How to lay bricks for raised flower bed?

Hello @Brunnie_Rich

Welcome to the Bunnings Workshop community. Thank you so much for joining us and sharing your question about laying bricks for a raised flower bed.

If you are stacking the bricks more than four high you will have to build a concrete slab for it. Soil compaction is also a factor when laying bricks without a cement base. However, if the flower bed is going to be very long and you will be putting in more than a cubic meter of soil, I suggest going with your first choice letter (A). Using rebar to support the cement base will prevent it from cracking under the weight of the soil. Please remember to give the cement slab enough time to cure before you put anything on top of it.

I recommend leaving a gap of 100mm between your flower bed and the fence. The gap will allow you to service the fence in case it needs repair. It sounds like a fantastic project for your garden. Any updates you can post while building your raised brick flower bed would be much appreciated.

Here is a link to a handy guide: D.I.Y. brick planter box

Let me tag our experienced members @tom_builds and @ProjectPete for their recommendations.

If you need further assistance, please let us know.

Eric

tom_builds

Hi @Brunnie_Rich and thanks for the tag @EricL

@Brunnie_Rich rather than laying a full concrete slab under the entire flower bed area I would suggest considering pouring a strip foundation that is twice the width of the bricks you intend to use around the edge of the bed. You can then build the wall on top of this foundation.

Doing it this way you will save on a heap of concreting work, and won't need as much reinforcing steel either. Water inside the flower bed will also be able to drain into the soil below, reducing the need to design drainage.

Looks like you've got a great project underway, I'm interested to see how it goes!

Best of luck,

Tom

https://www.workshop.bunnings.com.au/discussion/comment/16608#Comment_16608

Hi @EricL , @tom_builds ,

Thank you so much for your replies and suggestions, really appreciated - it's so good to get some informed views on this.

I've only just joined this community, but loving it already!

I do like the idea of less concrete - would the same depth of 4 inches be sufficient for this approach too?
And, would that mean adding soil back to the middle section to pour, or creating an inner frame, and then back filling once set?

Also, there's a little caveat that I didn't mention previously, that may or may not change your view - I would like to put some sort of seating in the far corner (and eventually continue another bed along the adjacent brick wall at the end of the pic there. Would this change any approach?
So to describe that further, the bed wall runs along the length of fence, soil section is partitioned just past the extra bed dug on the right, then some sort of wooden seating is used either across the top, or possibly recessed a little to accomodate wooden bench seat. (still planning this)

If all goes well, I'll definitely update this thread with the progress 🙂

Thanks again,
Rich

https://www.workshop.bunnings.com.au/discussion/comment/70887#Comment_70887

Hi @Brunnie_Rich

Thanks for updating us with the details of your plan. I've drawn up a quick sketch of your raised garden bed with seating based on @tom_builds recommendation of an open cement foundation. Please have a look and tell us what you think. Just to give you an approximation 4 inches is about 100mm +. Please note that the sizes indicated are for reference only, please adjust them to your needs.

Please keep us updated with your progress. We look forward to seeing your raised garden bed with seating assembled.

If you need more advice or information, please let us know.

Eric

Brunnie raised garden with seating1.jpg

tom_builds

https://www.workshop.bunnings.com.au/discussion/comment/70887#Comment_70887

Hi again @Brunnie_Rich,

For pouring the foundation I would create a box inside a box like in the diagram below and then pour your concrete into the space between them. You will need to stake the frames, on the corners and along the width of the outside of the outer frame and the same on the inside of the inner frame to stop the frames from moving when pouring the concrete.

For foundation thickness 100mm is solid, although to build the frame you will probably find 90mm timber easier to get your hands on and for the purpose of a garden bed a 90mm foundation will be fine.

For the seat following something along the lines of @EricL's drawing is a good idea, that way you can either build a wooden or brick framed seat area. A strip foundation works best when load bearing walls run directly over it, which will likely be the set up of your seating area so no need to approach that area differently to the garden beds.

Feel free to follow up with any other questions that arise while you're completing this project.

