The viola da terra is constructed of wood with a traditional guitar "hourglass" shape for the body, a fretted neck, and headstock supporting the tuners. Traditionally the viola da terra had wooden friction pegs inserted from behind the headstock, rather than the "watch-key" mechanism used on Portuguese instruments such as the Guitarra Portuguesa. Nowadays the Viola da terra usually has machine heads, similar to those of the classical guitar. What at first glance appears to be the bridge is actually just the support for the bridge pins, which anchor the lower end of the strings. The bridge saddle is a separate piece, which sits on the soundboard of the instrument, in front of the bridge pin plate. Like all Portuguese violas, the number of bridge pins does not match the number of strings, and often there are two or three strings on each pin. Scale length is about 540mm, shorter than the modern classical guitar scale of about 655mm. 22-24 metal frets are set into the fingerboard. One unusual distinguishing feature of the viola da terra is that the portion of the fingerboard which passes over the instrument's body is set flush with the top face of the soundboard. Another unique feature is the use of a pair heart-shaped sound holes, although the instrument is occasionally made with a single roundsound hole. The instrument is much lighter in construction than the classical guitar, using thinner tone woods, which supports a considerable volume of sound, despite the instrument's small size and light strings. There is also a smaller version called a Requinto.
Strings are generally of metal, and very light gauge, due to the instrument's light construction. The lowest pitched "A" and "D" strings are wound, as is the lowest "E" string on 15-string instruments. All other strings are of plain, unwound steel. With 12 strings, the lower 2 courses have 3 strings each, and the higher 3 courses have 2 strings each, all tuned in unison. It is tuned A3 A3 A2•D4 D4 D3•G3 G3•B3 B3•D4 D4. With 15 strings and five courses, each course is triple strung, and the tunings is A3 A3 A2•D4 D4 D3•G3 G3 G3•B3 B3 B3•D4 D4 D4; with 15 strings and six courses, the lower three courses are triple strung and the upper three courses are double strung: E3 E3 E2•A3 A3 A2•D4 D4 D3•G3 G3•B3 B3•D4 D4 -- similar to the Viola terceira.
