DIY Doctor UK DIY Forums

I’m building two raised planters. Their height will be about 500mm above ground level. 600-650mm in total.

one of the planters is 1.8m wide and the other is 5m wide. Both are 1.1m deep (front to back).

im using concrete blocks, laid on a concrete footing which is 400mm thick. The soil underneath is light clay.

Will single skin be strong enough? Or do I need to make them double thickness?

Hi dmoblay
At 600mm high a 100mm thick wall will not survive more than a few years. Suggest you use 150mm thick blocks and form a double thickness internal pier at the centre of the 5m planter.
Regards S

Thanks for the reply. What about the 1.8m one? Will that be ok?

Hi dmoblay
Still suggest you go for 150mm but you could try 100mm and if it cracks in a few years rebuild it.
Regards S