Longmont's older housing stock in Old Town and Kensington often features asphalt shingles installed over skip sheathing that can hide leaks until water reaches drywall. Snow from the Front Range accumulates on north-facing slopes and melts unevenly, pushing water under lifted tabs at valleys and around plumbing vents. We cut out saturated underlayment sections, install new ice-and-water shield strips that extend past the leak point, and match shingle courses so the repair blends without creating new weak lines.
Boulder County wind events and hail from summer storms frequently crack granules on three-tab shingles, allowing meltwater from Left Hand Creek microclimates to wick upward. When we find this pattern we replace the damaged course plus the row above and below, then check step flashing at chimneys and walls for corrosion that lets water travel laterally into Sunset neighborhood attics. Homeowners who try sealant alone usually see the same spot leak again after the next freeze-thaw cycle.
We always verify attic ventilation during leak calls because Longmont's warm days followed by cold nights create condensation that mimics roof leaks on insulation. Proper ridge vent balance and baffles keep moisture from collecting at the ridge where many Kensington homes have limited soffit intake. This step prevents callbacks that occur when only the exterior shingles are addressed.
Technician insight
In Longmont the thing that catches most people out with Shingle Roof Leak Repair is ice dams forming along the eaves of older Old Town homes where attic insulation blocks soffit vents; the meltwater backs up under the shingles even when the roof itself looks intact.
Kensington roof leak after March snow
Water stains appeared on a kitchen ceiling after a warm spell melted heavy snow. We traced the path to a corroded valley flashing where two roof planes met. The valley was opened, new metal and extended underlayment were installed, and the surrounding shingles were replaced to match. No further leaks occurred through the next winter.
Shingle Roof Leak Repair Services We Offer
✓Valley Leak Repairs
Remove failed valley flashing, install new metal with extended underlayment, and reseal shingles to stop water traveling along seams common on Longmont roofs.
✓Chimney Flashing Replacement
Replace corroded step and counter flashing around masonry chimneys that allow snowmelt to enter attics in Old Town and Downtown homes.
✓Plumbing Vent Boot Repair
Remove cracked rubber boots on vent pipes, install new boots with proper sealant, and check surrounding shingles for hidden rot.
✓Ice Dam Leak Stops
Add ice-and-water shield along eaves and improve attic ventilation to prevent recurring leaks from snow accumulation on Sunset and Kensington roofs.
✓Ridge Cap Leak Repair
Re-secure or replace ridge cap shingles and underlying ridge vent sections where wind-driven rain enters during Boulder County storms.
✓Skylight Curb Sealing
Re-flash skylight curbs with new step flashing and membrane to stop leaks that appear after heavy spring runoff near Roosevelt Park.
Shingle Roof Leak Repair Cost in Longmont, CO
| Service | Typical Range | What Affects It |
|---|---|---|
| Single shingle patch repair | $250–$450 | Small isolated leak on one slope |
| Valley section repair | $600–$950 | Includes new flashing and underlayment |
| Chimney flashing replacement | $550–$850 | Step flashing on one side of chimney |
| Multiple leak locations | $900–$1,600 | Two or more separate entry points |
Ranges are typical for Longmont, CO and confirmed with an exact written quote before any work starts.
How it works
- 1
Inspection
We climb the roof and attic to trace water stains back to the entry point, checking valleys, flashing and penetrations specific to Longmont's shingle profiles.
- 2
Documentation
Photos and notes are taken of affected areas in neighborhoods like Kensington so the repair plan matches the exact slope and exposure.
- 3
Material Removal
Damaged shingles and underlayment are cut out cleanly without disturbing sound sections, preserving the roof's remaining life.
- 4
Repair Installation
New underlayment, flashing and matching shingles are installed with manufacturer-recommended overlaps for local wind and snow loads.
- 5
Final Check
Interior and exterior are inspected after the repair, and attic ventilation is verified to reduce future condensation issues.
Pricing
Upfront quotes after on-site inspection; price depends on access, extent of underlayment damage and whether multiple slopes are involved.