Merbau decking over concrete

preechish

Hi, hope you're all doing well.

I'm planning to build a 7.2m long ×  4.2m wide 160mm high deck in my backyard over the alfresco which is going to extend all the way to the fence. The dirt area will be levelled with crushed rock and a thin layer of concrete to flush it with the existing concrete floor. 

It would be great if someone can guide me through the installation process like how much gap should be there in between floor and the timber base. What is the best bracket to use which is going to hold the deck sturdy. 

MitchellMc

Welcome to the Bunnings Workshop community @preechish. It's great to have you join us and many thanks for your questions.

I'd encourage you to start with the guide: How to build a low-level deck by @Adam_W. I trust it will answer most of your questions. There are also many previous discussions on this topic which you should find useful. These can be found through the search bar under "low-level deck".

You'll need at least 10mm of clearance underneath your joists for air-flow and drainage. You can pack out under them with shims to establish this gap. Dynabolting the joists down with brackets every meter will secure them to the slab.

Do you know how much room you have to work within? This is measured from the slab to the doorsill. If you can let me know this measurement, I can work out some appropriately sized timbers to use.

Mitchell