Longmont requires a full tear-off. Roofing over your existing shingles is prohibited, and a residential roof may finish with only one layer — so if your roof already carries more than one, every layer comes off. The City of Longmont moved to the 2024 International Codes on July 1, 2026, and writes some of the most specific roofing rules on the Front Range. Below is what actually applies to a reroof in Longmont, with the city’s own sources against each rule.
Do I need a permit to reroof in Longmont?
Yes. The city’s roofing guidance is one sentence long on this point: “A permit is required to reroof your house.” The only carve-out is a genuinely small repair — replacing less than 10×10 (100 square feet) needs no permit.
That threshold cuts both ways, and the second edge is the one that catches people out.
The “one square rule”: repairs over 100 square feet mean a whole new roof
Since 2012 Longmont has enforced what it calls the 1 square rule, under local amendment 16.06.300, section R908.1. In the city’s words: “If more than 100 square feet of roofing requires repair or replacement, then the entire roof must be replaced not just the affected roof area or plane.”
So in Longmont there is no such thing as re-shingling one slope after a hailstorm. Either the damage is under a single square and it is a repair, or the whole roof is replaced. It is worth knowing that before an adjuster writes a scope for one elevation.
Can I roof over my existing shingles in Longmont?
No. “Over-lay is not allowed over existing roof,” and “residential roofs are allowed to have only 1 layer of shingles.” Where a home already carries multiple layers, all of them must be removed.
This is a real difference from the towns next door, and it is the kind of thing that makes a quote from an out-of-area crew go wrong:
- Longmont — one layer only, overlay prohibited.
- Windsor — up to two layers permitted on completion.
- Denver — tear-off required only once two or more layers already exist.
What materials and installation does Longmont require?
| Requirement | What Longmont requires |
|---|---|
| Wind rating | 110 mph sustained-wind manufacturer’s warranty. In practice this rules out ordinary 3-tab shingles — the city notes that “nearly all manufacturer’s 3-Tab shingles will not meet this code.” The stated exception is detached non-habitable structures. |
| Ice and water shield | Required. Longmont does not publish a coverage distance — it says manufacturer’s instructions and code both apply, and where they conflict the more restrictive governs. Be sceptical of any contractor who quotes you a specific Longmont inch figure; the city does not publish one. |
| Drip edge | Required at both eaves and rakes. |
| Underlayment | Minimum 15 lb. asphalt-saturated felt over a dry deck. One layer at slopes of 4:12 and steeper; a double layer from 2:12 to 4:12; below 2:12 contact the Building Department — an approved low-slope product is required and shingles are cosmetic only. |
| Fasteners | Must penetrate a minimum of 3/4 inch into the decking, driven perpendicular to the roof and flush — neither over- nor under-driven. Properly adjusted nail guns are allowed. |
| Roof deck | Must provide a rigid surface. Warped, cracked or delaminated boards and sheathing between supports get repaired or replaced. |
What inspections does Longmont require?
For a standard residential reroof, a final inspection only. The city is explicit: “ladders and mid-roof inspections are not required unless flat roof.” Heavier assemblies change that — tile or metal over 7.5 psf, and commercial built-up roofs, do get a mid-roof or ladder inspection.
The permit holder books it, through the Accela Citizen Access portal or on (303) 651-8332. Requests in by 4:00 p.m. are served the next business day.
Does Longmont license roofing contractors?
Yes, and this is worth checking before you sign anything. Longmont requires a Class D-2 contractor license — “roof covering and waterproofing”. There is no exam. A Class D license costs $75, plus a one-time $25 sales and use tax license for new contractors, and annual renewal requires proof of insurance.
Nine miles up the road, the Town of Windsor states in its own words that “there is NO contractor license required for contractors performing work within the Town.” Unincorporated Larimer County and the City and County of Denver both license roofers; Windsor licenses nobody. If you are collecting quotes across the northern Front Range, the same crew can be licensed in one jurisdiction and entirely unregulated in the next.
A homeowner may pull their own permit and do their own roof — but only on their primary residence, and only if they do the work themselves. Subcontract any part of it and that subcontractor must hold a Longmont license, while the homeowner still carries responsibility for the inspections and sign-offs.
What does a Longmont roofing permit cost?
There is no flat roofing fee. The permit fee comes off a valuation-based sliding scale in the city’s FY2026 fee manual, calculated from the project’s valuation:
| Total valuation | Permit fee |
|---|---|
| $1 – $500 | $27 |
| $501 – $2,000 | $27 + $3.50 per $100 over $500 |
| $2,001 – $25,000 | $79.50 + $16.10 per $1,000 over $2,000 |
| $25,001 – $50,000 | $449.80 + $11.61 per $1,000 over $25,000 |
| $50,001 – $100,000 | $740.05 + $8.05 per $1,000 over $50,000 |
On top of the permit fee: a residential plan review fee of 50% of the building permit fee, and sales and use tax at 4.865% combined city and county, applied to 50% of the project valuation. Fee manuals are revised annually — the figures above are FY2026.
The one square rule and your insurance claim
This is where Longmont’s code and your policy can collide, and it is worth understanding before a scope gets agreed.
After a hailstorm, an adjuster who finds damage on one elevation may write a scope to replace that slope only. That is ordinary practice, and in most towns it is also perfectly legal. In Longmont it is not. Once more than 100 square feet needs replacing, the city requires the entire roof — so a one-slope scope cannot actually be built to code.
