# T-Lock Shingle

> An asphalt shingle with a T-shaped profile that hooks into neighbouring shingles instead of relying on a sealant strip; production ended around 2006.

- URL: https://roof.wiki/t-lock-shingle/
- Topic: Roofing Materials
- Also known as: interlocking shingle; T-lock; lock-down shingle
- Regions: North America
- First published: 2026-11-02 · Last reviewed: 2026-11-02
- Cite as: "T-Lock Shingle." roof.wiki. https://roof.wiki/t-lock-shingle/

## Key facts

- **Fixing principle:** Interlocking shape plus nails; no adhesive strip
- **Production ended:** Around 2006

A T-lock shingle is a type of interlocking asphalt shingle shaped roughly like a letter T. Instead of being held down by a factory-applied adhesive strip, each shingle hooks under the edges of its neighbours, and the interlocking pattern, together with the nails, resists wind lift.

## Appearance

A T-lock roof has a distinctive woven or basket-weave look, with each shingle's narrow lower tab locked between the shingles on either side. They were often used to re-roof directly over an existing layer of shingles because the interlocking pattern bridged irregularities.

## History

Interlocking shingles were developed in the mid-20th century, when wind resistance of strip shingles was a concern and before self-sealing adhesive strips became reliable. Self-sealing strips came into general use in the 1950s, and laminated shingles later offered higher wind ratings. According to the US home-inspection association InterNACHI, manufacture of T-lock shingles ended around 2006, although many roofs covered with them remain in service.

## Repair issues

Because T-lock shingles are no longer made, damaged roofs cannot be patched with matching material. Insurers and adjusters sometimes treat a damaged T-lock roof as unrepairable for that reason, and replacement with a different shingle type is usually required. The interlocking design also makes individual shingles difficult to remove without damaging neighbouring pieces.

## Related forms

Other interlocking asphalt designs included "Dutch lap" and hexagonal shingles. All have largely disappeared from the market in favour of self-sealing strip and laminated shingles.


## Sources

1. Mastering Roof Inspections: Asphalt Composition Shingles, Part 6 — InterNACHI. https://nachi.org/asphalt-comp-shingles-part6-60.htm
2. Asphalt shingle — Wikipedia. https://en.wikipedia.org/wiki/Asphalt_shingle