Aquila Building SuppliesAquila Building SuppliesVancouver Island wholesale · Sakura Trading
Mountain cabin clad in engineered cedar tongue-and-groove, with snow on the ground

Engineered Western Red Cedar

Engineered tongue-and-groove

A clear vertical-grain cedar face laminated over a finger-jointed core. Made in Parksville, BC by ST Wood Products. Sold in two face profiles: Fineline and Micro V.

  • Clear VG cedar face
  • Finger-jointed core
  • Kiln dried
  • Exterior adhesive
  • Fineline or Micro V

Construction

How it is built

The board is a laminate of three parts: a clear cedar face, an exterior-grade adhesive layer and a finger-jointed softwood core. The blank is then milled to the tongue-and-groove profile, so the joint is cut through the whole laminate.

1 Clear vertical-grainWestern Red Cedar face 2 Exterior-grade adhesivebonds face to core 3 Finger-jointed, kiln-driedbacker core 4 T&G profile milled throughthe whole laminate

Join the three layers, or separate them again.

  1. 1Clear vertical-grain Western Red Cedar face
  2. 2Exterior-grade adhesive
  3. 3Finger-jointed, kiln-dried backer core
  4. 4T&G profile milled through the laminate

Exploded view of one board. Not to scale; layer thicknesses are schematic. The shallow V-joint chamfer on the tongue edge is drawn as on the Micro V profile.

The face

A clear, vertical-grain Western Red Cedar veneer. It is the only species Aquila offers in engineered T&G. Clear cedar is used only where it is seen.

The core

Kiln-dried softwood, finger-jointed from shorter lengths. Lower-grade and short fibre goes here, where it is not visible.

The profile

After lamination the blank is milled to the Fineline (fine-line flush face) or Micro V (micro V-joint) profile, so the tongue and groove run through face, adhesive and core together.

Clear VG face

Engineered bevel siding sample, face side, showing clear vertical-grain cedar with fine straight grain lines (same laminate family as the T&G)

Finger-jointed core

Close-up of finger joints between core lamellas in the cedar laminate

Performance

Why engineered cedar stays flat

Solid flat-sawn boards move unevenly across their width as moisture changes, and the movement shows up as cupping. Cupped boards open the joint and let water in. The engineered board is built to move less, and to hold what movement remains in check.

The laminate stays flat through wet and dry cycles, so the T&G joint stays closed. Cedar's natural extractives resist decay. Finish with a breathable stain such as Sansin or similar, or leave the cedar to weather.

Solid flat-sawn board cup Growth rings cross the width; the board cups as it moves. Engineered T&G Vertical-grain face, adhesive line, core segments with alternating grain.

End-grain view, schematic. The cup is exaggerated for clarity.

Five reasons it performs better than solid T&G

  1. No continuous plane of weaknessThe finger-jointed core has no single long grain line. Short sections with alternating grain counter each other instead of pulling the board into a cup.
  2. Vertical-grain faceEdge grain moves about half as much across the width as flat grain, and the core restrains it.
  3. Kiln dried before laminationBoth layers are dried before they are bonded, so the board is at equilibrium when installed.
  4. Clear face, no knotsThere is nothing to loosen, bleed or check, and lengths run long without defects.
  5. Less clear cedar per boardLower-grade and short fibre goes into the core, so the same log supply gives more clear coverage than solid clear T&G.