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concrete raised beds

Hi all

Newby to the forum here, hopefully someone can help me...   I have just bought a new house with a nice courtyard garden. It is about 80% sandstone paving, with a strip of gravel on the back edge, hemmed in by brick walls on two sides and a fence on the third. I would like to turn the strip of gravel into a contemporary raised bed, to plant some bamboo and an dwarf acer. I want the bed to be one of those white rendered affairs that are common in swanky roof gardens etc, dont judge me....

After research, the method i am going to take is:

Get rid of gravel, dig down and fill with compacted hardcore.

Mark out shape of raised bed and hammer in a rectangle of rebar, and wrap with some reinforcment meshing.

Build the shape of the raised bed in plywood forms, up against the paving, but leaving a couple of inches gap against the walls and fence.

Fill the lot with concrete, leaving the bottom part of the raised bed for drainage (so i have essentially build four walls in a rectangle shape).

Once dry, take off the forms and paint it with some kind of thick white waterproof paint to give a nice finish. 

I am also wanting to install a waterfeature like a water blade to trickle down into a part of it, i think i will build the structure for this out of plywood and paint it with the same thich waterproof paint so it looks like it is part of the concrete.

My questions are, will this work? Have i missed anything? Does anyone have a suggestion on the waterproof paint which will also blend in the concrete to the plywood water feature? 



  • Dave HumbyDave Humby Posts: 1,145

    Would it not be much easier to build it from blocks and have them rendered? Or am I missing something? Do you need to give consideration to drainage?

  • Dave HumbyDave Humby Posts: 1,145

    PS Welcome to the forum. 

    Last edited: 22 July 2016 09:22:09

  • smcdsmcd Posts: 9

    Yes it would no doubt be easier, but I am aiming to do this myself, and I am firstly nervous of building blockwork that might fall down when weight is against it, and also am not confident I could get a half decent finish in render without having to call some pros in. Whilst the reinforced concrete, whilst more time consuming and probably more expensive, will be whole lot more structurally sound.

    Will leaving the bottom un concreted give enough drainage or will it need something else? 

  • smcdsmcd Posts: 9
    Dave Humby says:

    PS Welcome to the forum. 

    Last edited: 22 July 2016 09:22:09

    See original post

     Thank you☺

  • smcdsmcd Posts: 9


    This is pretty much what i am after if it helps 

  • Dave HumbyDave Humby Posts: 1,145

    Very nice. If you're looking to achieve the very clean lines as in the image I think you will struggle to do that with a plyboard section for the water blade, if I understand your description of works correctly.

    As a minimum you will probably want to use marine ply due to it being outside. Regarding the water blade is the plan for the water to fall into the planting bed? I'm confused on that part lol.

    Regarding structure I think solid concrete is overkill but if you want to go down that route you could make the blade 'wall' in the same way using vertical rebar from the base wall. 

    Might be a good idea to have a chat with a builder on the options. 

  • smcdsmcd Posts: 9

    Right, for some reason i hadnt thought of using concrete for the blade wall.

    Intention is to have one section of the bed as stones over a mesh and container for the water to fall into, sorry, I missed that part out entirely! 

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