Rectangular construction wood, planed from robinia wood

The construction wood is planed to size from selected wood. The wood contains only knots that are well grown together. Planing creates a flat surface of the wood. However, minor roughness at grown-together knots or other areas with differing wood structure cannot be avoided.

Robinia wood cannot be nailed - it is much too hard for that. If you manage to drive in a nail, the wood may split because it does not give in. Even when using wood screws, you must pre-drill. Stainless steel screws are recommended. Only galvanized screws will start to rust outdoors sooner or later, while the Robinia wood will last for decades.

By choosing Robinia wood, you are opting for a wonderful product of nature. This is not an artificial, standardized material. Each piece has its individuality, its liveliness through certain irregularities. These only become defects if they impair functionality.

Dimensional tolerances: The specified thickness measurements apply with a tolerance of 0.3 mm (at the time of delivery). Due to drying, the thickness measurements can decrease by up to 6%. The specified length is accurate to 2 mm.

Quality features: Evenly grown, straight wood; at most small, grown-in knots in low numbers.

Warping and cracks: Wood is alive because its moisture content - depending on the ambient humidity and climate - affects the dimensions and internal stresses of the wood. Across the grain direction (radial, tangential), the dimensions can change by up to 6% in practice, while in the grain direction (axial) the change is very slight.

Larger internal stresses are released by the wood warping and cracking. This must be taken into account. (Our ancestors, whose main material was wood, did this; we tend to forget it today.)

The above is even more true the harder the wood is; Robinia wood is the hardest among woods.

How the wood warps and cracks is not concretely predictable. The drier the wood is, the greater the volume shrinkage and the more and larger the cracks are generally. There can be several cracks, or it can concentrate on just one large crack.

On the other hand, the thickness of the wood is crucial. The thicker the wood is, the greater the absolute volume shrinkage that is "compensated" by the cracks. From wood thicknesses of 6 cm, cracks are unavoidable, no matter how carefully it is dried.

The ambient climate can vary greatly. Unprotected or covered outdoor areas, unheated or heated indoor areas, sunny or shady sides.

Since we do not know the ambient climate at the place of use, we deliver sawn timber air-dried, i.e., with a wood moisture content of about 20%, no more. Then there will be at most minor cracks - in relation to the thickness (see above). In a shady place, the wood will hardly dry out further.

Rapid further drying of the wood in the sun or in a protected place amplifies the stresses in the wood. Then the wood can warp and crack far beyond the unavoidable extent. If you store the wood, please do so in a shady, cool place and secured.

Cracks do not mean a reduction in the strength, load-bearing capacity, and lifespan of the wood.