Key numbers
45 verified hail storms with stones of 1.75 inches or larger reached Denver County from 1984 to 2026 in the storm records we keep; the largest measured 4.5 inches (softball size) on July 13, 2011 (NOAA NCEI).
| Hail storms by decade, 1984 to 2026 | 1980s: 1, 1990s: 4, 2000s: 12, 2010s: 17, 2020s: 11 Source: Storm library: Denver metro hail history |
|---|---|
| Largest hail | 4.5 in. (softball), July 13, 2011 Source: NOAA NCEI |
| Costliest hail storm | $2.3 billion insured losses (2017 dollars), May 8, 2017 Source: RMIIA |
| 1.49 million | Slate or synthetic slate was the main roofing material on 1.49 million U.S. homes in 2020. Source: U.S. Energy Information Administration (EIA), 2020 |
| Over 50 | NAHB's 2007 study says slate, copper and clay/concrete tile roofs have the longest life expectancy, over 50 years. Source: National Association of Home Builders / Bank of America Home Equity, 2007 |
A storm counts when the library lists Denver County among the areas it hit. Each hail size is the storm's largest report, which may have fallen in a neighboring county, and insured losses cover every area the storm hit.
Slate is right for a Denver home when you want the longest-lasting roof available and the house can carry the weight. Natural slate is quarried stone: it can outlast several asphalt roofs, but it is heavy, expensive, and needs a crew that knows slate. Synthetic slate gives a similar look at a fraction of the weight and is the usual choice when the framing was built for shingles. Before we quote either, we check the framing, because Denver designs roofs for a 35 psf ground snow load and slate adds to what the structure already carries.
Natural slate vs synthetic slate
| Natural slate | Synthetic slate | |
|---|---|---|
| Material | Quarried stone, split into tiles | Polymer or composite tiles molded to look like slate |
| Weight | Heavy. Moving from shingles usually means an engineer’s review | Light enough for most framing built for shingles |
| Life | The longest of any common roof, when the flashing is maintained | Long, set by the manufacturer’s warranty |
| Cost | The highest of the roofs we install | Less than natural slate, more than architectural shingles |
| Repairs | Individual slates can be swapped by a slate-experienced crew | Pieces replace much like shingles |
What Denver’s rules mean for slate
- Reusing slate is allowed. Denver lets existing slate, clay or concrete tile be reinstalled if it is not damaged, broken or deteriorated, and any rusted or damaged flashing must be replaced. That makes a careful repair or a flashing-only rebuild a real option on an older slate roof.
- The permit covers the structure. A full replacement needs a Denver permit, and switching to a heavier roof brings framing questions. Around the metro, Lakewood asks for an engineer’s letter for roofing of 7.5 pounds per square foot or more, and Adams County (including Henderson) requires an engineer’s approval to switch from shingles to tile.
- Fire rating in the foothills. Inside mapped wildfire areas, the Colorado Wildfire Resiliency Code requires a Class A roof covering. Natural slate is stone; for synthetic products, check the listing.
Cost and value
Slate is a long-term purchase. For numbers, read slate roof cost in Denver and will a slate roof add value to your home. If slate is out of budget, tile and designer asphalt shingles give a similar look for less, and financing can spread out the cost of an upgrade.
Talk to a Denver slate crew
We are veteran-owned, family-run since 1990, an Owens Corning Platinum Preferred contractor, and have 650+ Google reviews. Our Denver-area office is in Centennial and we reply the same business day. Call (303) 209-0152 or book a free Denver roof inspection. We will tell you honestly whether your slate needs repair or replacement.
Sources: City and County of Denver, Roofing Guide and Checklist (updated 4/11/2024); City of Lakewood, Roofing and Re-roofing handout; Adams County, Residential Roofing Requirements (July 2026); Colorado Division of Fire Prevention and Control, 2025 Colorado Wildfire Resiliency Code.
