Hi I am looking to build a deck 6m x 6m it will be over a exposed concrete footpath as well as paving. I only have 130mm of height to build with as I was hoping to build over the concrete and pavers . I was looking get advice on footings and timber for sub structure type of timber sizes and centres. I'm open to all options and opinions I'm looking at using spotted gum decking 136mm x 19mm .