How to build a brick garden bed on concrete?

[felipenm]

Hi there!

I want to do a DIY project for a small garden bed where a small part of the wall will sit on concrete and the rest of the wall on dirt. The reason for having part of it on dirt is for drainage. Otherwise I’d build everything on concrete. 

See the photos of where I want to build it and another one where I’m drawing inspiration from. 

I’m thinking of using bricks and then rendering it to paint it in white. I will use gravel and ag pipe for drainage. Wha am I missing? Or should I use different materials?

Thanks in advance. 

Regards

Felipe

 

 

[JacobZ]

Hi @felipenm,

Thank you for your post and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

This sounds like a fantastic project that you've already done some great planning for. Having the planter box half on the concrete and half off is a great idea for utilising the space while still allowing the garden bed to be free draining.

The materials you have chosen are perfect and I'm sure they will create a fantastic planter box.

One suggestion I have, assuming the planter box would sit up against the house, is using Bastion 4L Exterior Waterproof Membrane to prevent water from flowing under the brick and render on the house side of the planter box. This should be painted on the ground and up the wall to at least 300mm.

Once you've done this, you can build the planter box, and paint the inside of the planter box with the same membrane, using Crommelin Waterproofing Tape at the bottom corners of the planter box, where it sits on the concrete. This will essentially create a waterproof skin that will only allow the water to drain where you want it to. 

Another suggestion I can add, is to line the inside of the planter with geotextile membrane to prevent the garden soil from eroding down between the gravel and to prevent any weeds from growing up through the gravel side of the planter box.

Let me know what you think and if you need any further advice.

Jacob

[felipenm]

Hi Jacob,

Thanks for your response.

A few other questions:

• The half off the concrete (on dirt) will be around 50cm high. Do I need a concrete footing for that part of the planter box? Or can I lay mortar straight on the dirt and bricklaying on that?
• Do you recommend a mortar product or the products that should be used to be mixed up to create the mortar for bricklaying?
• As for the render, I have a bag of MR 75 Mansory (Render Systems) sitting around. Is it a suitable product to render the bricks once they have been laid down and the planter box done?
• Any other suggestion in terms of products to use?

I believe the overall steps would be as below. have I got it right?

• Measurements done
• Clean the area
• Make sure that the ground is leveled (dirt side)
• Apply Bastion 4L Exterior Waterproof Membrane on the ground and up the wall 
• If concrete footing is needed, then build a concrete footing, otherwise start with mortar
• Then start laying the bricks down always checking the level
• After the planter box is done, paint the inside with Bastion 4L Exterior Waterproof Membrane
• Then use the Waterproofing tape at the bottom corners on the concrete
• Render the inside and the outside of the planter box
• Paint it in white, mostly the external side
• Then line the inside with geotextile membrane
• Then put an ag pipe sitting on the space created between the concrete and the external wall of the planter box
• Then garden soil, plants and pebbles 

Regards

Felipe

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[felipenm]

One more thing, do I need to worry about termites? If yes, I would need to get a termite barrier applied I would expect.

[JacobZ]

Hi @felipenm,

A concrete footing would certainly be worthwhile on the side that sits off the concrete as it will give you a good solid foundation that water will not erode, so your garden bed will not shift. You might like to have a look at How To Dig a Foundation and How To Mix Concrete for a bit of guidance.

Ready-mix mortar products are much easier than mixing sand and cement and unless you were buying in bulk, which is not necessary for this sized project, the difference in cost is minuscule. 

As long as the render mix you have is still in good condition, it should be fine.

There's no real need to worry about termites as you are not changing the structure of the house and termites won't eat any of the materials you are using.

The steps you've written out look good, but I would suggest you start by measuring and marking out the area, then excavating down around 100mm so you can add the gravel and ag pipe before everything else.  Then pour a concrete footing, apply the waterproofing and then follow the rest of your steps.

It sounds like you've got a good handle on things and are going to produce a great product.

Keep us in the loop if you need any further assistance along the way and don't forget to share the end product. 

I'm excited to see what you come up with.

Jacob

[felipenm]

Hi Jacob,

Thank you. Your help is much appreciated. I will let you know how it goes.

Regards

Felipe

[JacobZ]

Hi @felipenm,

I can't wait to see the end result, I'm sure it will look absolutely fantastic.

You might also like to have a look through Top 10 most popular planter box projects, Top 10 most popular raised garden beds and How to fill a raised garden bed for some additional advice and inspiration you can use once the garden bed is complete.

Jacob