Before a reroof, you should know your house. Our homeowner guides for Colorado Springs, Denver and the Front Range explain the background a reroof decision rests on: what roofing and siding a house of your era probably has and what older materials need care, how roofers measure a roof in squares and pitch factors, what Owens Corning requires for a proper install and a warranty, what the IBHS hail ratings add to the Class 4 label, and how roofing material prices have moved since 2000. Each guide cites the code, manufacturer or government source it rests on. This is general information; your roofer and building department make the call on your home.
Jump to: Home eras · Measurements · Products and installation · Market context · Related guides
Roofing by home era
The year a house was built predicts a lot: roof shape, original materials, whether lead paint or asbestos siding is likely, and which flashing details tend to fail. About half of Denver County’s housing units were built before 1980, compared with about a third in El Paso County, according to the Census Bureau’s 2024 American Community Survey.
| Era | Typical houses | Guide |
|---|---|---|
| Before 1940 | Bungalows, Foursquares, Tudors, Victorians | Pre-1940 homes |
| 1940s and 1950s | Minimal Traditional cottages and early ranches | Post-war ranch homes |
| 1960s and 1970s | Ranches, split-levels, bi-levels, mansards | Split-level and bi-level homes |
| 1980s to 2000s | Two-story tract homes with cross gables and hips | 1980s to 2000s two-story homes |
| 2010 and newer | Modern farmhouse and contemporary designs | 2010s and newer homes |
The roofing by home era overview compares all five side by side.
Measurements and bids
Two bids on the same house can show different roof sizes. The roof measurement guide explains squares, pitch factors, waste and why reports disagree, with a pitch table you can use to check any number on a bid. For which materials each pitch allows, see roof slope and pitch.
Products and installation
| Guide | What it covers |
|---|---|
| Owens Corning installation requirements | Nailing, starter, ice barrier, ridge and ventilation rules in Owens Corning’s own instructions |
| IBHS shingle impact ratings | How the IBHS Good and Marginal ratings differ from a UL 2218 Class 4 label |
For the products themselves, see the Owens Corning shingles we install and whether a Class 4 roof is worth it.
Market context
The roofing material price trends guide walks through federal producer price data for asphalt roofing, steel, lumber, gypsum and paint since 2000. It is context for why bids change, not a price list.
How to use these guides before a reroof
- Find your build year on your county assessor’s record, then read the matching era guide for what is likely under your shingles.
- Look from the ground and the attic using the checks in that guide. Stay off the roof.
- Ask every bidder for the same numbers: total squares, pitch of each section, waste, and the product names for shingles, starter, ridge, underlayment and ice barrier.
- Compare those numbers with the measurement and installation guides, so you can tell a real difference in scope from a different way of counting.
- Check the hail rating by product name if hail is why you are reroofing.
- Keep the paperwork: the contract, the bundle label photo, the permit and any warranty registration.
Key numbers from the guides
| Figure | What it means | Source |
|---|---|---|
| 1979 and 1990 | Median year built in Denver County and El Paso County | Census Bureau, ACS 2024 |
| 87%, 69%, 24% | Share of homes likely to have lead paint if built before 1940, 1940 to 1959, and 1960 to 1977 | EPA |
| 32 sq ft | Suspect asbestos material on a Colorado house that triggers a certified inspection before work | CDPHE |
| 2:12 and 4:12 | Lowest slope for asphalt shingles, and the slope below which double underlayment is required | 2021 IRC R905.2.2 |
| 1.118 | Pitch factor for a 6:12 roof: 1,000 sq ft of footprint becomes about 11.2 squares | Slope geometry |
| 4 | Standard nails per Owens Corning shingle; 6 over 21:12 | Owens Corning |
| 23 of 27 | Impact-resistant shingles rated Good by IBHS; the other 4 rated Marginal, none Excellent | IBHS |
| +278% | Change in the producer price index for asphalt roofing products, January 2000 to September 2026 | BLS via FRED |
Related guides elsewhere on the site
- Common roof problems and their fixes, from pipe boots to attic frost.
- Roof maintenance checklist for spring and fall.
- Hiring a roofer checklist.
Talk to a roofer who will explain the details
Integrity Roofing and Painting is veteran-owned and family-run since 1990, an Owens Corning Platinum Preferred contractor with 650+ Google reviews. We would rather you understand your roof than take our word for it. Colorado Springs area: (719) 488-2800 or a free inspection. Denver metro: (303) 209-0152 or a free Denver inspection. Austin: (512) 610-5897 or a free Austin inspection. Same-business-day reply.
Sources: U.S. Census Bureau, ACS 2024 1-year, table B25034 Year Structure Built, Denver and El Paso counties (via Census Reporter); History Colorado, Colorado's Historic Architecture and Engineering Guide; EPA, Sources of Lead; CDPHE asbestos guidance; 2021 IRC Chapter 9 (UpCodes); Owens Corning wind classifications bulletin; IBHS shingle ratings; BLS PPI WPU1361 via FRED.
