In an old house the walls are wavy, and leveling them is expensive and time-consuming. I just want to glue or install something to make it look normal. What would you suggest - 3D panels, wainscoting, or something else?
Shiplap really does work, but I wouldn't call it a universal solution. It all depends on what you're planning next and how wavy the walls are. For minor waves, the frame handles it fine, but if the dips are more than an inch or so, you'll have to adjust the wooden slats to level with shims - that complicates the installation.
3D panels won't hide wall unevenness the way shiplap does, because they only press against the surface at certain points. They look good on fairly flat surfaces, add interesting texture, but won't hide waves. Laminate on the wall, by the way, is also an option - it attaches to a frame like shiplap, looks more modern, easier to maintain. Plastic panels seem cheap, but they actually hide cosmetic flaws pretty well if you're not constantly touching them with your hands.
If the walls are really wavy and you don't want to deal with leveling a frame - consider fabric wallpaper on a fleece backing. You stretch it over a frame or glue it straight on, and it visually evens out the wall thanks to soft shadows and texture. It's not panels, but it looks expensive, and the waves are barely noticeable. The main thing is picking the right pattern and color so they don't draw attention to the surface.
# Translation from Russian to English
I have wavy walls in my cottage too, and I've tried different options. Wooden planking is the most reliable way. It's attached to a framework that hides all the irregularities, and the boards themselves look neat and practical. The main thing is to let the planking acclimate in the room for a couple of days before installation, otherwise it dries out later and gaps appear. You attach it through wooden slats that you've leveled beforehand, and the wall's waviness just stops mattering.
3D panels work too, but there's a catch. They need a more perfect surface for gluing - if the unevenness is more than an inch or two, the panels will fall off. And sometimes they look a bit cheap, though it depends on the quality. If the walls aren't too wavy, you can try it - but it's more of a cosmetic fix.
There's also cork covering or fabric panels, but they're less practical to maintain. If you want something quick and reliable - I'd still recommend wooden planking or assembled MDF panels on a framework. They forgive irregularities, last a long time, and are easy to repair. Plus it costs less than leveling the walls.
I'm voting for shiplap, but I'll add an important point about the batten. The thing is, you need to put soundproofing or at least a dense film under it - otherwise air will circulate between the wall and the panels, and it'll get even colder in the house. Plus insects will move in if you don't seal the gaps. The battens are mounted on dowels straight over the uneven spots, and then the shiplap is attached to them - super simple and fast.
The only downside to shiplap is that it needs treatment and can darken over time if it's not lacquered. But if you get quality euro-shiplap with a protective coating, it'll last a long time. From a couple years of using it, I can see it's no fussier than any other finishing method.
3D panels are also a viable option, but they're more expensive and require more careful installation - the unevenness still shows through the relief. For an old house, shiplap is more practical simply because houses continue settling over time, and a rigid batten system tolerates that, while solid panels can start to crack.
Log into answer.