Tom

https://www.workshop.bunnings.com.au/discussion/comment/98632#Comment_98632

Hi @EricL ,

Thanks for the diagrams, really helpful!
My one question at the moment would be whether this would be advisable to use gravel underneath the concrete, or if it's ok to lay the concrete directly on top of the soil. (The soil is pretty well compacted)

https://www.workshop.bunnings.com.au/discussion/comment/98634#Comment_98634

Hi @tom_builds ,

Thanks for this diagram and advice - using less concrete would be preferable so this sounds like a good direction, I think I'll use this method.
This is a long(ish) term project for me but I'll update this thread with the progress and I'll certainly be back asking a few questions along the way.

One extra question I've thought about whilst typing, is about the height of my bricks and the stability of retaining the soil.

I'm looking to recycle bricks reclaimed from the previous use (see attached pic). They're half sized bricks (in height, but the footprint is the same as regular house brick) and I intended to go about 8 high max (measuring 40cm, then adding 1cm of mortar in between would make it approx 48cm high total)

Is this height ok in terms of stability? Eg. could there be too much stress from soil volume to crack the walls (i'll also be looking to render these and paint white)?

I was envisaging laying bricks in a single line in the usual manner.

CC @EricL

https://www.workshop.bunnings.com.au/discussion/comment/116084#Comment_116084

Hi Brunnie_Rich,

It's recommended to place a bed of road base or crusher dust 6-7cm thick, rake it to a level surface and tamp it down firmly all over to a thickness of 5cm. This provides a stable surface for the slab. If you don't compact the ground with road base, you'll definitely need reinforcement mesh and will probably see at least hairline cracks in the slab/foundation.

At 48cm high, I don't believe you'd experience any issues with stability, but @tom_builds might like to give his thoughts as well.

I'll be looking forward to following along with your project. Keep us updated.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/126029#Comment_126029

Hi @MitchellMc ,

Thanks for the extra advice, very much appreciated.

I was hoping to use bar in the concrete and lay the concrete on the compacted soil - if you think I should lay road base/crusher dust and it's a must do, please let me know. I'm tackling this job on my own at the moment, so looking to minimise the effort with any heavy bags of materials needed!

I've uploaded a sketched model of what I intend to be building in the space. I'm hoping to complete the seating area independently of the raised beds either side, so would be laying those concrete foundations separately over time. Screen Shot 2021-11-16 at 11.54.35 am.png

https://www.workshop.bunnings.com.au/discussion/comment/132685#Comment_132685

Hi @Brunnie_Rich,

It's one of those things where you really should be compacting the ground. All good solid concrete foundations are built upon compacted bases. Your soil might be adequately compacted, but it's almost impossible for us to be able to know. My only thoughts are that once you build the garden beds, it would be a shame if an area subsided and for all your hard work to be ruined. At the very least, I'd encourage you to hire a compactor for a few hours and go over the soil with it.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/136767#Comment_136767

Hi @MitchellMc ,

Ok, thanks for the advice, you're right, it would be a shame for the hard work to go to waste should anything subside!
I'll look to add in a layer of what you recommended before the concrete and compact. Thanks again for the advice, very much appreciated.

https://www.workshop.bunnings.com.au/discussion/comment/16608#Comment_16608

Hi @EricL @MitchellMc

Happy new year 🙂

I promised an update, and have attached the progress so far.

I've another one or two layers of brick to add, and then will bead and render. For the concrete breeze blocks (the grey ones), would they need rendering inside the bed, to protect from any soil/moisture leaching through and affecting the outside render?

Btw, I have made some mistakes along the way (with the slab sizing), but used a fair bit of bar in there, so hopefully it'll be ok in the long run!

Thanks,
Rich

https://www.workshop.bunnings.com.au/discussion/comment/71505#Comment_71505

Hi @Brunnie_Rich

Thank you so much for the photo updates. You've made fantastic progress and it's looking very good.

Please keep us updated with your progress, we look forward to the grand reveal when it's all put together.

Eric

https://www.workshop.bunnings.com.au/discussion/comment/71505#Comment_71505

Hi @Brunnie_Rich,

That's looking great!

