My low profile deck project

[propeller_plane]

G'day folks! 

Long time listener, first time caller. I'm writing here to see if anyone was willing to give their 2c worth with my upcoming deck project. 

My previously existing deck was pretty poorly built by the previous homeowner I bought my house from. I've since almost totally demolished it all (Just waiting to hire a skip bin this week) and looking to start completely from scratch. 

I have drafted the design for the deck, which measures 4800mmX5600mm. It's on relatively low profile on sandy soft ground so I'll prop it up with TuffBlocks, thought I just thought I'd share my design here and see if it looks kocher. I have ensured to have 450mm spacing between joists, 1800mm spacing between bearers below that. Joists and Bearers I'll be using H3 Treated Pine 45mmX190mm, and the decking itself will be Merbau (140mm wide), bearers will sit on the TuffBlocks. 

This is what I've drafted up on a Deck designer I got linked to off the TuffBlocks website, what do you all reckon? What would be the best screws/nails for this job as well? 

Thanks all 

The deck will butt up to the rear doorway and tiles and the decking will be level and flush with itSite of the new deckSite of the new deckThe proposed design

[Jason]

Heya @propeller_plane,

Great to have you make your first post. We're excited about seeing your deck project come to fruition. Let me tag some very experienced members in @Adam_W, @Brad, @ProjectPete, @royq  and @gippslandhome who might like to share their opinions on your plans and materials. 

Please don't hesitate to post anytime you need a hand, or let me know if you ever need help getting the most from the site. 

Thanks,

Jason

[Brad]

I have found these useful

Irwin Quick-Grip Deck Tool Kit 

If you want hidden screws?

Camo Hidden Deck Screw Guide 

Kreg Deck Jig - The one I use. 

Some people also paint the top of the joists black so they are more or less hidden from view between the gaps.

[ProjectPete]

Looks like you've made a great start @propeller_plane 

• Your joists don't have to go on top of bearers, you can attach to the side of them with joist hangers instead. This saves you some digging/clearance below the deck as you need 300mm between sand/ground and the underside of your deck for airflow to avoid residual moisture damaging your timber.
• You can use 140x45 for your bearers and 120x45 for your joists - sufficient sizing and will save you $$$. Just recalculate your bearer spacing based on smaller profile timber to make sure sufficient but off the top of my head, 1800mm should be fine.
• 400mm centres on your joists is ideal but 450mm is OK.
• I've heard mixed results on Camo/hidden screws over time so I haven't used them on my own decking and mention this to customers when they want them and they can make their decision. Camo/hidden fixings are great on a composite deck, as they stay dimensionally stable besides the end to end expansion and contraction. Timber however has the tendency to move around. Given this, some chippies won't install using any method of fixing that isn’t your standard top fix screw. The force of the fixing pulling the board down from the top is much more effective and fool proof than a side angle fix. I'm not specifically recommending against them - just saying. I'm a fan of Wurth SS decking screws given their strength and self-drilling features as well as their aesthetically pleasing small Torx head.
• Predrill holes for screws where you're joining boards (ie. 4 screws in joist) to make sure you don't split the ends of your boards. 
• Definitely paint the top of your joists black and go down each side about 40mm. It gives you a cleaner finish. Not painting will definitely show the pine against your dark Merbau decking.
• Getting consistent spacing between boards and even/consistent screw positioning is made easy with a 'deckhand'.

Hope this helps - really looking forward to seeing what you end up with. Love building decks!

[propeller_plane]

G'day @ProjectPete 

Many thanks for your valuable advice! 

As for the Decking screws, I was going to go down the Kreg decking screws path as part of their Deck Jig system: https://www.carbatec.com.au/kreg-deck-jig-system

And to join the timbers with the Joist hangars, what do you reckon, screws or nails for those, or do I need to use both? 

Thanks again! 

[propeller_plane]

Thanks @Brad for your advice! I was going to go down the road of using the Kreg Deck jig. 

[ProjectPete]

No worries at all @propeller_plane 

Just use decking nails for the hangers.

[propeller_plane]

Hi folks! Me again... I'm just trying to pick the right fasteners.... 

To fasten the ledger board (45mm thick H3 Treated Pine) to the concrete part infront of the back door (Refer to photos in first post), I was going to go with Ramset Ankascrews. As for assembling the bearers to each other, 16 Gauge Buildex 100mm long Construction screws. These sound pretty close? 

Thanks! 

[ProjectPete]

Go with the 125mm version of these - easy to work with and strong fixing. Suggest 400mm spacing - just make sure they don't interfere with your joist positioning.

Those screws for the bearers will be fine although maybe a bit too long. Do make sure they're made for treated pine as the chemicals deteriorate standard screws. Screw the bearers together from both sides for ultimate strength. Even pop a bit of extreme strength liquid nails between them.

Consider the positioning of your screws holding the frame together to ensure they don't interfere with where your screws for fixing the decking to the frame are going to go.