Large Concrete Planters wall Thickness

[ReeceT]

Hi,

We are looking to landscape the garden and part of this is to have some planters up the side, the designer has spec'd sleepers then painted dark grey, the wife does not want sleepers and instead would like concrete planters as these can be smooth sided and 'fit in' with the rest of the design.

Each planter would be in the region of 3m long, 1m wide and around 60cm tall (this can be smaller if the walls end up being too thick). Whilst I am happy to cast any width concrete I would usually go overboard and make what is essentially a nuclear bunker.

Could someone let me know what sort of thickness I should use for the walls of the planter?

Thanks

Reece

 

[23vc]

Are you sure she’d prefer the look of bubbles on the cast concrete? Not to everyone’s taste and not to be confused with a rendered finish (although obviously much tougher)
In terms of your question I’d have thought 4 inches upwards would be good, but can’t say I’ve ever done a planter that way

 

[ReeceT]

I think they would have to be rendered to some extent, although I presume this could lead to blowing in the future. Is there a way to minimise the bubbles to achieve a 'smooth' finish...

 

[23vc]

Fwiw I’ve done this before in blockwork and rendered it, worked fine and looked good but there’s a general view that it’s not great for uk climate. But if you’re going to render, why not do it in block work
Re. reducing bubbles, good question, don’t know the answer

 

[^woody^]

3m of concrete is likely to crack, rendered or not.

Anyway, bubbles are prevented by having extra sand in the mix and vibration.

Made as panels, flat in moulds and reinforced, and well vibrated, 50-70mm would be feasible. But then you have the logistics of making several moulds and storing them for a good while for the panels to cure, and then being able to move them afterwards.

 

[tomfe]

I think these would look quire nice especially if you throw in some colour or some nice aggregate and grind in a finish.
Cast in sections and add movement joints.
Remove the formwork while green and trowel a finish.
You could use a textured form. Make sure you oil them first.