Photograph courtesy of Drew Farrell

There's little outward sign of it - he's as thin as a rake - or in his fragile, unembellished voice, but Alasdair Roberts has stamina to burn. This week the folk musician and singer unveils his eighth solo full-length record which, added to multiple releases as Appendix Out and a long list of collaborations both live and on record, stands as testament to his tenacity in an increasingly uncertain industry.

The self-titled album contrasts in form and content with A Wonder Working Stone, the 2013 long-player issued under the banner of Alasdair Roberts And Friends, which featured regular collaborators gathered from the Glasgow underground, such as Stevie Jones (whose Sound of Yell album Brocken Spectre features Roberts on hurdy-gurdy), Ben Reynolds of Two Wings and fiddler-for-hire Rafe Fitzpatrick. Clocking in at 67 minutes with individual cuts scraping the ten-minute mark, it took effort to digest.

Alasdair Roberts, though, is a less daunting proposition - ten songs, most bidding farewell after four minutes or so, with the focus on Roberts' nimble fingerstyle guitar playing and his voice. Additional players are restricted to vocal quartet The Crying Lion, who include Alex Neilson and Lavinia Blackwall of Trembling Bells, Donald Lindsay on tin whistle and Alex South on clarinet and bass clarinet. The cover image, a drawing of Roberts by the celebrated artist Alasdair Gray, is as lucid and as modest as not only the music it adorns but also the creator of said music.

"It's almost like the new record happened by accident," says Roberts as we convene in his flat on the southside of Glasgow a few days into the new year. "I had days booked in the studio to work on another project and the person I was going to be working with cancelled so I was like: 'I'm going to use this time to make decent demos of ten songs.' Then I kept working on them and got people in to do overdubs and sent them to the label and they liked it, so I was like: 'OK, that's the next record then.'

"At a certain point I decided it's a good contrast to the previous record, which is kind of big with big arrangements. This one's a lot more stripped down and it's more or less a solo record. That's not to say I don't want to work with the band again. I was terrified to tell those guys that I'd made this record without them." Roberts smiles. "I was like: 'Oh shit. How am I going to tell them? They're going to hate me.' But they were fine with it. They're all busy with their own stuff as well so the band hadn't played together for months and months, and part of me was like: 'Yeah … Screw those guys, then.'" He laughs and takes another sip of coffee. I help myself to another Ferrero Rocher ("a gift from a neighbour" he's quick to point out).

Roberts released his first record - Appendix Out's The Rye Bears A Poison, issued by Drag City, the Chicago label with which he remains - in 1997. Does he challenge himself with every new album?

"You don't want to make the same record twice, so yeah it's a conscious decision to make the record different. On A Wonder Working Stone the shortest song was four-and-a-half or five minutes and the longest was like ten minutes - crazy lengths, which meant it didn't get much radio play - so on this new one the songs are quite concise."

As followers of Roberts' career will anticipate, the new material harks back to bygone traditional songs, reanimating their spirit for the modern age.  

"I'm immersed in traditional song so that's always the basis for the song - I'll adapt a tune from a traditional song or a turn of phrase or a conceit from a traditional source and take it from there. I'm interested in making new work, new music, but I'm also interested in the old music that informs it. I like the idea of the new work being located in the continuum of tradition but also being outside it. It's almost like an alternative reality."

The symbiosis between Roberts' original songs and traditional music has flowed steadily throughout his work, picking up pace and growing inexorably after he stepped out under his own name in 2001 with The Crook Of My Arm. Collections of self-authored songs such as Farewell Sorrow (2003) and Spoils (2009) were both followed by gatherings of Scots ballads - No Earthly Man (2005) and Too Long In This Condition (2010) respectively. Meanwhile, the singer has found a new outlet for his obsession with traditional music.

"I go through periods of being really engaged with traditional song and ballads in particular," he elaborates. "When it comes to traditional song, my main area of interest is the narrative ballads, the 'muckle sangs', so I research those and sing them and then after a period of immersion in that I'll do some writing. And because of the immersion the influence of traditional songs is felt in my own writing. I'm slowly writing new songs since finishing this new record and I'm also involved with a group called the Furrow Collective which has become an outlet for the traditional songs I'm attracted to. I'm juggling these two things - finding traditional repertoire for that band but also continuing my own writing."

An instructive parallel can be drawn between Roberts' fascination with murder ballads and one of his musical touchstones, Nic Jones, whose irreverent reimaginings of broadside ballads soared skywards on the twin thermals of superlative guitar work and a sonorous, commanding voice. Roberts was first alerted to Jones while growing up in the Stirlingshire town of Callander, where he submitted to the common ritual of trawling through his father's vinyl vault. Alan Roberts was different from most fathers, however.

"My dad was a musician and booked bands like the Battlefield Band and the Tannahill Weavers, and he used to play with Dougie MacLean [perhaps best known for writing the song 'Caledonia']. He was friends with guys like Alex Campbell so that was there when I was growing up.

