Building a raised bed / seating area

[dresbo]

Hi, I'm new here, so please bear with me, because I might be off the mark.

I've searched the forums but can't find exactly what I want

I want to build two raised beds, one about 60 cm high and one about 1m high, so that you can build some seating against it and use it as a back rest. Each is a relatively small area, about 2x3m for the taller and 2x1.5m for the shorter. They're more to separate the areas of the garden than to retain large amounts of earth.

I want to create a clean mediterranean look, so was hoping to use concrete blocks and rendering them. I know I need to ensure correct drainage and line the inside to prevent water seepage.

The soil is heavy clay. I have already dug and filled foundations around 350x200mm for the smaller wall and I hope this is large enough given the small amount of soil in the bed. For the taller wall I am a little wary. Do they need to be bigger than this and do I need reinforcement of some sort? Are heavyweight concrete blocks suitable and what size should I use?

Any advice gratefully received.

 

[noseall]

If the planters are a continuous wall, i.e. forming a rectangle, square, circle, etc, then they with be inherently strong by design. I would still use 7n dense concrete blocks (two skins) forming a 225mm thick wall.

Same applies to the foundations regarding the planter shape. The wall is less likely to tip or rotate on its foundations if the planter is continuous, so footings need only be say 200mm thick with the width being say 150mm wider than the wall itself.

Depth of found's will depend upon soil conditions, but it is fair to say that if you have reached virgin clay, then the conditions are unlikely to change whether you are at 450mm or 1000mm.

 

[dresbo]

If the planters are a continuous wall, i.e. forming a rectangle, square, circle, etc, then they with be inherently strong by design. I would still use 7n dense concrete blocks (two skins) forming a 225mm thick wall.

Same applies to the foundations regarding the planter shape. The wall is less likely to tip or rotate on its foundations if the planter is continuous, so footings need only be say 200mm thick with the width being say 150mm wider than the wall itself.

Depth of found's will depend upon soil conditions, but it is fair to say that if you have reached virgin clay, then the conditions are unlikely to change whether you are at 450mm or 1000mm.

Thanks for the reply! You're correct in saying that the planter is completely enclosed and I can see how that would give it more strength. I will take your advice and lay double thickness 7n blocks. I'll also make sure that the foundations for the taller are well into the clay just in case.