Requirements of Duobalken® and Triobalken®

The specification of quality criteria which exceed those required by building regulations first came in 2003 with an agreement on Duobalken® and Triobalken® beams. To minimize cracking and deformation from shrinkage caused by drying, specifications for moisture content and the type of cutting were set down. Other criteria are concerned mainly with the dimensional stability and the appearance of the timber.

Requirements to be met by Duobalken® and Triobalken® beams in accordance with the general technical approval of the German building authorities as assessed by the Deutsche Institut für Bautechnik (Z-9.1-440 dated 30/01/2009).

Grading criterion

Requirements to be met by Duobalken® and Triobalken® beams

Remarks

Exposed areas

Non-exposed areas

Technical standard

General technical approval of the German building authorities No. Z 9.1-440

 

Modulus of elasticity II to fiber

E0,mean = 11.600 N/mm²

Higher value compared to solid timber C24 in accordance with DIN 1052.

Grading class compliant with DIN 4074-1

Min. S10TS;
C24 in accordance with DIN 1052

The decisive strength and stiffness properties are given in DIN 1052.

Moisture content umsub>

Max. 15%

Precondition for gluing

Dimensional stability
of the cross-section

DIN EN 336, Dimensional stability class 2
w ≤ 100 mm   ± 1 mm
b > 100 mm ± 1,5 mm

The dimensional stability for the longitudinal dimensions must be agreed between the customer and supplier.

Twisting

≤ 4 mm/2 m

ZIn comparison:
DIN 4074-1:S 10: ≤ 8 mm/2 m

Longitudinal warping

≤ 4 mm/2 m

In comparison:
DIN 4074-1:S 10: ≤ 8 mm/2 m

Surface quality

Planed and chamfered

Leveled and chamfered

The right-hand sides (sides adjacent to the heart) must face outwards

Finishing of the ends

Trimmed perpendicular

 

Finger-jointing

DIN EN 385