PRODUCTION

 

 

The modern CNC machines, which ensure accuracy and speed of production, are used for the production of glued timber. In general, this technology consists of assembling the processed, kiln-dried and defects devoid elements, which are longitudinally glued by finger joints.  The individual elements are provided with a layer of proper glue and pressed together. In the case of joining the wood elements with glue, there is no disruption or weakening of the material, so the wood does not lose its strength. Every stage of glued timber production is subject to permanent quality controls (internal controls and inspections and external controls and inspections by independent agencies).

 

ECOLOGY AND SUSTAINABILITY

 

Wood is the only renewable structural construction material available in large quantities, it is easy to transport and work. The production of glued timber elements requires less energy input than other comparable components made of other materials. For the production of glued timber the organic glue, which does not cause any health risks, is used. In addition, the side-products of sawing such as bark, chopped wood and chips are used in full for the generation of energy and the production of paper or derived timber products.

 

ADVANTAGES

 

 

Due to available technologies the glued timber elements are able to achieve large load-bearing capacities and span distances up to several times greater than structural lumber. In comparison with the common structural lumber, the glued timber element exhibits greater dimensional and shape stability, improved fire performance and visual quality. Other distinct advantages include precise shaping, known strength classes determined in accordance with standards and any possible shape or dimensions of the beam.

In general, the biggest difference compared to structural lumber lies in the above-standard requirements set beyond the requirements of common standards used in the wood industry.

 

 

PRODUCTION

 

 

The timber used for production of KVH is sorted according to European standards. After cutting and sorting, it is kiln-dried to residual moisture content of 15 %, (+- 2%) which guarantee the dimensional stability of elements, little propensity for cracking and durability against attack of wood-destroying fungi. Timber elements are provided with finger joint and glued together with toxicologically safe and solvent-free PUR adhesives. The surface of KVH is planned and the edges are chamfered.

 

Special attention is paid to guarantee the highest quality standards. The marking „KVH“ is only permitted to be used on structural timber which is monitored by internal and external controls and inspections for compliance with the supplementary requirements.

 

STRENGTH CLASSES

 

The timber used for production of KVH is strength graded according to European standards. The individual sections are bonded together without affecting the structural strength of the structural element. The known strength classes help with design and static calculation of the construction. KVH is basically produced in strength class S10​ /C24​. The numeric value represents a characteristic value of the bending strength measured in N/mm2, respectively in MPa.

 

 

 

UTILIZATION

 

 

Mostly, KVH is used for the load-bearing frame constructions, ceiling beams and girders, roof constructions visible from the interior, pergolas and other construction.

KVH is permitted to be used for fields of application in which the use of common structural timber is permitted. For finger-jointed structural timber there is the additional restriction that it is only permitted to be used in Service Classes 1 and 2. KVH without finger joints is also permitted to be used in Service Class 3.

 

Download
the quality criteria of KVH

KVH

SOLID FINGER-JOINTED CONSTRUCTION TIMBER

Lenght 11,95 m

Thicknesses: 40 - 140 mm (stepwise in  20 mm gradiation)

Width: 60 - 280 mm (stepwise in  20 mm gradiation)

Download the Brochure and Data sheets about KVH

DUO and TRIO

GLUED SOLID TIMBER

Lenght 11,95 m

Thicknesses: 60 - 200 mm (stepwise in  20 mm gradiation)

Width: 100 - 280 mm (stepwise in  20 mm gradiation)

Download the Brochure and Data sheets about DUO/TRIO

 

PRODUCTION

 

Duobalken and Triobalken laminated beams are industrially manufactured products made of two or three planks of timber glued together by their flat side with the fibres running parallel. This way of gluing, in the combination with the low wood moisture content, results in a product which is even less susceptible to dimensional changes and cracking than KVH structural timber.

 

The timber used for production of Duo/Trio beams is sorted according to European standards. After sorting, wood elements are kiln-dried to residual moisture content of 12% +/- 2%, which guarantee the dimensional stability, little propensity for cracking and durability against attack of wood-destroying fungi. Dried lamellas are provided with finger joints and glued together with melamine adhesives. The surface of beams is planned and the edges are chamfered.

 

Special attention is paid to guarantee the highest quality standards. The used marking is only permitted to be used on structural timber which is monitored by internal and external controls and inspections for compliance with the supplementary requirements.

