Tongue & Groove
Tongue and groove wood offers a clean, continuous look for walls, ceilings, siding, and other architectural applications. At Mason’s Mill & Lumber, we offer a variety of wood species, profiles, and finishes for both interior and exterior projects.
What Is Tongue & Groove Wood?
Tongue and groove, commonly referred to as T&G, is a milling profile that allows adjoining boards to fit together using a tongue on one edge and a matching groove on the other.
This connection creates a consistent surface with clean lines and a uniform appearance. Depending on the profile and wood species, tongue and groove can complement traditional, rustic, or modern architectural styles.
From traditional Southern Yellow Pine to thermally modified hardwoods and softwoods, our team can help you find the right material for your project.
Browse Tongue & Groove Stock
Ayous / African Mahogany — CUTEK® Extreme Clear Finish
Ayous (Triplochiton scleroxylon), also known as Obeche, African Whitewood, Samba, or Wawa, is a lightweight tropical hardwood native to the forests of West and Central Africa. In its natural, unmodified state, Ayous has a pale cream to light yellow heartwood with a straight to slightly interlocked grain and a medium-to-coarse texture with good natural luster. It's frequently grouped with — and sold alongside — African Mahogany because of its similar workability, dimensional characteristics, and the way it accepts stains and finishes to achieve rich, mahogany-like tones.
Ayous is prized for several reasons that make it well-suited to architectural and millwork applications: it's remarkably lightweight (roughly 24 lbs/ft³), which eases handling for vertical siding, ceiling, and overhead installations; it has low shrinkage and good dimensional behavior once properly dried; and its clear, knot-free character grades produce a smooth, uniform surface ideal for high-visibility finish work. In its natural state, Ayous is considered non-durable to moderately durable against decay, which is why exterior applications require a quality penetrating finish to protect the wood and extend its service life.
Each board is finished with CUTEK® Extreme Clear, a penetrating oil specifically formulated to stabilize exterior wood from within. Unlike surface coatings that sit on top of the board and eventually peel, crack, or flake, CUTEK® carries its oils deep into the wood fibers where they work continuously to reduce moisture movement — the primary cause of cupping, checking, warping, and end-splitting. This is especially important for a species like Ayous, whose natural durability benefits significantly from a stabilizing oil. Because Cutek penetrates rather than films, maintenance requires no sanding or stripping — just clean the surface and reapply when it looks dry. The clear formulation adds no pigment, allowing the Ayous's natural cream-to-honey tone to show through initially before gradually silvering to a soft gray patina if left unmaintained with a colortone.
Because Ayous can react with iron and galvanized fasteners (causing black staining), stainless steel fixings are required for installation. Pre-drilling is also recommended, as the wood can be brittle.
Ideal for architectural siding, feature walls, soffits, porch ceilings, interior paneling, sauna applications, and covered outdoor living areas where a lightweight, workable hardwood with a refined appearance is desired.
Specifications
| Spec | Detail |
|---|---|
| Species | Ayous (Triplochiton scleroxylon) |
| Also Known As | Obeche, African Whitewood, Samba, Wawa; often sold alongside African Mahogany |
| Origin | West and Central Africa |
| Modification | None — natural, kiln-dried |
| Finish | Cutek Extreme Clear (penetrating oil) |
| Finish Type | Oil-based, non-film-forming |
| Color | Natural pale cream to light yellow; darkens slightly with age; accepts stains beautifully to achieve mahogany-like tones |
| Grade | Clear grade available; virtually knot-free |
| Grain / Texture | Straight to slightly interlocked grain; medium-to-coarse texture; good natural luster |
| Janka Hardness | ~440 lbf |
| Average Dried Weight | 23.8 lbs/ft³ (380 kg/m³) — lightweight |
| Specific Gravity | 0.32 (basic), 0.38 (12% MC) |
| Modulus of Rupture | 8,680 lbf/in² |
| Elastic Modulus | 934,000 lbf/in² |
| Shrinkage | Radial 3.1%, Tangential 5.3%, Volumetric 8.7% (T/R ratio 1.7) |
| Natural Durability | Non-durable to moderately durable — finish required for exterior use |
| Workability | Machines and finishes well; sands smoothly; accepts stains and oils evenly |
| Applications | Exterior siding (with finish), feature walls, soffits, porch ceilings, interior paneling, sauna walls/ceilings, millwork, trim |
| Fixings | Stainless steel required — Ayous reacts with iron and galvanized fasteners; pre-drilling recommended |
| Maintenance | Clean and re-oil with CUTEK® Extreme as needed — no sanding or stripping required |
| Sustainability | FSC-certified options available |
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Interior & Exterior Applications
Tongue and groove wood is used across a variety of residential and commercial projects. The right species, profile, and finish will depend on the location and intended use.
Interior Walls & Ceilings
Create warm, continuous wood surfaces for living areas, offices, and architectural accents.
Porches & Covered Outdoor Areas
Bring natural wood character to covered ceilings and other protected outdoor spaces.
Exterior Siding & Cladding
Use exterior-rated tongue and groove materials for architectural siding and cladding applications.
Soffits & Architectural Details
Add consistent wood detailing to roof overhangs, entryways, and architectural features.
Custom Milling& Finishing Options
Every project has different requirements, and standard profiles may not always be the right fit.
Mason’s Mill offers custom milling services for tongue and groove wood in select species, dimensions, and profiles. Our Mill Applied Finishes service also provides finishing options to help prepare materials before delivery.
Share your project specifications with our team, and we can help determine the available options.
Frequently Asked Questions
Tongue and groove boards connect through a tongue on one edge and a matching groove on the other. Shiplap boards use overlapping rabbeted edges. Both can be used for walls, ceilings, and select exterior applications, but they create different joint details.
Yes. Tongue and groove can be used for exterior applications when the wood species, profile, and finishing system are suitable for the intended exposure. Thermally modified wood is one option for exterior siding and cladding.
Mason’s Mill offers options including Southern Yellow Pine and select thermally modified species such as Ash, Spruce, and Pine. Availability varies by profile and product.
Yes. Many tongue and groove products can be painted, stained, or finished with a clear coating. The appropriate finish depends on the wood species, exposure conditions, and desired appearance.
Yes. Our custom millwork team can produce select tongue and groove profiles based on project specifications, wood species, and dimensions.
Yes. Samples are available for select tongue and groove products through our online Sample Shop, allowing you to review the material before placing a larger order.
Find the Right Tongue & Groove Wood for Your Project
Whether you’re working on an interior ceiling, exterior cladding, or a custom architectural detail, Mason’s Mill & Lumber can help you explore available wood species, profiles, and finishing options. Contact our team to discuss your project or request a quote below.