Roof Condition, Age, and Solar: When to Install, When to Re-Roof First

The single most expensive solar mistake isn't picking the wrong panel — it's installing on a roof that fails three years later. Here's how to time it.

The simple rule

The solar system has a 25–30 year life. The roof under it needs to last at least that long, or you'll be paying to remove and reinstall panels mid-stream.

Rule of thumb by roof type:

TPO / PVC (commercial multifamily): 20–25 year life. Install on roofs <8 years old.
Asphalt shingle (SFR/small multifamily): 20–25 year life. Install on roofs <10 years old.
Metal standing seam: 40+ year life. Install almost anytime if structurally sound.
Built-up bituminous: Variable. Site assessment required.

When to re-roof first

If your roof is within 5 years of needing replacement, re-roof before solar. The re-roof cost is bundled with the install, often financed through the same PPA, and you avoid the mid-life R&R penalty (~$8K–$15K per array depending on size).

Many operators (us included) will quote both bundled and unbundled options.

When to install on the existing roof

If the roof has 15+ years of remaining life and a recent inspection confirms condition, install now. Don't wait. Every year of delay is a year of foregone NOI — typically $1,000–$8,000 per property depending on size.

The middle case

Roof has 8–14 years remaining life. The right call depends on:

How aggressive your hold horizon is
Whether the operator offers an R&R reserve
Whether the financing structure (PPA vs. owned) absorbs the cost

For PPAs, the operator typically carries R&R risk. For owned, you do. Price accordingly.

How NOI handles it

Every site assessment includes a structural and roof condition review. If your roof is too old, we'll tell you. We don't install on doomed roofs because it's bad for everyone — including us.

If a re-roof is needed, we can either bundle it into the project (financed) or refer to a roofing partner for a standalone quote. Then we time the solar install to match.

The cost of getting this wrong

A 60 kW system removed and reinstalled mid-life costs $12,000–$18,000 plus the lost revenue during downtime. On a 12-unit property, that's 1–2 years of solar NOI evaporating. Worth getting right the first time.

Want to see what your roof could earn? Estimate your NOI lift or talk to our team.