 

STRENGTH CLASSES

 

The timber used for production of laminated beams is strength graded according to European Standards. The position of the finished glue line – both vertically and horizontally – causes no differences in strength. According to certification, increased structural load bearing values can be calculated for Duobalken/Triobalken than for KVH. The fulfilment of the sorting criteria for sawn timber is in accordance with S10/C24. Duobalken and Triobalken are equivalent to glued laminated timber (BSH) with strength class GL24h.

 

 

UTILIZATION

 

Glued solid timber is only permitted to be used in Service Classes 1 and 2 (interior room climate or external climate under roofing). They are particularly well-suited to handle increased static loads. Examples in modern timber construction are when used as rafters, ceiling beams and uprights. Can be used also for pergolas and other visible constructions

 

Download the quality criteria of DUO and TRIO

BSH

GLUE LAMINATED TIMBER

Lenght 11,95 m

Thicknesses: 120 - 1600 mm (stepwise in  40 mm gradiation)

Width: 80 - 280 mm (stepwise in  20 mm gradiation)

Download the Brochure and Data sheets about KVH

 

PRODUCTION

 

Glued laminated timber is a
load-bearing material glued up
from suitably selected and prepared
pieces of wood either in a straight
or curved form with the grain of all
pieces essentially parallel to the
longitudinal axis of the member.
The laminations are longitudinally glued together using finger joints.

 

The raw material (spruce or Siberian larch) is kiln-dried and strength graded. The laminations are cut to the required length and placed on top of each other. To reduce internal stresses the laminates are turned so that the core sides face the same way throughout the cross-section. The outermost laminates are however always turned with the core side outwards. After longitudinal gluing using finger joints the flat sides of the laminates are planed and immediately glued. Then the pressure is applied. The laminates may be bent when the pressure is applied, producing cambered or curved forms.

 

By joining lumber end to end, face to face, the size of glulam is limited only by manufacturing capabilities and transportation method.

 

 

 

STRENGTH CLASSES

 

Glued laminated timber distinguishes according to strength classes. The standard strength classes GL 24c, 24h GL, GL 28c, and GL32c are offered. The numeric value represents a characteristic value of the bending strength measured in N/mm2, respectively in MPa and marking "h" and "c" indicates whether it is a homogeneous composition or a combined beam. Homogeneous cross-section consists of lamellas of the same strength class, while the combined cross-section is formed by lamellas of higher strength at the edges and lamellas of lower strength in the middle of the beam. Gluing has no negative effect on the mechanical properties of wood, element from glued laminated timber is from the static point of view evaluated as a complete profile.

 

Daily quality control testing of end-jointed lumber and adhesive durability test. Manufacture is supervised by the firm's controller (who records conditions of decisive importance to the quality of the products, such as the moisture content of the laminate timber, temperature and moisture content in the gluing hall, time of gluing and lifting).

 

 

 

UTILIZATION

 

Glued laminated timber elements are designed for statically loaded timber structures, even with the possibility of use in the third service class. In this case, some surface treatment is recommended. The application of glued laminated timber is such as roof trusses, joists, girders, beams, columns, constructions of bridges, footbridges, lookout towers and other external structures.

 

 

 

HOUT BAY HOUSE

 

Visit the Hout Bay House and take a look at spruce DUO and BSH used interior as well as at Siberian larch BSH used in the exterior of the house (without treatment). In the interior of this timber project we used 1200 mm thick spruce BSH.

 

Visit the House every Wednesday by appointment with Milan Detko.

 

 

MILAN DETKO

PRODUCT SPECIALIST

 

HWZ International SA

m.detko@hwzinternational.com

+27 (72) 946 8459

ZAIDA DAVIDS

OFFICE MANAGER

 

HWZ International SA

capetown@hwzinternational.com

+27 (76) 401 9120

GARETH HARE

DISTRIBUTION PARTNER

 

Ian Fuller Agencies

gareth.hare@ifatimber.co.za

+27 (84) 459 7788

All texts has been written by Ing. Eliska Oberhofnerova from Czech University of Life Sciences and copy rights belong to HWZ International SA, for any information regarding using texts from this website, please contact Klara Popovova (klara@holz.cz).