DIN 68800-2:2012-02

This standard specifies preventive constructional measures for ensuring durability of building components made of wood or wood-based panels. It applies in connection with DIN 68800-1 for the erection of new buildings and for modernization, renovation or repair of buildings. The standard applies to load-bearing building components made of wood and wood-based panels. Application of this standard is recommended for non-load bearing building components. Constructional measures for the purpose of this standard are an essential prerequisite for long-term functionality of a construction. Under certain external conditions, these constructional measures can individually ensure durability of building components made of wood or wood-based panels or lead to a lower use class. For this purpose design examples are given in Annex A of this standard. Through the constructional measures according to this standard a detrimental change of humidity of the wood and wood-based panels is avoided and as a result deformations due to swelling and shrinkage are kept within acceptable levels and the usability of the construction regarding these deformations is ensured. A distinction is made between basic constructional measures and special constructional measures. Basic constructional measures shall be applied in every case, even if this does not change allocation to a use class according to DIN 68800-1. By applying special constructional measures according to clauses 6 to 9, structural components can be allocated to use class GK 0 provided that the basic constructional measures according to clause 5 do not exclusively allow allocation to use class GK 0. For wood-based panels, the fields of application are specified in clause 10. With respect to DIN 68800-2:1996-05, the use classes specified in DIN EN 335-1 were taken into account and a distinction between basic constructional measures and special constructional measures was introduced. The specifications in 5.2 regarding moisture content in service have been considerably extended and building components without ground contact subjected to weathering have been taken into account for the special constructional measures to avoid structural damage by wood-destroying fungi in 6.2.2. According to 6.3 b), the exclusive use of glued laminated timber, cross laminated timber, artificially dried building timber or wood-based panels with a moisture content u > 20 % in service is sufficient to avoid structural damage by insects. In clause 7 on construction principles for external building components fulfilling the conditions of use class GK 0, structural decks over an exterior space and hall constructions have been taken into account. In clause 8 on construction principles for internal components fulfilling the conditions of use class GK 0, interior walls, floors between rooms with the same climatic conditions and ceilings above cellar rooms have been included. Regarding the fields of application of wood-based panels, DIN EN 13986 has been taken into account in clause 10. The use of wood-based panels which have been treated with wood preservatives (former wood material class 100G) is no longer necessary within the framework of the standard. Examples for constructions for which conditions of use class GK 0 are fulfilled are depicted in Annex A. The committee responsible for this standard is NA 042-03-02 AA "Baulicher Holzschutz" ("Construction protection of wood") at DIN.