How to build a limestone planter box and bench?

[JamesAndrew]

 Hi team, 

I'm looking to build similar to this limestone block planter box and bench seat. 

Blocks used with be 500mm x 350mm x 200mm reconstituted limestone. 

I have built similar before in the same block size on compacted sand, with the first course approx 200mm under ground and it's had no issues for over a year. 

My question is regarding footings. 

I have seen companies lay on compacted yellow sand at ground level. 

I have also seen people use compacted cracker dust as a footing. 

My preference would be a 300mm wide x 100mm deep reinforced concrete strip footing, however I am wondering if this is overkill? 

Any advice is greatly welcome. 

Thanks

[EricL]

Hello @JamesAndrew, 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your limestone planter box project.

I'm a big fan of over-engineering and using a reinforced concrete strip does not sound over the top to me. It's an excellent way to provide that extra level of stability to your planter box project. If you have the time to build it, I'm putting my vote to it.

Let me call on our experienced members @Dave-1, @Nailbag and @AlanM52 for their recommendations. 

If you need further assistance, please let us know.

Eric

[Nailbag]

Hi @JamesAndrew 

I think the type of soil you have to begin with plays a large part in what your footing options are. The deeper and softer ground needs deeper more solid base and then there is clay-based which has the added potential; on-going issue of movement.

With this build, I would agree with @EricL and stick to concrete footings. It's going to be a guaranteed long term structurally sound base especially when building any brick/block wall.

Nailbag

[Dave-1]

Good morning @JamesAndrew 

Id go straight for a concrete footing, I have bessa block retaining walls (only two high) that failed dismally as soon as a section was broken. They were sitting on compacted ground with no footing. Have a look at the first couple of steps in this project Large gabion retaining wall 

It shows why I am not keen on no foundation for that type of wall. So concrete footing plus drainage. I dont think your footing is oversized, its pretty much the size id go for.

Dave

[AlanM52]

Hi @JamesAndrew,

I would also go with the concrete thing.

Cheers