Boulder Solar-Ready Roof Replacement Guide

If you plan to add solar within the next several years, the roof under the panels should outlast them. Removing and reinstalling an array to replace a worn roof adds cost and risk. This guide covers what the City of Boulder's energy code actually requires, how roofing materials compare as a base for racking, and what to know about Xcel Energy's solar program before you schedule a reroof.

What the City's solar-ready rules cover

A common assumption is that any Boulder reroof must be made "solar ready." The City's energy code pages point to a narrower scope. The 2024 City of Boulder Energy Conservation Code (CoBECC) took effect December 1, 2024 (City of Boulder, 2024 Energy Code FAQ). The City's code update summary says it maintains "requirements that make buildings ready for solar technology as outlined in the 2020 code," and requires projects to maximize roof space for renewables when meeting new-construction performance targets (City of Boulder, 2024 Energy Conservation Code Update).

For existing homes, the City groups work into alteration levels (City of Boulder, Energy Conservation Code). A Level 1 alteration is the removal and replacement or covering of existing materials with new materials that serve the same purpose, which describes a typical like-for-like reroof. Level 3 and Level 3+ alterations cover work exceeding 50% of the building area, with added electrification requirements. Confirm which category your project falls into with the City when you apply, using the residential building permit guide; a reroof also needs the inspections in the roof inspection guide.

Standing seam metal vs Class A asphalt as a solar base

Standing seam metal lets racking clamp onto the raised seams without drilling through the roofing, which removes many roof penetrations. Metal roofs also typically last much longer than asphalt; Angi cites 30 to 100 years for metal versus 15 to 30 years for asphalt shingles (Angi). That longer life is the main reason metal is often paired with solar.

Class A asphalt shingles cost less upfront and are what most solar installers work with every day. Racking attaches with flashed mounts that penetrate the shingles and attach to the rafters or decking. The concern is lifespan: if the shingles wear out before the panels, the array has to come off for the reroof.

For Boulder specifically, also consider hail. If you choose asphalt, an impact-rated (Class 4) product may reduce the chance of a hail-driven reroof under the array; see our hail and Class 4 guide. Fire ratings matter too in wildland-urban interface areas; see our wildfire roofing code guide.

Planning the roof around the array

• Space: Xcel's Solar*Rewards FAQ estimates roughly 120 square feet of unshaded roof space per kilowatt of solar capacity, and notes that a southern orientation is ideal but east and west roofs also work (Xcel Energy, Colorado Solar*Rewards FAQ).
• Vents and penetrations: group plumbing vents and exhaust outlets away from the best solar planes during the reroof.
• Decking and structure: replace damaged decking while the roof is open, and ask the solar designer whether a structural review is needed.
• Underlayment and flashing: plan for the mounts to be flashed into the new roof rather than sealed on top later.
• Warranties: ask both the roofer and the solar installer how mounting affects their warranties before work starts.

Questions to settle before the reroof

• How long until you expect to install solar, and will the roof material's remaining life cover the array's expected life?
• Which roof planes face south, east or west with the least shade from trees, chimneys and neighboring buildings?
• Will the HOA, if any, review panel placement or roof material changes?
• Does your roofer's workmanship warranty survive later solar mounting, and under what conditions?
• Will the solar installer use flashed mounts compatible with your new roof's manufacturer instructions?

Answering these before the old roof comes off is far cheaper than redoing flashing or moving vents after the panels are designed.

Xcel Energy's solar programs

Xcel's Colorado Solar*Rewards program pays system owners for Renewable Energy Credits in cents per kWh for the energy their system produces, and all solar customers receive net metering benefits, with excess energy banked for future months (Xcel Energy, On-site Solar). Xcel recommends not starting construction until the application has full engineering approval and all agreements are signed. The FAQ lists a $100 interconnection study fee for Level 1 systems of 10 kW or less. Incentive rates change; check Xcel's current program pages before you sign anything.

If you already have panels

Temporary removal for a roof replacement is its own line item. Angi lists temporary removal for a roof repair or replacement at $1,000 to $2,000, removal overall at $200 to $500 per panel, and roof patching after removal at $300 to $1,000 (Angi). Coordinate the solar contractor and roofer so the array goes back on promptly and with proper flashing.

Sources: Angi, roof replacement cost; Angi, solar panel removal cost. Ranges are attributed to the publisher named; they are national or regional estimates compiled by that publisher, not quotes and not prices from any provider on this site.

Local rules and code references

• City of Boulder, 2024 Energy Code FAQ: CoBECC effective Dec. 1, 2024.
• City of Boulder, 2024 Energy Conservation Code Update: solar-ready requirements maintained; maximize roof space for renewables.
• City of Boulder, Energy Conservation Code: alteration levels 1, 2, 3 and 3+.
• City of Boulder, Residential building permit guide: permit submittals.
• City of Boulder, Roof inspection guide: reroof inspections.
• Xcel Energy, On-site Solar (Colorado): Solar*Rewards REC payments; net metering; wait for approval before construction.
• Xcel Energy, Colorado Solar*Rewards new customer FAQ: about 120 sq ft per kW; $100 Level 1 study fee.

Code text, policy forms and department procedures change. Confirm current requirements with the jurisdiction, your insurer or the utility before work starts.