1. Seite 1
Modern screw connectors
Design and use in CLT, Gluelam and LVL
By Michael Koenig

2. Topics
Pictures of projects
• Expo Roof
• Airport Paris
• Mt Ruapehu
• Waitomo Caves
Modern screw connectors
• Partial thread and full thread and field of use
• Head shape and recess
• Samples of connections
• Pre drilling
• Corrosion issues
Technical information
• Where to get information from

3. The roof of the Expo 2000 in Germany
approx. 10,000,000 screws are in use here, to ensure the permanent
strength of the wood.

4. Charles de Gaulle Airport, Paris

5. Cologne Zoo Elefant House

7. Steel to Timber connection

8. Knoll Ridge Cafe, Whakapapa NZ

9. Knoll Ridge Cafe, Whakapapa NZ

10. Waitomo Caves Visitor Centre

11. Waitomo Caves Visitor Centre

12. Modern screw connectors
Modern screw connectors today are:
• Self-tapping screws for use in timber structures
• No pre drilling is required (except hardwoods)
• The main characteristics are:
- thread: full or partial threaded
- head shapes

13. Modern screw connectors
Full thread or Partial thread
Full thread
- for long screws no clamping effect
- with remarkably high load bearing capacity
in tension as well as in compression
- inclined screws can work as framed truss
Partial thread
- with clamping effect, pull together
- clamping effect is depending on head shape
and size

14. Modern Screw Connectors
Main head shapes and recess
Washer headCountersunk SPAX T-STAR plus recess for
best driving home performance

15. Modern screw connectors
Countersunk head
• Main use for full threaded screws
• Flush counter sinking in timber
• Small head diameter for reduced visibility
• For partial threaded screws small load bearing
capacity in tension due to head diameter
• Can be used also in counter sunk steel plates for steel to
timber connections

16. Application examples: Countersunk Screws
Wall fastening, timber frame construction
Secure joining of wall
elements, for example

17. Modern Screw Connectors
Washer head
• Best use for partial thread screws
• Plain contact to timber
• Big head diameter
• For partial threaded screws high load bearing
capacity in tension due to big head diameter

18. Application examples: Wascher Head Screws
Fastening rafters, purlin
Fastening the rafters, pulled
tightly together using the
washer head screw.
No purlin anchors / triple grip
necessary
High wind uplift load bearing
capacity

19. Modern Screw Connectors
Cylindrical head
• Only use for full thread screws
• Flush counter sinking with timber, or
slightly deeper sinking possible
• Very small head diameter for reduced visibility
• Is not recommended for use in
steel to timber connections
• Also data on screw reinforcement available from Expan

20. Application examples: Fully Threaded Screws
Transverse tensile reinforcement in accordance with DIN 1052:2008
Reliable alternative to bonded
reinforcement boards and glued
thread rods
Work can be performed by any
carpenters shop
No bonding approval required
Work can also be reliably performed
on site (e.g. restoration of buildings)

21. Roller coaster Liseberg Stockholm, Sweden
Split control of engineered dowel connections

22. EXPAN Quick-Connect
Rafter
Sleeves
(steel rods inside)
Screws
Bearing plates
Column

23. Design of connection detail
Spacing of screws

24. CLT – standard details
Corner joint
Exterior wall
partial thread
sealing tapes for
air tight shell
Picture: Building with cross laminated timber
of Studiengemeinschaft Holzleimbau e.V.

25. CLT – standard details
Ceiling connection
Platform framing
partial thread
sealing tapes for
air tight shell
Picture: Building with cross laminated timber
of Studiengemeinschaft Holzleimbau e.V.

26. CLT – standard details
Roof connection
Eave detail
partial thread
sealing tapes for
air tight shell
Picture: Building with cross laminated timber
of Studiengemeinschaft Holzleimbau e.V.

27. CLT – standard details
Wall connection vertical
Partial thread with connection splice plate
Picture: Building solutions of Stora Enso

28. CLT – standard details
Ceiling connection
with connection splice plate
Partial thread
Picture: Building solutions of Stora Enso
j

29. CLT – standard details
Picture: Building solutions of Stora Enso
Ceiling connection
Full thread with reinforcement, full thread

30. CLT – standard details
Picture: Building solutions of Stora Enso
Top bearer connection with steel beam
Full thread
J
v
J
v

31. CLT – standard details
Picture: Building solutions of Stora Enso
Top bearer connection with upper CLT wall
Full thread

32. Pre-Drilling
Do not exceed maximum drive torque
Pre-drill size should be shank Ø of the screw
Pre-drilling as a locating guide for easy installation

33. Corrosion control
Zinc: for internal use only
Hot dip galvanize: for external use in low corrosive areas. (Low
tensile fasteners only)
Delta-Seal: ideal for treated timber in low corrosive areas
Stainless Steel: in exposed high corrosive areas

34. Technical Information
www.spaxpacific.com
Download the European Technical approvals
Download a SPAX Design guide (based on EC5 and ETA)
E-mail details to info@spaxpacific.com
Full range of SPAX timber construction program available in Australia and
New Zealand
Design software available soon

35. THANK YOU VERY MUCH