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Hi All,
We are currently planning to build our ecodeck over an existing concrete slab under the alfresco. We dont have much experience however we are willing to learn as we go and take inputs from you all. I have seen quite a number of posts and decided well we can do it ourselves too 
To start with the dimensions of our alfresco is 3.1m*3.6m. there is a 149mm stepdown from the living area. it can be seen in the attachments.
My questions are twofold:
1. is with regards to the sub structure
2. one is with regards to the ecodeck itself.
I will start of with my questions in relation to the sub structure as I want to get this one before I lay my Eco deck.
Question 1: How do i get the 149mm height of the deck to the brick face?
My 2 cents: using brackets which will be dynabolted to the ground along with 20mm packers OR use a combination of 90x45(bearers) along with 70*45 (joists) and packers- (45(bearer) +70(joist)+10?
Question 2:
spacing the joists at 450mm apart is what i plan to do. However I have often seen that towards the face of the wall some people use 2 joists and add small noggins between them? is that so that they can picture frame the deck easily?
If I were to follow a similar process how do i attach the joist next to the brick wall?
Your response would be really appreciated.
Thanks
J
Hello @ssjolly
Welcome to the Bunnings Workshop community. Thank you for joining us and sharing your question about Ekodeck on a concrete slab and the picture framing method on a deck.
It's great that you've decided to plan out your deck! If you were to use the Treated Pine Outdoor Timber Framing 70 x 45mm plus the Ekodeck Decking you would have a total of 93mm. This would leave you with a gap of 56mm, using bigger timber would make that gap even less. However, if you are using the Carinya 75 x 50 x 20 x 4mm Galvanised Angle Bracket - 4 Pack, I recommend using the Treated Pine Outdoor Timber Framing 90 x 45mm so that the brackets will work in combination with your packers.
Would it be possible for you to draw your plan and post it? This will give our members a better idea of your framing and provide you with a comprehensive recommendation. The common practice when attaching your deck to the house is by installing a ledger. However, it all depends on how you plan on laying your frame. Please keep us updated, we look forward to seeing your decking plan.
Eric
Hi Eric,
Thank you for the valuable inputs. I have attached plan of my sub structure below. I have highlighted a few questions below:
In addtion to the above, with regards to the 149mm drop. I plan to use 90*45 treated pine, 75 x 50 x 20 x 4mm galvanized angle bracket , a 20mm shim. This would still give me 137mm(which is 90mm+4mm for Bracket+20mm Shim+23mm decking). I am still short about 12mm to get it flush to the level of the brick. is there a better way to address this?
With regards to the shims or packers, do they need to be sandwiched between the angle bracket and the concrete?
Thanks
J
Hi @ssjolly,
It's great to see @EricL has been assisting you.
I'd suggest you use Dunnings 80 x 80 x 40 x 5mm M12 Galvanised Angle Bracket and fit your 90mm timber to them at your required height. These brackets are significantly more rigid than those you have chosen and will allow you to alleviate the timber higher. You don't need to use both holes to fix the timber, just one. Alternative the sides you place the bracket on to give the joists rigidity. You'll want the joist to finish at 126mm high, as when you add your Ekodeck, it will be flush with the sill. Just pack out under the joist 36mm or thereabouts. Two Macsim 15 x 72 x 100mm Grey Shims and one Macsim Fasteners 72 x 100 x 5mm Yellow Half Shim will get you close enough.
Alternatively, you could use the Builders Edge 25-40mm Pedestal Foot Minifoot, which will make your life super easy. If a fall is graded into this area to drain water, the adjustable feet are perfect for counteracting it.
The deck doesn't need to be attached to the wall as long as you can use brackets into the concrete. You only attach to the wall if you can't attach to the ground.
Please let me know if you have questions.
Mitchell
Hi @MitchellMc ,
Thank you so much for your feedback. This gives me the confidence to go ahead and start purchasing the timber and other products.
What you have said makes complete sense and I am happy to go with either of the 2 methods. When it comes to the strength of the Sub Structure which one of the above methods would you recommend?
Method 1: If i go ahead with the first method of using angle brackets and packers, How many sets of packers(Two Macsim 15 x 72 x 100mm Grey Shims and one Macsim Fasteners 72 x 100 x 5mm Yellow Half Shim) would i need along the joist. Once I have screwed/bolted the joists should I remove the packers or leave it there?
Secondly, with regards to the screws/bolts- which ones would I need to attach the joist to the bracket and which size dynabolts would i need to attach the brackets to the ground?
Attaching the joists along the timber- Do we need to use pryda joist hangers on either end of the joists?
Method 2: If I were to go ahead with the alternative method:
Would I need to use the brackets for my outer perimeter (for the joists along the walls and the outside border? it can be seen from the picture below:
Do I use dynabolt to fix the base plate of the Builders Edge 25-40mm Pedestal Foot Minifoot?
Thank you once again for your suggestions. I really appreciate it
Every 600mm for the brackets would be a fairly safe bet. You could likely stretch it out a bit further, and you can check out timber span tables online if you wish to minimise supports. If you use an adequate amount of L brackets, you don't actually need the packers. I'd advise alternating the side you place the bracket on down the length of the joist. That way, the joist is not just supported on one side. You would only really need maybe 3 stacks of packers under each joist. One at either end and one in the middle, and you can leave them there.
Zenith M10 x 40mm Hot Dipped Galvanised Hex Head Coach Screw would be fine for connecting the bracket to the joists and Ramset 12 x 70mm DynaBolt Plus Hex Nut Bolt for into the ground.
You likely won't fit the pedestal feet if the border is hard up against the wall, and brackets can be used instead. You might be able to fit the feet if you space the border slightly away from the wall. The feet do not need to be fixed down on the concrete.
Mitchell
Hi @MitchellMc ,
thank you once again for your inputs.
With regards to the brackets itself, for Dunnings 80 x 80 x 40 x 5mm M12 Galvanised Angle Bracket- do I need to use 1 dynabolt or you would recommend 2(one in each hole?)
If 1 dynabolt is more than enough, can i use Dunnings 40 x 80 x 40 x 5mm M12 Galvanised Angle Bracket instead of Dunnings 80 x 80 x 40 x 5mm M12 Galvanised Angle Bracket-?
As far as the timber sub structure is concerned, do you recommend Protectadeck 45mm x 50m Flexible PVC Joist to nail over the structure before i put my deck boards?
Thank you for your help
Regards
Jolly
One Dynabolt will be fine on your alternate bracket, @ssjolly.
Adding Protectadeck 45mm x 50m Flexible PVC over your joists before the decking will certainly add to its lifespan and is a great way of stopping water pooling on the surface of the them. If the alfresco roof is open and the deck will receive direct rain, I'd certainly recommend adding it.
Mitchell
