Decks

Hello. I am going to be building a deck and the the soil that it will be going on is rated 'H class' (Highly reactive). At this stage I am planning to have the stump holes 600mm deep and 300mm wide with the posts 1500mm x 1200mm apart. The deck height above the ground will range from 300mm to 500mm and the span will be 8m x 5.5m. Is the stump depth and spacing sufficient for the 'H class' soil?

gday r kenny,

what size & type of timber are your posts, bearers, joists & decking? your footing plan seems sufficient, possibly excessive.

r's brynk

Hey, thanks for the reply. I will probably be using the following materials:
Stumps 90 x 90 treated pine
Bearers 90 x 70 treated pine
Joists 90 x 45 treated pine.
The deck will roughly be 8m x 6m.

R Kenny

Are you putting a roof over the deck. If so it may not be adequate. I would really suggest you get an engineers recommendation.

When we built sheds if a footing was 450mm Dia x 1500mm deep on normal soil on class H soil they jumped to 600mm dia x 2000mm deep.