All too often a star-crossed collaboration can end up diminishing both parties, but when Robert Plant and Alison Krauss came together for 2007’s multi-award-winning Raising Sand, it had the opposite effect. The record’s rich and subtle readings of deep blues and country cuts allowed Plant to finally slip the rock god shackles, paving the way to Band Of Joy and Sensational Space Shifters, while Krauss was exposed to an audience outside her bluegrass fanbase. Now, 14 years later, the pair have reunited with producer T-Bone Burnett for belated follow-up Raise The Roof, which burnishes the diamond, confirming that even if Raising Sand was serendipitous it was certainly no fluke.

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As with its predecessor, the magic of Raise The Roof comes with the interaction of three elements: the voices of the two principles and the way they subtly enhance and embellish each other’s performances; the songs, drawn from a deep well of Americana that takes in blues, soul and country but sprinkled with gothic British folk courtesy of Plant; and the intricate but unobtrusive arrangements that Burnett ekes from a gifted band supplemented by unshowy turns from the likes of Buddy Miller, Bill Frisell, Emmylou Harris and David Hidalgo.

Each song seems subtle, even sparse, but with repeated listens the complexity of the arrangements starts to astound. Raise The Roof can sometimes feel like an impeccable and impossible feat of elaborate construction, an Escher illustration or Jenga tower of overlapping interests that would collapse in a heap if a single element were removed. Take The Everly Brothers’ “The Price Of Love”, one of the more familiar tunes on the album. Don and Phil placed the harmonies front and centre, backed by paint-stripper harmonica and a rumbling rockabilly rhythm. This band came at it askance, slowed down and spread out, with the melody crawling into view like Lawrence Of Arabia trudging through the desert. When the guitar solo arrives it sounds like an elephant ice-skating. The vocals are just as fascinating: Krauss on lead seems to be taking the tune in one direction, until Plant joins the chorus like a ghostly echo, pushing the song into a different dimension.

As you might expect, the vocals offer constant delight throughout. It’s rare for Plant and Krauss to tackle any song as a straight duet – opener “Quattro (World Drifts In)” by Calexico is one notable exception, introducing both singers as well as the album’s desert-stripped mescaline-trip ethereal vibe. More usually, one of the singers will take lead – but not always the one you might expect. Plant is a folk freak, so perhaps you might expect him to tackle Anne Briggs’s “Go Your Way”, but it’s still strange to hear Robert Plant of all people singing from the perspective of a woman left at home, mending clothes, cooking food and pondering if her man has gone to war. The austerity of Briggs’ original is transformed into something with more jangle, and Plant’s delivery is from the heart; he might be the most unlikely homemaker in the history of rock, but when he creaks “I want to die” you can well believe it. It’s Plant’s best single moment on the record.

Then shortly after comes Bert Jansch’s “It Don’t Bother Me”, another Plant favourite but this time with Krauss on lead, her clear and mesmeric vocals rubbing against Marc Ribot’s spidery lead and the song’s metallic drone but ironing out some of Jansch’s wrinkles without weakening the meaning. Plant’s harmonies add definition, but it is Jay Bellerose’s fine drumming that brings this one home. Bellerose plays on every track and Ribot all but one; the core band is rounded out by either Viktor Krauss (Alison’s brother) or Dennis Crouch on bass and multi-instrumentalists Russell Pahl and Jeff Taylor, with additional contributions from Burnett himself.

The band’s ability to weave between genres without sounding like anything other than themselves is impressive. When Krauss takes sensual lead on a lush version of Merle Haggard’s understated gem “Going Where The Lonely Go”, the band’s relaxed Nashville mode is one of the few times they seem to be anywhere near a comfort zone. Lucinda Williams’ “Can’t Let Go” (written by Randy Weekes) – with Plant on lead – has the band imitating The Shadows or Link Wray; it follows immediately from Plant’s reading of “Searchin’ For My Baby”, originally a million-seller on Chess by Bobbie Moore and here delivered as a straight soul ballad but with no sense of jarring dislocation as the band effortlessly switch between styles. Allen Toussaint’s “Trouble With My Lover” was originally a classic northern soul track sung by Betty Harris; the Raise The Roof version has more of a desert strut, with Bellerose’s percussion running through it like a heartbeat. The vocal is also markedly different. Where Harris was sharing her pain with the word in a belting soul style, Krauss seems to be talking to herself, internalising the emotion until she gets to the sultry refrain “when he puts his arms around me…” when the suppressed passion explodes into outright lust, supplemented by Plant’s seductive echo.

Krauss’s other stand-out performance is on “Last Kind Words Blues”, a stunning country blues written by the mysterious Geeshie Wiley, a blueswoman who cut six sides in 1930 but about whom little is known. Krauss comes at it like bluegrass, bold and true and pure, highlighting the spiritual side of secular blues and emphasising the stark poetry of the lyrics: “If I get killed, if I get killed, please don’t bury my soul/I prefer just leave me out, let the buzzards eat me whole”. It’ll send a shiver down the spine.

Plant’s chance to channel the blues comes on “You Led Me To The Wrong”, originally a white country blues by Ola Belle Reed. Plant’s pent-up desire to unleash the inner rock god contrasts neatly with Burnett’s mysterious arrangement, where the only man allowed to let rip is Stuart Duncan on fiddle. That restraint is what makes it work, allowing the song to escape blues rock clichés and focus on the ambiguous lyrics, which – like almost every song on the record – is about love gone bad. The narrator is awaiting execution after shooting his best friend over a love affair – “a man has to fight, for what he thinks is right, even if it puts him in the ground”. One of the small pleasures on Raise The Roof is the way Plant and Krauss frequently swap gender roles; this one is slightly more complicated as Reed was a woman singing from the perspective of a man, and Plant now restores the male gaze.

The album’s one non-cover is another blues piece, “High And Lonesome”,  one of the album’s rockier moments. Plant shares a writing credit with T-Bone Burnett having contributed lyrics for a song that developed from Burnett’s improvised riff. It’s the most Zep-worthy moment on the record but still slots neatly among the other songs  in terms of sensibility and sound, partly thanks to the way Krauss’s wily harmony undercuts the main vocal.

Raise The Roof closes with another heavier track, “Somebody Was Watching Over Me”, which has Emmylou Harris on backing vocals and was written by singer-songwriter Brenda Burns. The track was recorded as wizened blues by Pop Staples on his 2015 posthumous record produced with Jeff Tweedy. The original – very different – version was recorded by Maria Muldaur as a gospel number with Bonnie Raitt and Mavis Staples on backing vocals. There’s something significant in the way a single song and songwriter can touch on so many genres of American roots music, and the version on Raise The Roof sits somewhere between the two previous recordings, with Plant and Krauss delivering it almost as a duet, their first since the album’s scene-setting opener. Between those two tracks, much emotional and musical territory has been covered. Let’s hope it isn’t another 14 years until the next one.