In an episode of “Grand Designs,” a couple wants to expand a tiny cottage into a three-bedroom family home. One member of the couple, Gregory Kewish, has the idea to use panels of a high-tech wood—called cross-laminated timber—in a new and experimental way, as structural components. His engineer is not so enamored of the idea, and quits. But Kewish perseveres. We see him crawling across the cottage’s roof one night, in pitch darkness and pouring rain, moving the massive wooden panels into place as his partner, Rebecca Sturrock, looks on worriedly.

Building a house can possess a person, become a kind of madness. This is a theme that runs through “Grand Designs.”

In this case, the payoff is worth it. When host Kevin McCloud visits the completed house, it is dark and angular on the outside, and inside, more hygge than a Scandinavian ski lodge, with walls, ceiling, and furniture made of honey-colored wood. “It’s one of the nicest homes I’ve ever, ever been in,” says McCloud, sincerely, as Kewish and Sturrock break down in tears of pride and relief.

Nearly two decades into its run on Britain’s Channel 4, two seasons of “Grand Designs” are now available on Netflix, finally plugging a hole in American TV programming for smart, watchable shows about architecture. It’s a genre the British excel at. In the U.K., architecture shows don’t make you feel like you’re eating your spinach—the way a multipart PBS documentary on Frank Lloyd Wright might—but they rise well above the junk food of “House Hunters.” (No offense, HGTV fans.) For instance, there’s Jonathan Meades’s jump-cut architectural criticism on the BBC, or the 2011 miniseries The Secret Life of Buildings.

“Grand Designs” is more middlebrow and easygoing. The format is simple. Each episode tracks the building or renovation of a house from the first pour of the foundations to settled domesticity, focusing on the hopes and tribulations of the owners (usually a couple). The question is always: Can they pull it off? It’s not a spoiler to reveal that they always do, more or less.

McCloud with Peter and Chard Berkin, who built themselves a horseshoe-shaped house (Netflix)

Despite the lack of suspense,Grand Designs” works beautifully, for two reasons. First, the producers obviously take great care in the projects they select. Many, but not all, could be described as high design, midwifed by architects in thick-framed glasses. But others involve a technical challenge or human twist. In one episode, a man builds a huge house out of cob, an earth-and-straw mix he believes is the construction material of the future. In another, a flying instructor and his trapeze-artist girlfriend build a hangar-like home on an airfield. Some of the projects have big budgets, others quite modest ones. (Another iron rule of “Grand Designs” is that all projects go over budget.)

What you don’t see on the show is a parade of granite countertops and whirlpool baths. “Grand Designs” rejects the asset-value mindset, emphasizing the unique fit of house to occupant, and the necessity of responding to site and context. It portrays architects as problem-solvers, not trend forecasters. The fact that it includes architects at all is notable: When was the last time you saw one on TV? Appropriately, the architects get less screen time than their clients, underscoring the point that architecture’s purpose is to serve the people who use it.

The second key to the show’s appeal is McCloud, who is terrific at presenting architecture to a general audience. To explain a structural principle, he’ll make a quick model out of boxes, tennis balls, or chocolate bars. On site, he asks the contractors about techniques they’re using, and sometimes lends a hand himself. McCloud treads the line between cheerleader and critic, remaining skeptical during the build-out but invariably declaring the finished house a success. (After watching enough episodes, though, you can tell when he really likes it.)

Architect-farmer Patrick Bradley (right) designed and built a house made out of four shipping containers in Northern Ireland. (Netflix)  

A Cambridge graduate and former lighting designer, McCloud has become something of an architectural crusader in the U.K. In 2007, with “Grand Designs” a confirmed hit, he launched his own development company “to make homes that lift the spirits,” in contrast to “the way identikit volume housing [is] built,” according to the website of the company, HAB (short for Happiness, Architecture, Beauty). Since then, HAB has worked with leading British architects to build small Modernist villages of houses, townhouses, and apartments in western England.

This design-for-all philosophy animates some episodes of “Grand Designs,” and they’re often the best ones. In the “Tiverton” episode of Season 11, Jon White, a Royal Marine who lost three limbs in Afghanistan, and his wife Becky build a house that is lovely, attuned to their needs, and totally cancels out the plastic-handrail image of “design for the disabled.” As they walk up their gently inclined staircase—made with clear acrylic risers that have a bit of give, to suit Jon’s prostheses—McCloud comments, “Many of the things that you’re doing for your convenience are actually for the convenience and comfort of everybody.” That’s exactly the goal of universal design.  

Like Jon and Becky’s house, “Grand Designs” smuggles serious architectural concepts into a deceptively pleasant package. Will McCloud ever crack American TV? Probably not: he’s a middle-aged guy with a face unsmoothed by Botox. More’s the pity, because “Grand Designs” does a better job than anything I’ve watched at demonstrating how good architecture improves people’s lives.