Will my very thin brick piers do the job?

[Nixolus]

Hi all.
I have an existing stone (rubble filled ) and cement wall, about 800mm high with piers at 1000mm. I want to extend the piers a further 1000mm and attach timbers on each side to fix horizontal timber board to (Probably Merbau decking boards). The wall is very solid and has been there for at least 50 years.

The problem is that the piers are slightly irregular dimensions, from 300 to 320 wide and 220 to 230 deep. I was going to try to build the brick extensions in a 1.5 x 1 brick layout, but I think on some pillars it will stick out a little.

Plan B is to drill a hole about 300mm into the stone pier and insert a 10mm reinforcing bar (1300 long), then lay the pier extensions 2 bricks each level. There wont be much vertical weight as the timber on each side of the piers will rest on the wall also, but I wonder if it is safe to assume that the rebar in the centre, along with timber bolted to the side will make the piers strong enough not to fall forward or lean forward.

I might mention that being not adverse to overkill, I plan to use ties on each brick, each level as well.

I haven't knocked up a drawing yet but let me know if it's needed.

To be very clear (as my colleague totally misunderstood what I meant when I asked his opinion). I am not talking about piers 2 bricks long each face. I am talking about piers with the dimensions of a single brick each face. 2 brick on each level.

Oh, and how long should I let them sit before I start drilling into them and fixing the timber?

[Nixolus]

I am going to go with sandstone blocks cut to size at vast expense. thanks anyway.