That gap is a supplement, not an argument. Longmont’s rule is published, it is a local amendment with a section number (16.06.300, R908.1), and carriers routinely pay code-required work when it is documented properly. What loses homeowners money is nobody raising it before the scope is settled. We put the code citation in front of the adjuster while they are still writing, which is the only point at which it is easy. Our roof insurance claims process covers how that documentation works.
What to expect on a Longmont reroof
- Inspection and a one-square assessment. Before anything else, we measure how much of the roof is actually affected. Under or over 100 square feet is the question that decides whether Longmont treats your job as a repair or a full replacement, so it gets answered first and in writing.
- Material specification. The 110 mph sustained-wind warranty rules out ordinary 3-tab shingles, so the shingle gets chosen against that requirement rather than against a price sheet. Ice and water shield and drip edge at eaves and rakes are specified at the same time.
- Permit. We pull it. A contractor who asks you to pull your own permit is usually avoiding the building department’s scrutiny — and in Longmont they would also need a Class D-2 licence to be doing the work at all.
- Full tear-off and installation. Every existing layer comes off; there is no overlay option here. Decking gets inspected as it is exposed, and warped or delaminated sheathing is replaced before anything goes back on.
- Final inspection. Booked with the city by 4:00 p.m. for the next business day. On a standard residential reroof this is the only inspection Longmont requires — there is no mid-roof hold to schedule around.
One more Longmont rule worth knowing: attic ventilation
Longmont publishes an actual ventilation calculation, which most jurisdictions leave to the code book. The city’s formula is the attic footprint divided by 300, divided by 2, multiplied by 144, divided by the square inches of each ventilator — giving the number of vents required. It matters more than it sounds: under-ventilated attics are the root cause of most ice damming, and a reroof is the one moment when it is cheap to fix.
Longmont at a glance
| Question | Longmont’s answer |
|---|---|
| Permit required? | Yes, above 100 sq ft |
| Code edition | 2024 International Codes, effective July 1, 2026 |
| Overlay allowed? | No — one layer only |
| Repair vs replace threshold | Over 100 sq ft triggers a full replacement |
| Ice and water shield | Required (no published extent) |
| Drip edge | Required at eaves and rakes |
| Wind rating | 110 mph sustained-wind warranty |
| Inspections | Final only for standard residential |
| Contractor license | Required — Class D-2 |
Where these rules come from
Every rule on this page traces to a City of Longmont source:
- Roofing Guidelines for Commercial and Residential Projects — permit threshold, the one square rule, overlay prohibition, drip edge, wind rating, ice shield, inspections, homeowner permits
- Building Codes — the 2024 code adoption and its July 1, 2026 effective date
- Inspection Scheduling — how and when to book
- Contractor License Types — the Class D-2 roofing license
Longmont Building Inspection Division, Development Services Center, 385 Kimbark St, Longmont, CO 80501 · (303) 651-8332 · [email protected] · Monday–Friday, 8 a.m. to 5 p.m.
Verified against the City of Longmont’s published sources on August 14, 2026. Codes and fees change — four Front Range jurisdictions changed code edition during 2026 alone — and the city’s own roofing page still carries a stale reference to the 2021 commercial code, so confirm current requirements for your address before you sign anything. We confirm them as part of every quote. See our Colorado and Wyoming roofing code overview for the other jurisdictions we work in.
Longmont Roofing Questions, Answered
Yes. The City of Longmont requires a permit to reroof a house. The only exception is a small repair — replacing less than 10×10, or 100 square feet, needs no permit. Be aware that the same threshold works in the other direction: if more than 100 square feet needs repair or replacement, Longmont’s “one square rule” requires the entire roof to be replaced rather than the affected slope.
No. Longmont prohibits overlays outright — “over-lay is not allowed over existing roof” — and allows residential roofs only one layer of shingles. If your home already carries more than one layer, all existing layers must be removed. This differs from neighbouring jurisdictions: the Town of Windsor permits up to two layers, and Denver requires a tear-off only once two or more layers already exist.
Not for a standard residential reroof. Longmont requires a final inspection only, and states that ladders and mid-roof inspections are not required unless the roof is flat. Heavier assemblies are the exception: tile or metal roofing over 7.5 pounds per square foot, and commercial built-up roofs, do require a mid-roof or ladder inspection. The permit holder schedules the inspection through Accela Citizen Access or on (303) 651-8332, by 4:00 p.m. for next-business-day service.
Yes. Longmont requires a Class D-2 contractor license covering roof covering and waterproofing. There is no exam; the Class D license fee is $75, plus a one-time $25 sales and use tax license for new contractors, and annual renewal requires proof of insurance. A homeowner may pull their own permit and do their own roof, but only on their primary residence and only if they perform the work themselves — any subcontractor they hire must hold a Longmont license.
Longmont requires roofing with a 110 mph sustained-wind manufacturer’s warranty. In practice this rules out ordinary 3-tab shingles: the city notes that nearly all manufacturers’ 3-tab shingles will not meet the code. The stated exception is detached, non-habitable structures. Longmont specifies the 110 mph figure rather than an ASTM D7158 wind class.
The City of Longmont adopted the 2024 International Codes effective July 1, 2026, alongside the 2024 Metro Cohort Model Code for energy and the 2025 Colorado Wildfire Resiliency Code. Note that Longmont’s own roofing-guidelines page still refers in places to the 2021 International Building Code for commercial work — that reference has not been refreshed since the 2024 rollout, and the 2024 adoption is the current one.