Materials

  • 18mm birch plywood
  • 1.5mm European walnut veneer
  • 55mm European walnut board (rough-sawn)
  • Wood glue
  • Hard wax oil
  • Parquet adhesive
  • Acrylic sealant
  • Vacuum press (plywood can also be veneered other ways)

Tools

  • Sawstop table saw
  • Jointer/planer
  • Router
  • Miter saw

Steps

Cut plywood to size

  • +5mm in depth
  • +20mm in width

Veneer the plywood

  • Trim the overhang flush

Cut veneered plywood to exact size

  • Per window!

Make the solid wood edging

  • Split solid wood into smaller pieces as early as possible
  • +20mm overhang (again, per window)
  • Glue on — not flush, but so it protrudes slightly above the surface (working from below later would require sanding a large area)

Finishing

  • Sand off the minimal overhang (80 grit)
  • Pre-sand (120 grit)
  • Rout chamfer/roundover
  • Final sand (180 grit)
  • Oil the surface

Installation

  • Apply parquet adhesive to the surface (shim if necessary for leveling)
  • Fill the joint with acrylic sealant (first tape off the sill and wall with painter’s tape)

Cost (€600 / 24 lm = €25/lm)

  • €300 Plywood
  • €100 Veneer
  • €200? Solid wood