Shiplap vs. nickel-gap vs. tongue-and-groove: the differences

Shiplap, nickel-gap, and tongue-and-groove all end up as horizontal (or vertical) plank walls and ceilings, and the three names get thrown around like they're the same thing. They're not. The joint is different, the gap between boards is different, and that changes how the finished wall reads and how it handles seasonal movement. If you spec one and your client pictured another, that's a tear-out, not a touch-up.

Here's the plain version for builders: what each one is, where the famous gap comes from, and which one to reach for on a given wall or ceiling.

Shiplap

Shiplap boards have an L-shaped rabbet cut into the top and bottom edges, so each board overlaps the one below it — like clapboard, but indoors and flush. The overlap is what makes it shiplap. The gap you see between boards comes from a small, consistent reveal where the overlapped edges meet.

• The look — a clean, even shadow line between boards. The reveal is usually a touch wider than nickel-gap's, depending on the stock.
• Best for — accent walls, fireplace surrounds, mudrooms, and the modern-farmhouse look it's famous for.
• Watch for — that the wall behind it is flat and the studs are found. The overlap hides fasteners well but won't hide a wavy wall.

Shiplap is the workhorse of the accent-wall world — if you're weighing a plank wall against other feature treatments, our note on accent walls that add value puts it in context.

Nickel-gap

Here's the part that trips people up: nickel-gap is a type of shiplap, not a separate animal. It's milled with a built-in spacer on the joint that sets a precise, uniform gap between boards — roughly the thickness of a nickel, which is where the name comes from. You don't shim it; the profile does the spacing for you.

• The look — a tighter, more refined reveal than standard shiplap, dead-consistent because the milling controls it.
• Best for — clients who want the plank look but cleaner and more modern. Ceilings especially, where a crisp uniform line pays off overhead.
• Why crews like it — the built-in gap means you're not eyeballing or shimming spacing board to board. It installs faster and more consistently than setting your own reveal.

Nickel-gap is shiplap with the gap built into the milling. So when a client says 'shiplap,' ask which reveal they want — standard shiplap or the tighter nickel-gap look. That one question saves a tear-out.

Tongue-and-groove (T&G)

Tongue-and-groove is the different one. Instead of overlapping, each board has a protruding tongue on one edge that slides into a groove on the next. The boards lock together and seat flush — so depending on the milling, T&G can read as a nearly seamless flat surface or carry a small V-groove at each joint.

• The look — either a tight, almost-continuous plane or a crisp V-line at each joint, depending on whether you spec a V-groove profile.
• Best for — ceilings and porch ceilings especially, where the interlock keeps a long span flat and tight. Also stain-grade work, where the seamless seating shows off the wood.
• The structural edge — the tongue-and-groove interlock holds boards in plane and helps manage seasonal movement, which is why it's the traditional choice overhead.

T&G is also the go-to when planks meet a ceiling feature — running it between or alongside box beams is a classic move. Our note on box beams vs. coffered vs. tray ceilings covers how plank fields and beam grids work together overhead.

How to pick

Quick version:

• Standard shiplap — the classic accent-wall reveal, modern-farmhouse look, paint-grade walls.
• Nickel-gap — same idea, tighter and more consistent gap, great on ceilings; the built-in spacing speeds the install.
• Tongue-and-groove — flush or V-grooved, the strongest interlock, the choice for ceilings, porch ceilings, and stain-grade work where you want boards locked in plane.

All three live in the same corner of the finish package as wainscoting and beadboard, so they should be specced to talk to the rest of the room. If you're deciding between a plank field and a framed-panel look, our breakdown of wainscoting styles covers the other half of that decision.

Working out a plank wall or ceiling? See how we handle shiplap & T&G, look at how we tie it into beams & ceilings, or send us the plans and we'll bid the right profile for the wall.