building raised planter bed

[Tony_A]

 

 

 

Hi there,

looking to build a raised planter bed. Probably 2 courses of Besser blocks. Was going to use the 90mm wide blocks due to narrow space when reaching the fence as we have some storm drains running parallel to it. Couple of questions with this, would I need any kind of damp course with this as some of the block work will be underground (my land runs slightly back towards house) 

and what kind of footing would it need? Would 200mm reinforced footing be ok for just 2 courses?

thanks. 

[JacobZ]

Hi @Tony_A,

Thank you for your question about installing a raised planter bed at your property. 

It's good to see you're thinking through your project, but you might be overthinking a little. I do the same, trust me, but what you're planning is fairly simple.

With two courses of blocks, adding a damp course will only protect a single course of blocks from rising damp. As the structure is being used as a garden bed, water will be present, so there is no real need.

For your footing, a 200mm reinforced footing is not really necessary. Reinforced foundations are important when there is a significant load being applied downwards, but in this situation, there's no weight pushing down on the blocks.

I'd suggest using the method shown in How to prepare a footing for a Retaining Wall from our supplier Adbri Masonry. This method allows more natural drainage than a concrete footing, which is ideal in a garden bed.

Use road base and compact it with a tamper or plate compactor. You can then use mortar to set the blocks in place and build up your wall. Once built, core-fill the blocks with either concrete or stones.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob