How to build a garden bed?

[Samc1234]

Hi, 

I am wanting to build a garden bed. I plan on creating a concrete footing of double the width of brick laid on top of crusher dust.  - What concrete can I use and how long to leave before laying bricks?

I am also wondering as the soil of clay, do I need to build a frame or can pour concrete into trench?

Thanks, 

Sam

[MitchellMc]

Welcome to the Bunnings Workshop community @Samc1234. It's amazing to have you join us, and many thanks for your question about creating a garden bed.

For your garden bed, you’ll want a solid concrete footing to support the brickwork. A standard concrete mix is suitable. The width should be double the brick width, and the depth should be around 100–150mm for a small wall, though deeper may be needed for taller beds.

While reinforcement isn’t essential for low walls, adding steel mesh or rebar can provide extra strength and durability. Once poured, allow the concrete to cure for at least 24–48 hours before light work, but it’s best to wait about 7 days before laying bricks to ensure sufficient strength. 

Since your soil is clay, you can usually pour directly into a trench, but using a simple frame can help keep the footing straight and level, especially if the trench edges aren’t stable.

Here's a helpful guide: How to pour a concrete slab.

Please let me know if you have any questions.

Mitchell
 

[Samc1234]

I am wanting to build another brick garden bed. It is approximately 80cm, wide. Currently my understanding is that I:

1. dig trench

2. put 5cm of crusher dust compacted

3. put 10 cm of concrete for footing

4. lay bricks insuring weeper holes

However, if I am going approx. 8 bricks high, do I need to use an reinforcement or should just building it with mortar be ok?

[JacobZ]

Hi @Samc1234,

Assuming you are using standard house bricks, which are 76mm in height, adding 10mm or so for mortar, your garden bed will be around 650-700mm high.

You're approaching the height where reinforcement would be wise, and adding some Jack 70mm x 46m Galvanised Brick Mesh into a couple of the mortar lines is an easy way to do this.

Outside of this, the approach you have mentioned looks sound. I am excited to see what you come up with.

Jacob

[Samc1234]

Thanks Jacob, 

So I do not need any steel rods?

How high can I go with using just the brick mesh?

[JacobZ]

Hi @Samc1234,

Due to the way each course of bricks is offset by half, you can't really run steel rods up a brick wall. Besser blocks, on the other hand, due to the cell in the centre, can be reinforced with steel rods.

When you say bricks, are you referring to house bricks or besser blocks?

If it were besser blocks, then adding vertical reinforcing would be easy. If it is house bricks, there isn't really a simple way you could do this, and we'd have to look at the specific design to propose a more robust method of reinforcement.

If you were close to 1m in height, we would have to look at how we could install additional reinforcement, but being below this, you should be fine with just brick mesh.

Jacob