"When I was in my late teens I started digging around in his record collection and discovering guys like Nic Jones and Steeleye Span. He had Nic Jones' third and fourth albums, the ones that came before Penguin Eggs, which I listened to a lot when I was 18 or 19. They're quite hard to come by now.

"The first two albums are accomplished but the debt to Martin Carthy and guys like that is very clear and the singing style is more typical of that period of folk revival, but his voice and playing improved remarkably on The Noah's Ark Trap and From The Devil To A Stranger and on into Penguin Eggs. His singing is so effortless and smooth."

Which other figures does Roberts hold in high esteem? "Singers I particularly like are Dick Gaughan and Martin Carthy. I could name a lot of older traditional singers who, as a Scottish singer, it's important to engage with - Jeannie Robertson, Lucy Stewart, Lizzie Higgins, Stanley Robertson, Duncan Williamson. A lot of traveller singers are my favourites, like Sheila Stewart and her mother Belle."

If those names are less than familiar, don't fret. Roberts' knowledge of Scottish singers and storytellers from Aberdeenshire and beyond is panoramic, fuelled in part by visits to Edinburgh university's School of Scottish Studies. Has he ever thought of formalising his interest in Scottish traditional music?

"I've thought about it," he replies. "I've thought about becoming more involved academically in a place like the School of Scottish Studies but …" He trails off before adding, drily, "Maybe I'm enjoying being in the world of rock and roll too much." We both laugh. Playing hurdy-gurdy for Sound of Yell? "Aye!" he shoots back.

Perhaps Roberts' childhood experience of music education still haunts him. Though he took private lessons from the late jazz guitarist Laurie Hamilton, studying music at school held little appeal. "I liked the teachers but I didn't like the way music was taught," he says. "It seemed very square. Then when I moved to Glasgow I was playing with people who were studying music and it seemed to me that they had very square attitudes towards music that were either a result of the education they were undergoing or the reason for their attraction to that kind of education. They were afraid of dissonance and things. But then they were young. I was young. We were all young …"

How, then, does Roberts grasp the rhythmic and melodic complexities that run like a seam through much traditional folk music? Is it purely by ear? "Pretty much," he says. "I might listen to traditional singing - that can be quite simple, or ostensibly simple, because the best of those singers have a very refined and complex art - but I also listen to things which are more obviously complex, like baroque music or earlier polyphonic vocal musics or Bach or whatever. You feel that maybe by listening to music of greater compositional complexity it will rub off on you.

"I've listened to a lot of lute music by John Dowland [English Renaissance composer] and things like that, and there's a German composer Sylvius Leopold Weiss who composed exclusively for lute, so I've listened to his music and that approach to playing a stringed instrument has rubbed off on me - the fingerstyle thing is influenced by baroque lute music."

Those less familiar with the work of such long-dead figures can be rest assured that Roberts' new album is a work of profound accessibility, at least in the eyes of its maker. "It feels like a very slight, simple record to me," he says. "I've seen some reviews and they've been nice, mostly, which has been good because I wasn't sure what people would make of it. I thought maybe they'd think it was too simple. Maybe it's more complex than I realise.

"One review talked about some kind of perceived Christian element to it. Some people approach things from those kind of angles. There might be something in that. I'm a son of the manse - my mum's a minister - so maybe there's a preoccupation with spiritual issues and metaphysical themes. I see myself more as a metaphysical or spiritual artist than an overtly political artist. That probably comes through in the songs."

What Roberts stoutly doesn't see himself as is avant-garde, despite how certain commentators might regard him. In March 2010 he found himself on the front page of The Wire. "I'm like: 'What the fuck am I doing on the cover of this experimental music magazine?' It felt bizarre. And then it was almost like the work dried up for a few months." He laughs.

"I remember writing to another musician, a friend of mine - I don't know if I should say the name of the person - who'd also been on the cover of The Wire. Och, I'll say it, it was Will Oldham, and the theme of it was: the work seems to have dried up since they put me on the cover of The Wire. And he wrote back and was like: 'It's the kiss of death.'" Roberts laughs again, long and hard. Morbid humour, you might say.

He'll be touring his new record in the UK in February and March, though he admits it could be a struggle. "I recorded the album over a year ago and it already feels quite old," he says. "A lot of my personal circumstances have changed since then so the subjects and particularly the personal relationships I was addressing on the record are in completely different states now. It's funny trying to access those emotions or getting in touch with the original impulses that gave birth to the songs when things have changed so much.

"I always feel that in order to make a new piece of work you have to grow into a different person, and I'm almost waiting for it to happen. You can't be the same person you were when you made the last one so I feel like I'm currently in this chrysalid state where I'm waiting to burst out as a new being to make the next piece of work."

Whatever the outcome, it will be a metamorphosis worth beholding.

Alasdair Roberts is out now via Drag City. Roberts' UK tour begins at the Kitchen Garden Cafe in Birmingham on February 26; head to his website for full details and tickets