires them to be listed and labeled to UL 7103, limits them to slopes of 2 in 12 or steeper, and puts them under NFPA 70, the electrical code. Where hidden wiring under the covering creates places a firefighter shouldn't set a ladder, the code calls for reflective markings visible from the ground. Because the shingles are both roof and power system, ask how a leak or a damaged shingle gets fixed later, and by whom: the roofer, the solar installer or the manufacturer's network.