Rationel Durability

All Rationel composite windows and doors consist of at least 90% “heartwood” is on all exterior faces. Heartwood from the centre of slow grown trees is very durable. There are moves to increase it’s usage to all parts of the frame.

Rationel Sustainability

Rationel Sustainability

Rationel Durability

Rationel Durability

Rationel Technical Performance

Rationel Technical Performance

All timber is treated in accordance with System ECO2. It is a “eco-friendly” water based 3-layer system. Finger jointed “Engineered” Timber as seen here uses the better parts of the timber, this creates more stable, more durable windows and doors that are free from blemishes and knots and more resistant to movement.

  • Moisture levels should be around 12 - 15%
  • Annual ring distance: Max 4mm
  • Density: Min 500kg/m3
  • Impregnation added with Flowcoat
  • Primer added with Flowcoat
  • Top finish is spray-coated either translucent or painted
Rationel Durability
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