A builder posting under the handle Novucraft gutted a cracked, waterless pool shell and rebuilt it into a full gym-sauna-cold-plunge suite, and the time-lapse of that transformation has pulled in about 5 million views, according to the creator’s own TikTok video. The clip opens on a shell full of dead leaves, standing rainwater and crumbling plaster, the kind of backyard eyesore that usually gets written off as a demolition project. By the final cut, that same footprint holds a rubber-floored workout area, a cedar-lined sauna box, and a sunken cold plunge built straight into the deep end. You watch a hole in the ground become the most-used room in the house.
@novucraft I Built a Secret Luxury Wellness Room Under My Backyard
What the shell looked like before the gut job
The starting point is the whole story: an in-ground pool with no water treatment, structural staining down the walls, and enough standing debris to make it a mosquito problem rather than a swimming spot. Deferred pools like this typically face two grim choices, according to HomeGuide’s pool remodel cost data, which puts a full resurfacing and structural remodel at a national average of $17,500, with major jobs running $5,000 to $30,000 before a single amenity gets added. Filling the hole in outright carries its own excavation and fill-dirt costs. Building inside the existing shell instead of removing it skips both of those price tags and reuses the one expensive part already in the ground: a code-built concrete basin.
Turning the shallow end into a gym floor
The workout area sits where the shallow end used to be, built up with a framed subfloor and rubber matting so the space reads as flat ground rather than a pool bottom. That’s the section of the shell with the least depth to frame over, which is also why most pool-to-room conversions start there. Novucraft’s footage shows exposed studs going up before the drywall and equipment go in, giving viewers the structural view a finished renovation reel usually skips entirely.
A sauna box and a cold plunge sharing the same footprint
The deep end became the cold plunge, using the pool’s own depth instead of buying a separate tub, a detail that matters because a standalone plunge setup with a chiller alone typically runs $1,000 to $3,000 for a mid-range unit, per NordVital Wellness’s 2026 cold plunge pricing guide. A separate framed sauna box sits along one wall. A custom-built sauna room, rather than a prefab kit, typically costs $4,300 to $34,000 depending on size and finish, according to IceColdTubs’ home sauna cost breakdown. Building both into a pool shell that already has plumbing and electrical rough-in nearby doesn’t erase those costs, but it removes the excavation and foundation work a from-scratch build would need.
Why the math favors converting over filling in
Pools that sit empty for years lose their pumps, liners and often their permits to legally operate as pools at all, so homeowners inheriting one usually aren’t choosing between a nice pool and a wellness room. They’re choosing between a wellness room and an empty hole. Reused this way, the shell’s concrete walls, drainage and existing plumbing lines do double duty as the bones of three separate amenities that would otherwise be priced and built one at a time. That’s the appeal driving the view count as much as the finished reveal is.
Does any of it actually pay off at resale
A well-installed home sauna alone can add $5,000 to $20,000 to a property’s market value, with typical return on investment landing between 40% and 55% depending on climate, according to Haven of Heat’s resale data on home saunas. Buyer demand backs that up: 42% of homebuyers consider a sauna a desirable feature, per a National Association of Realtors survey cited in the same report. A cold plunge and a home gym don’t carry the same third-party ROI research, but stacking three amenities into a shell that would otherwise sit as dead space, rather than pricing them as three separate additions, is what makes the numbers work even before resale enters the conversation.
The room reflects a broader shift in what backyards are for
Home gyms, saunas and cold plunges have moved from hotel-spa novelty to backyard standard over the past few years, and the cost guides bear that out. A premium infrared sauna alone can run $4,500 to $16,000, per IceColdTubs, while a fully plumbed cold plunge system with an electric chiller lands at $3,000 to $10,000 or more, according to NordVital Wellness. Stacking all three into recycled square footage, instead of building a new addition for each one, is the version of that trend that actually fits a typical suburban lot. The old pool didn’t need to be demolished. It needed a different job.
