Load shape: daytime, but lighter than the roof suggests
A conventional warehouse with LED lighting and limited conditioning uses far less electricity per square foot than an office or store. The roof can often hold more solar than the building will ever use, so the size of the system is usually set by the utility’s net-metering cap and your actual consumption, not by roof area.
Cold storage and refrigerated distribution are the exception. Compressors running around the clock create a large, steady load and meaningful demand charges, and those buildings can often put most of the roof to work. If you run forklifts on lithium or lead-acid chargers, that charging schedule matters too — overnight charging falls outside solar hours.
Flat membrane roofs, ballast and structural limits
Most warehouse roofs are TPO, EPDM or modified bitumen over a steel deck, and most commercial flat-roof arrays use ballasted racking — concrete blocks that hold the array down by weight instead of penetrating the membrane. Ballast adds dead load, and older tilt-up and pre-engineered metal buildings were not always designed with extra capacity. A structural engineer’s review is a normal step, and it can change the layout or rule out part of the roof.
Colorado adds its own design loads: snow drift against parapets and rooftop units, high wind on the plains and Front Range, and hail. We lay out arrays to keep drift zones and roof drains clear, and we choose modules rated to the IEC hail test, while being honest that no panel is hail-proof in a severe storm.
If the membrane has fewer than about ten years left, re-roof first or at the same time. Pulling a commercial array off to replace a roof later is expensive, and it is work we do not do. We handle roofing and solar together, which keeps one crew accountable for the membrane under the array.
NNN leases: who pays the bill decides who benefits
In a triple-net lease the tenant usually pays the electric bill while the landlord owns the roof. If the landlord pays for solar, the tenant’s bill drops and the landlord recovers nothing unless the lease or a separate agreement passes some value back. This split incentive stalls more warehouse solar projects than engineering does.
Common workarounds include the landlord owning the system and billing the tenant for the power under a lease amendment, the tenant owning the system with a roof license, or a third party owning it under a PPA. Each has legal and tax consequences, so bring your attorney and CPA into the structure before anyone signs.
Federal tax position, as of September 2026
For a taxable owner, a solar array generally needs to be placed in service by December 31, 2027 to qualify for the §48E investment credit, because the July 4, 2026 begin-construction window has closed for new projects. Storage keeps §48E eligibility much longer. Foreign-entity-of-concern sourcing rules now apply to projects starting construction after 2025, which affects equipment choice.
100% bonus depreciation was restored in 2025. How it applies to a specific array, and how it interacts with the credit, is a question for your CPA — we give you equipment and cost detail they can work from, not tax advice.
FAQ
Questions we hear
Can I put solar on my whole warehouse roof and sell the extra power?
Usually not. Colorado’s net-metering statute caps a system at up to 200% of expected annual consumption for covered retail utilities, and some utility materials cite a tighter limit, so confirm with yours. A lightly loaded warehouse often hits that cap long before the roof is full.
Will ballasted racking void my roof warranty?
It can, if the manufacturer isn’t involved. Most membrane warranties require the roofer or manufacturer to approve penetrations, slip sheets and walkway pads. We ask for your warranty documents early and coordinate with the manufacturer before installation.
I’m a tenant on a triple-net lease. Can I still go solar?
Possibly, with the landlord’s written consent and a roof license or lease amendment that covers access, insurance, removal at lease end and roof repairs. The length of your remaining term matters: a system you have to abandon in four years rarely makes sense.
Does cold storage change the math?
Yes, usually for the better. Refrigeration runs through the sunny afternoon when solar peaks, so more of the output offsets purchased power. Storage may also help with demand charges, depending on how your peak forms.
How long does a warehouse project take?
The engineering and utility interconnection review typically take longer than installation. Larger systems can trigger additional utility study, so plan on months rather than weeks and verify the current timeline with your utility.