Shiplap vs. Tongue & Groove Siding: Which Is Right for Your Project?

The Short Answer: Shiplap and tongue and groove are both wood siding profiles, but they connect differently. Shiplap boards overlap with a small shadow gap between them, while tongue and groove boards lock edge to edge for a flush, smooth surface.

That single difference in how the boards meet shapes the look, the installation process, and how each one handles weather. Shiplap gives you a defined shadow line and a rustic look. Tongue and groove gives you clean lines and a tighter seal. The right pick depends on where the wood goes, the style you want, and your budget.

Shiplap vs. Tongue and Groove: The Main Difference

Both profiles start as solid wooden boards milled with shaped edges. The biggest difference is the joint.

What Is Shiplap?

Shiplap uses an L-shaped cut called a rabbet joint along each edge. When two shiplap boards meet, their cut edges overlap like puzzle pieces. The name comes from old shipbuilding, where overlapping planks formed a tight outer shell, and you will still see it written as two words, ship lap. As exterior shiplap cladding, the overlap forms a tight seal that channels wind-driven rain out and down. Shiplap is usually face-nailed, so on close inspection, you may see filled nail holes along each board. Shiplap can run horizontal or vertical.

What Is Tongue and Groove?

Tongue and groove uses an interlocking design instead of an overlap. One edge of each wood plank has a protruding tongue. The opposite edge has a matching groove. The tongue of one board slides into the groove of the next, locking the boards together. This tight fit pulls the boards flat and hides the fasteners inside the joint. The result is a flush, smooth surface with thin seams and no visible nail head. Because each fastener can be hidden inside the joint, the face shows no exposed nail holes. Tongue and groove can run horizontal or vertical.

How Each Profile Performs

The joint does more than change the look. It changes how the wall handles moisture, movement, and weather.

Weather and Moisture

Wood expands and contracts as humidity changes. Shiplap's overlapping edge gives boards room to move while still shedding water, since the overlap channels rain down and out. That makes shiplap forgiving on exterior walls. Tongue and groove forms a tighter seal because the boards interlock. This tighter seal blocks drafts and resists water well, which is why it is popular for ceilings, soffits, and refined exterior siding. The tradeoff is that a locked joint leaves less visible room for movement, so proper drying matters more. Both profiles perform best when the wood starts at a low moisture content.

Look and Style

Shiplap has a more rustic feel. The shadow gap creates a repeating line of definition across the wall, adding texture and depth. Tongue and groove leans modern. Its flush face produces clean lines and a smooth surface with minimal joints. Choosing between the two often comes down to personal preference. Some people want the visible rhythm of shiplap planks. Others prefer the continuous, near-flat surface of groove siding.

Installation and Cost

A few choices shape how exterior siding is installed and what it costs.

Installation Methods

Both profiles attach to a prepared exterior wall over a moisture barrier. Some installs add furring strips to create a ventilated rainscreen gap that helps the wall drain and dry. Shiplap is usually face-nailed, which is quick and forgiving for first-time installers, and its overlapping edge sheds water while giving each board room to expand and contract. Tongue and groove is often blind-nailed through the tongue, so the fasteners stay hidden behind a flatter, more finished face. In fire-prone areas, a flame-retardant coating adds protection for either choice. For a full walkthrough, see our guide on how to install wood siding.

Horizontal vs. Vertical Layout

Either profile can run horizontal or vertical. Horizontal rows give the traditional siding look and make a wall read wider. Vertical boards draw the eye up and shed water quickly. The orientation is mostly a style call, since both profiles seal well in either direction.

What Affects Cost

As a general rule, tongue and groove runs a little higher than shiplap. Cutting both a tongue and a groove takes more milling than shiplap's single rabbeted edge, and that extra step tends to show up in the price. A few other factors move the total:

• Project scope matters most. A small wall uses far less material than wrapping a full exterior, so the total scales with the square footage you cover.

• Outdoor add-ons cost extra. Optional moisture and fire protectants add to the price up front, especially on exterior projects facing the sun and weather.

• Order size can lower the rate. Larger siding jobs may qualify for bulk pricing, which reduces the cost per board.

Reclaimed wood also sits in a different category than fiber cement and other manufactured siding. It trades factory uniformity for natural character. For an exact number on either profile, request a quote through the form on our siding page, and the team will price your specific project.

Centennial Woods: Reclaimed Shiplap and Tongue and Groove Siding

Centennial Woods mills both profiles from reclaimed wood pulled off Wyoming snow fences, where spruce, fir, and pine planks weather outdoors for 7 to 10 years. That natural aging brings the moisture content down to 4 to 8 percent before milling, which helps the boards stay flat after they go up.

Our shiplap siding has overlapping edges milled to an 11/16-inch thickness with a 4 1/2-inch reveal, in standard 8- and 12-foot lengths. Our tongue and groove siding shares the same 11/16-inch thickness and 4 1/2-inch face width, in lengths up to 12 feet, for a flush face. Both ship in eight weathered finishes and can be ordered with Centennial Seal for UV and moisture protection or our flame-retardant coating for fire protection.

Want to see how each profile looks on your own home? Request your free siding sample box, or contact our team for help choosing the right profile for your project.