Solid structural timber
Construction timber is a term for refined Bauschnitthölzer . The letter combination KVH is a protected product name for special construction timber with defined quality properties that go beyond the requirements of DIN 4074, in accordance with an agreement between the Bund Deutscher Zimmermeister (BDZ) and the Monitoring Association for Solid Construction Timber
A distinction is made between solid structural timber for visible installation (KVH Si) and that for invisible installation (KVH NSi). In the case of the former, the demands on the optical surface quality are even higher.
The increased requirements compared to conventional construction timber relate in particular to the following criteria:
- Wood moisture content : KVH is supplied with a defined wood moisture content of ω = 15 ± 3%. Since this moisture rate is close to the expected equilibrium moisture content in the installed state , the probability of subsequent deformations is minimized. (DIN 4074 permits a wood moisture content of ω = max. 20% for standard construction timber of quality S10TS. In practice, however, this is often exceeded due to a lack of quality control during the delivery of wood.)
- Type of incision: The formation of shrinkage cracks is reduced by means of heart-separated, if desired also heart-free incisions . A heart-separated incision is a cut through the pith of the wood, with a heart-free incision even the core is cut out.
- Surface quality : planed and chamfered (KVH Si) or leveled and chamfered (KVH NSi). (DIN 4074: rough sawn)
KVH can be supplied in longer lengths than conventional construction timber, as it can be extended by means of finger joints . Spruce , fir , pine , larch and Douglas fir are permitted types of wood for KVH .
Due to the advancing industrialization (away from the regional, small sawmill, towards the central industrial sawmill), the industrially manufactured building material KVH is gaining steadily increasing importance as a replacement for the classic construction timber.
In addition, double or triple glued beams, so-called DUO or TRIO beams, are manufactured for dimensions from 12 cm wide. This is done for reasons of dimensional stability and to avoid difficulties in drying the core of larger cross-sections.
Web links
- Solid construction timber on KVH.de
- Solid construction timber on Materialarchiv.ch: - Extensive material information and pictures
Individual evidence
- ↑ wood quality. On Holzfragen.de, accessed on January 3, 2019.