Fasten your deck!

There are a number of important points to consider when building a deck, not the least of which is what fastenings to use

Timber decks look great and are popular in both new builds and renovations. To ensure the deck’s structural integrity and the safety of those enjoying it, you need to make sure your fastenings are up to scratch.

MiTek’s BOWMAC brackets and LUMBERLOK fixings are specifically designed for use in New Zealand conditions.

BOWMAC brackets are structural fixings made to support the deck and are able to connect timber to timber, or timber to concrete.

LUMBERLOK fixings are used within the deck structure itself to tie and brace the deck. Both are available in either hot-dipped galvanised steel or stainless steel.

The durability table below will assist you in selecting the right fastening, depending on where you’re building the deck.

To help you build your next deck, we’ve also included a handy step-by-step guide to calculate bracing demand courtesy of BRANZ:

1. Select the earthquake zone from NZS 3604:2011 Figure 5.4 Earthquake zone maps.
2. Obtain the bracing demand from NZS 3604:2011 Table 5.8. Using half the value for light cladding for wall, roof and subfloor and 0–25° roof pitch, this is 15 × 0.5 = 7.5 Bracing Units (BU)/m².
3. Multiply the bracing demand by a factor (given at the bottom of Table 5.8) for soil class and earthquake zone.
4. Multiply the resulting value by the area of the deck to calculate the total number of bracing units (bus) required
   in each direction (NZS 3604:2011 5.3.1).

Example: For a proposed 10m² (5×2m) deck, with an earthquake zone three and soil class E.

From Table 5.8, the multiplication factor is 1.0, so 15 ×0.5 × 1.0 = 7.5 BU/m².

Multiply 7.5 BU/m² by the area of the deck to obtain the total bus required gives 7.5 × 10 = 75 BUs in each direction.