Rendering the inside won't prevent water from seeping through the breeze blocks. Render is cement-based, just like the blocks. If you want to stop water transferring through, you can apply Crommelin Exterior Grade Brushable Waterproofer on the inside. This will assist with preventing water staining on the render. Apart from the aesthetical discolouration of the render, I don't believe the moisture transferring through the wall will damage it. Render breathes and should allow the water to transpire through it quite quickly. If you use paint or a sealer on the exterior render, you'll need to waterproof the inside wall. Otherwise, the water pressure will blow the render off the wall.

Please keep us updated and reach out if you need further assistance.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/99042#Comment_99042

Thanks @MitchellMc ,

That's really great info to know, I'm glad you told me that!
I am planning to paint the render after, so will need to use that waterproofer on the inside then.
I'll keep you posted on the progress, and thanks again for all of the feedback so far, this is a great community and source of advice.

cc @EricL @tom_builds

https://www.workshop.bunnings.com.au/discussion/comment/116314#Comment_116314

Hi @MitchellMc @EricL @tom_builds ,

I finally got my bench set in place and thought I'd share the end result. I'm pleased with the result overall and now need to get some plants in there.

I do have some small hairline cracking where the seat sits directly on top of the beading - I may repair this in future. I think it's where the beading may not have been adequately stuck to the brick work as it appeared before the seat was placed, but the additional pressure may increase this over time. Not a big deal for me currently! There's also some run off from the timber stain, this I'm hoping will stop after a few rains. And, in one of the photo's you'll see some solar lighting wires coming from the tree - these aren't cracks in the render, just temporarily hanging there for now!

Thank you al for your advice, really helpful and made this project a lot less stressful, thanks 🙂

I do have one further question for advice - drainage around the foot of the planter - what would be the best way to allow water to flow around this?

https://www.workshop.bunnings.com.au/discussion/comment/127008#Comment_127008

Hello @Brunnie_Rich

I suggest looking at either Agi drains or Everhard Easy drains. Both products will require you to dig a channel in order to install them. Plus you'll also need to consider where they will drain out to. From a design point of view, you can accessorize the top of the agi drain with pebbles so that it will look nice, unfortunately, the Easy Drain will need to be left open so that nothing obstructs the flow of water into the channel.

Let me call on our experienced members @Jewelleryrescue and @homeinmelbourne for their recommendations.

If you need further assistance, please let us know.

Eric

Jason

Great job on the bench seat @Brunnie_Rich. It looks fantastic and I'm sure will inspire many other Workshop community members.

Jason

Jewelleryrescue

https://www.workshop.bunnings.com.au/discussion/comment/24869#Comment_24869

Hi @Brunnie_Rich Nice brick work and I also use pavers as brick work capping stones 🙂

Re your water drainage question: Unless your ground is becoming a soggy mess I wouldnt be to concerned if it rains and some water is trapped againt the wall i am assuming. I have brick work it traps water for a short while next day it is gone. I do have an ag drain through the wall but is it worth the effort drilling some holes through yet . One day if i get bored as I am working other projects currently

Plan A slightly raise soil level in the trapped water zone so a tiny slope 1:20 allows water to flow to the ends of the brick work.

Plan B dig a small trench 100x 100mm deep along the front fill with graval and sand take it to the ends of the wall. As @EricL says a ag pipe is the ultimate if you have serious pooling water but ag pipe would be 150mm down by the time you top cover it with gravel and it need to go some where or let the water bubble up at a blind end once it past brick work. You can always extend it at need. If you get floods best to take into storm water pipe back towards your house so your neighbours arnt impacted by concentrated water flows. Grass will grow across trench.

I hope your water issue is slight 🙂

Re your garden If you mulch it on top Suger can or Whoflungdun after dig a few worm s up and slip the under the compost and the soil the worms came from too in case there is worm castings they will help transport and fast track a lively earthy eco system.

petriwhite

https://www.workshop.bunnings.com.au/discussion/comment/71505#Comment_71505

Hi @Brunnie_Rich, awesome project and thanks for posting the updates through here.

I'm looking to build something very similar myself - keen to hear how much rebar you put into the strip footing and where/how your placed it? did you opt for mesh, or just rebar rods running through the structure? If you used rods, did you place them through the centre depth of the slab or nearer the bottom? Any tips would be great!

