You could either use Protectadeck, flashing, or isolate the timber from the brick. You'd isolate the timber by placing a few washers on the Dynabolts or screws before inserting them into the brick. Spacing the timber away from the bricks stops moisture from being trapped and encouraging rot.
I can't foresee an issue with drilling an extra hole in those brackets. Once again, you can use washers to raise the brackets if that allows you to use the original holes. A spacing of one meter between brackets on a 140mm bearer sounds about right.
With low-level decks, people are often trying to use the smallest timber possible with the least amount of mounting points. In your case, it sounds like you are well within span lengths, and it should be a substantial deck.
Please let me know if you have any questions.
Here's a bit of a progress update.
Have got the bearers in, and attached to the ground as well as the ledger attached to the brick, and spaced away from the brick with 2 x 3mm M12 flat square washers per anchor. Almost cooked my Bosch Professional Driver by putting the Anchor screws into the ground concrete, and I only did 1 beam at a time. There is definitely some crazy force required. The Bosch was spitting out oil towards the end of the 3rd bearer, so for the 4th bearer I opted to use a good old Craftright Ratchet set ... that was some really hard yakka with the short arm for leverage ... but it got it mostly done. And the bits I just couldn't do ... the driver sorted out!
I will be borrowing my neighbours Impact Wrench for the second bit of deck when I put the in, as I'm attaching the joists straight to the ground.
Measured out my square with reference to the door. I didn't get the level absolutely perfect as there is a slight drop on the ledger of about 3 or 4mm over a 6m span, so I was happy with that level of precision. I've measured the exact same slope on the suspended bearer, so at least they are equal.
You can see my patched brickwork on the bottom left where I hit the pipe!
Mounted the first set of angle brackets
And all attached. I used stringlines at 5 points (1 at each end, 1 in the middle, and 1 at the 25% and 75% points) to level it all out and remove any bowing from the wood. The beauty of running a bracket at every 1m rather than wide 2-3m spans is that you can bend the wood to remove the bowing rather than needing to plane it.
I haven't yet put the 2nd bolt into most the brackets, as I needed to drill the second hole anyway, because even if I had used washers to raise the brackets, there is approx 2cm of bolt head the wood is sitting over, meaning it wasn't low enough to get a good hold. But my cordless power drills (Bosch Professional) just don't have the oomph to quicklly drill through the 5mm galvanized steel. So went and bought a SDS chuck attachment for my Ozito SDS drill, and hopefully that will have the oomph with the carbon steel drill bit. Even if it isn't faster, at least I won't need to charge the battery every 3 holes!
Have also put down ome weed matting over the sand area along the house, don't want any weeds growing up through the deck. Will be putting down some drainage gravel over it to hold it in place with the pins. On the other side I'll be building a raised garden bed, so no need for weed matt there just yet.
Thanks for sharing your progress @Itai. Sounds like it's been quite a build with plenty of lessons learned along the way.
Look forward to following along with the rest of your project.
Are you able to check why the 140x19mm 5.7m Merbau isn't available anymore: https://www.bunnings.com.au/140-x-19mm-5-7m-merbau-pre-oiled-select-grade-fj-decking_p0177414
Is it a stock shortage, or is there another reason?
The deck I'm building is 6m long, and I was hoping to make the entire length with a single run of Merbau + perpendicular piece at either end to give me a total length of 5980.
Alternatively, I could potentially use this: https://www.bunnings.com.au/specrite-140-x-21mm-5-7m-pre-oiled-concealed-fix-decking_p0064519 but it's 2mm taller then the edge pieces would be, not sure if that would be noticeable. Can I still use these with normal screws, or would I have some setbacks or notice anything visually? If I were to use it concealed fixings, how do you do the end boards, because I can't seam to find boards that only have the groove on one side?
Edit: I've been reading the Ekodeck fastening guide here which seems to give me the answers I need to most of my questions about concealed fixings: https://www.ekodeck.com.au/media/1499/qf-6mm-timber-2020-web.pdf
If I were to rip the edge of the the concealed fix decking to make an edge, would I need to oil it again? And can you recommend a right size router bit to round the ripped edge so that it would be the same as if it were not ripped.
Also, can the concealed clips be used on top of Protectadeck flashing?
I'll reach out via PM to get your location details. I'd like to call the store to verify whether this product is no longer stocked there.
I don't believe the 2mm will be particularly noticeable, but to the discerning eye, it could be seen. Obviously, since you know about it, it'll stick out to you and might become a bugbear.
Thanks Mitch. All good, I've decided I want to go with the concealed decking system anyway, so I'll go for the concealed groove boards.
But will the concealed system work with the protectadeck? I assume it should?
@chuckyjr That's great to hear. They are very useful aren't they! I'm looking forward to getting the roof on mine up.