In the late 1990s brothers Alec and Joel Thibodeau formed String Builder as a songwriting partnership with an acoustic-based sound reminiscent of earlier traditions. After documenting their initial work on 4-track machines, the brothers met up with Pete Donnelly (The Figgs, Graham Parker, NRBQ, Tommy Stinson, Mike Viola & The Candy Butchers, Soul Asylum), who had built an analog recording studio at his apartment in Providence, Rhode Island. Pete produced sessions for String Builder in 1998 and 1999, engineering everything on reel-to-reel tape.

The resulting collection became String Builder's debut album, Mortar, which the band self-released as 50 cassette tapes in 1999 on the eve of its two-month tour of the USA on Greyhound buses. Simultaneously, Grimsey Records issued the song "Lakeview" as a single on 7-inch vinyl. Most tracks on Mortar have spare arrangements: harmony vocals and acoustic guitars. Some feature the expanded instrumentation of Alec and Joel's electric guitars, electric bass, harmonica, lap steel and fiddle -- plus Pete's contributions on air organ, drums and percussion.