Garage Door Repair Glossary

This glossary decodes the jargon of garage door repair so Londonderry homeowners can spot trouble early and ask the right questions before a worn spring or failing sensor leaves you stuck outside in a Londonderry winter. Know the parts, know the risks, and know when to call us.

Garage doors in Londonderry’s older homes face unique wear: brick lintels settle, masonry sheds dust onto tracks, and historic wood panels swell with coastal humidity. Before you reach for a wrench or a quote, learn the language your door speaks. Whether you’re in the heart of town or tucked along Mammoth Road, these terms explain what’s under the hood—and when to call a pro. Explore our full services to see how we handle Londonderry’s trickiest garage-door quirks.

Torsion spring

A tightly wound metal coil mounted above the garage door that counterbalances the door’s weight, letting it open and close smoothly. Unlike extension springs, torsion springs unwind slowly and store energy; if one snaps, it can fling debris like a bullet—always replace both springs at once. In Londonderry’s older homes, rust and fatigue shorten their life faster than in newer builds. See our full list of services.

Extension spring

A long, stretched spring running parallel to the door tracks that helps lift the door by extending and contracting. These springs are cheaper but riskier: a broken one can snap violently, especially in unheated garages where cold metal becomes brittle. We recommend upgrading to torsion springs for safety and longevity in Londonderry’s four-season climate. Learn more at request a free estimate / contact us.

Track

The metal rails—usually two vertical and one horizontal—that guide the door as it moves. Bent or misaligned tracks cause jerky operation and can derail rollers. In Londonderry’s brick homes, settling foundations often warp tracks over time; a quick visual check every season prevents costly repairs.

Roller

Small wheels that ride inside the tracks, carrying the door’s weight and reducing friction. Nylon rollers last longer than steel in humid summers, but Londonderry’s salt-spray winters corrode metal parts fast. Worn rollers squeal and can pop off the track, leaving your door stuck halfway.

Opener

The electric motor that automates opening and closing, paired with a chain, belt, or screw drive. A failing opener in an older Londonderry home might struggle with a heavy wooden door or a misaligned track. Always pair opener upgrades with a safety inspection to avoid crushing hazards.

Photo-eye sensor

A pair of infrared beams mounted near the floor that detect obstructions and stop the door from closing. If dirty or misaligned—common after Londonderry’s muddy winters—they can trigger false reversals. Test monthly by waving a broom in the beam’s path.

Limit switch

A safety device that tells the opener when the door has reached its fully open or closed position. If set incorrectly, the door may stop short or slam shut, damaging tracks or brickwork. In Londonderry’s older garages, sagging headers can skew the switch’s calibration.

Weatherstripping

Flexible seals along the door edges that block drafts, pests, and moisture. Brittle or missing strips let Londonderry’s damp air rot wood panels and corrode metal tracks. Replace every few years, especially before winter sets in.

R-value (insulation)

A measure of how well the door resists heat flow; higher R-values (like R-12 to R-18) keep garages warmer in Londonderry’s cold snaps. Older single-layer doors often have R-values below 6, costing you hundreds in heating bills. Upgrading to insulated panels also quiets noisy operation.

Cable drum

A grooved pulley at the top of the door that winds and unwinds the lift cables as the door moves. If the drum is cracked or the cable jumps off, the door can crash. In Londonderry’s historic homes, vibration from nearby roads can loosen drums over time.

Bottom seal

A thick rubber or vinyl strip attached to the door’s bottom edge that seals the gap between door and driveway. Worn seals let water pool against brickwork, causing efflorescence and masonry damage. Replace it every 3–5 years to protect your Londonderry home’s exterior.

Travel module

The electronic brain inside modern openers that controls speed, force, and safety features. A faulty module can make the door hesitate or reverse unpredictably—especially problematic on uneven Londonderry driveways. We diagnose these with specialized tools to avoid guesswork.

Trolley

The part that connects the opener to the door, pulling it along the tracks. A slipping or bent trolley causes jerky starts and uneven wear. In Londonderry’s older garages, loose mounting brackets often let the trolley sag, leading to misalignment.

Manual release

A red-handled cord or lever that disengages the opener, letting you open or close the door by hand in a power outage. Always test it twice a year; a stuck release can trap you inside during a Londonderry storm. Keep the handle within easy reach.

Brick lintel

The horizontal brick or stone above the garage door that supports the masonry above. Cracked or sagging lintels—common in Londonderry’s 19th-century homes—can warp tracks and misalign the door. We inspect lintels during every service call to prevent costly structural repairs.

Masonry liner

A thin panel installed behind the door to shield brickwork from dust, moisture, and impact. Without a liner, garage-door vibration can crack mortar joints in Londonderry’s older brick garages. We recommend adding one when restoring vintage doors.

Frequently Asked Questions