Summary and Characteristics
Doors made of natural birch plywood may experience warping or bowing due to climatic variations, especially humidity. To minimise these effects in doors over 200 cm in height, we install adjustable TN100 tensioners, designed to correct deformations and maintain door alignment over time.
1. Introduction: Wood as a Living Material
The birch plywood we use in our LAMINADO and LINÓLEO ranges is a 100% natural material, composed of thin wood veneers glued in cross-laminated layers. Although treated with natural oils and protective products, it remains a “living” material that reacts actively to environmental changes, especially humidity.
For example:
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In Madrid, summer relative humidity ranges between 20–30%.
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In Barcelona, it can reach up to 90%.
These variations cause dimensional movement in the wood, such as warping (longitudinal twist) or bowing (arching), which are more pronounced in tall and narrow elements like vertical cabinet or tall unit doors.
2. What Are Tensioners and How Do They Work?
TN100 tensioners are metal accessories that are discreetly integrated into the structure of the door when it exceeds 200 cm in height. They are specifically designed to:
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Correct slight warping or bowing caused by humidity.
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Maintain the door’s flatness and alignment.
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Allow post-installation adjustment, without disassembling the door.
3. Instructions
The central element of the tensioner is an adjustment component that is not a conventional screw. It has limited travel and is designed to apply gradual pressure.
Tools Needed
- 8 mm hex key
Recommended procedure:
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Locate the access hole to the adjustment mechanism.
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Turn the hex key half a turn (180°) to the left.
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Repeat this adjustment once a week, for 6 weeks.
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Do not force the mechanism. The wood must adapt progressively.
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Check each week if the door is straightening.
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Do not exceed the travel of the tensioner; abrupt or excessive adjustments may damage the mechanism or the door.
📌 Important: All tensioners on the same door must be adjusted in the same direction, to avoid uneven stress.
4. Why Progressive Adjustment Matters
Birch plywood is not rigid or homogeneous like plastic or metal, and it responds slowly to applied force. Applying too much pressure at once can:
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Prevent proper correction.
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Cause cracks or breakage.
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Damage the tensioner.
Therefore, we recommend a weekly progressive approach, allowing the wood to adapt gradually and return to its natural position without compromising the structural integrity of the furniture.