Roofing in Longmont, CO

Roofing in Longmont runs through a short but specific set of city rules before the first bundle of shingles goes up. The city requires a permit to reroof a house, allows only one layer of shingles, sets a wind-warranty minimum for asphalt shingles, and requires ice-barrier underlayment. Our crew builds every Longmont roof schedule around those requirements rather than treating them as paperwork to handle afterward.

When a Longmont Reroof Needs a Permit

Longmont requires a permit to reroof a house. Repairs are treated differently: replacing a small area that comes to less than 100 square feet of the total roof does not need a permit. Once the repaired or replaced area passes that 100-square-foot line, the city applies what it calls the “1 square” rule.

Under that rule, if more than 100 square feet of roofing needs repair or replacement, the entire roof must be replaced, not just the damaged plane. A homeowner may pull the reroof permit and do the work without a contractor’s license, as long as the house is their primary residence and no contractor performs the labor.

We measure the damaged area early in the estimate. That number decides whether the project is a small permit-exempt patch, a permitted partial repair, or a full reroof under the 1-square rule, and it changes the material order and schedule accordingly.

Only One Layer of Shingles, No Overlay

Longmont allows residential roofs to have only one layer of shingles. Overlaying new shingles over an existing roof is not allowed, and where an asphalt shingle roof already has multiple layers, all of the existing layers must come off before the new roof goes on.

That means our crews plan for a full tear-off on nearly every Longmont reroof, not a quicker overlay job. We check the number of existing layers during the estimate walk so the disposal, dumpster sizing, and labor schedule reflect the real scope rather than a lighter overlay assumption.

Tear-off also exposes the deck for inspection. Longmont’s guide calls for repairing or replacing any sheathing that is warped, cracked, or delaminated between supports before new underlayment goes down, so that step is part of the tear-off day, not an afterthought.

Wind Warranty and Ice-Barrier Underlayment

Per adopted code, every asphalt shingle used in Longmont must carry a manufacturer’s wind warranty of 110 mph sustained wind, and 3-tab shingles are not allowed unless they are laminated. Longmont also requires Ice & Water Shield-type ice-barrier underlayment, installed per the manufacturer’s instructions and code.

Underlayment beneath that ice barrier follows slope. Roofs sloped 4:12 or greater need one layer of minimum 15-pound felt over a dry deck; roofs between 2:12 and 4:12 need a double layer; anything under 2:12 requires contacting the Building Department directly, since an approved low-slope product is required instead of shingles.

We select shingle products with the 110 mph warranty and ice-barrier compatibility before ordering, and we check the actual roof slope against those underlayment tiers rather than assuming a single detail works across the whole roof.

Tile, Metal, and Low-Slope Roofs Add Their Own Steps

If the selected roofing material exceeds 7.5 pounds per square foot, Longmont requires an engineered analysis of the roof structure before installation, and the manufacturer’s specifications and installation instructions must be kept on site for both the installers and the building inspector. A mid-roof inspection may be required for these systems.

Low-slope roofs have their own path too. Rolled roofing is allowed on slopes as low as 1:12 when installed per the manufacturer’s instructions, with an edge and eave overhang of 3/8 to 1/2 inch, but slopes below 2:12 still require a direct conversation with the Building Department about the approved product.

Our crew flags these heavier or lower-slope systems during the proposal stage, because they change both the engineering step and the inspection sequence compared with a standard asphalt shingle tear-off.

What Happens at Inspection

Longmont’s roofing guide states that ladders and mid-roof inspections are not required unless the roof is flat, but the permit holder must still call for the required final inspection once the roof is complete. Roof jacks and vents have to be raised to the level of the new roof and replaced, not just caulked around, before that final call goes in.

We treat the final inspection as the closing step of the job, not an optional courtesy call. The permit record, the completed flashing and vent work, and the finished roof all need to match before we consider the reroof done.

Nail Guns, Fasteners, and Flashing Details

Longmont allows nail guns when they are properly adjusted and used correctly, following the shingle manufacturer’s installation instructions. Fasteners must be long enough to penetrate the full roofing thickness plus a minimum of 3/4 inch into the decking, driven flush and perpendicular to the roof surface rather than over- or under-driven.

Flashing gets the same attention. Step flashing at sidewall junctions, raised flashing at roof jacks and vents, and drip edge around the full perimeter are part of the installation checklist our crew follows on every Longmont roof, since those are the details a reroof project is most likely to get inspected on.

How We Sequence a Longmont Roofing Project

We start by measuring the existing roof, counting layers, and checking slope, then confirm whether the project is a small permit-exempt repair or a full reroof under the 1-square rule. Once the scope is set, we select a shingle product with the required 110 mph wind warranty and confirm the ice-barrier and underlayment plan for the actual slope before filing for the permit.

On tear-off day, the deck is inspected and repaired as needed, underlayment and ice barrier go down per the slope tier, flashing and vents are raised and replaced, and the new shingles are installed to the manufacturer’s fastening schedule. The project closes with the roof jacks and vents finished correctly and the required final inspection called in before we consider the job complete.

Common Questions

Does re-roofing my Longmont house need a permit?
Yes. A permit is required to reroof a house in Longmont. Repairs to less than 100 square feet of the roof do not need a permit, but once repair or replacement passes that 100-square-foot line, the city’s 1-square rule requires the entire roof to be replaced.

How many layers of shingles are allowed?
Longmont allows only one layer of shingles on a residential roof. Overlaying new shingles over an existing roof is not allowed, and any roof with multiple existing layers must have all of them removed before the new roof is installed.

Does Longmont require ice-barrier underlayment?
Yes. Longmont requires Ice & Water Shield-type ice-barrier underlayment, installed according to the manufacturer’s instructions and code, in addition to standard felt underlayment sized to the roof slope.

What wind rating do shingles need in Longmont?
Per adopted code, asphalt shingles used in Longmont must carry a manufacturer’s wind warranty of 110 mph sustained wind, and 3-tab shingles are not allowed unless they are laminated.

Talk to Us About Your Project

Tell us your roof’s current material, approximate slope, and the area affected by damage or age. We will confirm whether your Longmont project is a repair or a full reroof, handle the permit, and build the schedule around the city’s underlayment, ice-barrier, and inspection requirements.