Thanks, Pete

Jason

https://www.workshop.bunnings.com.au/discussion/comment/103620#Comment_103620

Hi Pete (@petriwhite)

Great to see you've been inspired by @Brunnie_Rich's project. Hopefully they will be able to come back to you soon regarding your questions. I'm sure our resident Bunnings D.I.Y. expert @EricL would also be happy to assist as soon as possible. Feel free to share more details about your project and post as many questions as you wish.

You might also to check out our Top 10 most popular raised garden bed projects shared by other community members.

Welcome to Bunnings Workshop.

Jason

Jewelleryrescue

https://www.workshop.bunnings.com.au/discussion/comment/103620#Comment_103620

Hi @petriwhite

The best steel for you to use is Trench mesh Reo

Jack 1800 x 200mm Light Duty Reinforcing Trench MeshI/N: 1060367

$22.85

It is reo bars welded together to make concrete extra strong under load.The reo mesh is 200mm wide great for a brick wall. basically the function of the steel is even if the ground moves under the weight of concrete and bricks and cracks there is no drama as the steel locks it all together. Raise the steel middle way in the cement to rust proof it and gives cement maximum support, Lift the steel with any thing like bits of rock or broken brick or buy reo stools/chairs (plastic spacers designed to lift steel up into the concrete.

Do line the trench with plastic as it makes concrete when poured a smooth shape which adds strength as a uniform shape. Use any plastic laided flat.

I notice in the picture cement path on end and a brick wall the other end. This is where reo bar come into play I would drill with a rotary hammer drill, holes to insert 300mm lengths of reo bar into the holes to act as pins to the existing concrete and wall footing this will hold you new footing at the wall and path level even if the ground sinks a bit.

Have you ever cursed council foot paths sunken in spots and raised in others they should have pinned into each new slab and used expansion joints.

Expansion joints foam every 5 to 10 meters and between old and new work you may not need it.

https://www.workshop.bunnings.com.au/discussion/comment/103620#Comment_103620

Hello @petriwhite

While we are waiting for @Brunnie_Rich to confirm the size of the Reo bar, would it be possible for you to show how big of a footing you are planning to build? If you are building a narrow footing, then I suggest using Australian Handyman Supplies 12mm x 2m Reinforcing Round Bar in combination with Jack 25 - 40mm Plastic Reinforcing Bar Chair.

I propose having the reo close to the center mass of the footing to provide maximum support. My best advice is to make sure to use WD40 on the frame as a release agent for the formwork.

If you have any other questions we can help with, please let us know.

Eric

https://www.workshop.bunnings.com.au/discussion/comment/103620#Comment_103620

Hi @petriwhite ,

Thanks for asking, hopefully sharing my experience will help.

I did use some bar in there, nothing too heavy duty. Looking back at the pic, I can see I used a slightly thicker bar around the edge, and slightly thinner in the middle. It was for a brick planter, and has worked out well.
Top tip for the rebar is to make sure you place it on some stones, to raise the height of it to ensure it sits in the middle of the concrete (vertically). That way it won't sit on the floor/bottom of concrete, and weaken the overall slab. I also used wire to mesh the off cut bar together, to hold it in place when pouring the concrete in - this is also a must I'd say.

Other tips -
- Mix the concrete well - not too wet (weakens it), not too dry (won't pour) - Youtube was my friend for this as you'll get a sense of the correct consistency.
- Make sure you use a sufficient thickness of wooden frame (pic shows a good thickness). My first slab I skimped and used a thinner frame - I found I needed to quickly add more pegs to brace it as it bowed after pouring the concrete. I got away with it, but made it more stressful for a first time effort.
- I used a canola oil spray (cheap and worked) on the inside of my wooden frame before pouring, where it came in to contact with the concrete. Made it easy to remove the frame after the concrete had set.

I made this slab over a year ago now, all is good and solid!

Good luck with your project 🙂

petriwhite

https://www.workshop.bunnings.com.au/discussion/comment/118873#Comment_118873

Thanks Eric. We are planning to build quite a long series of raised beds against our fenceline.

The beds will be built from 10 series concrete block, with a similar style render finish to @Brunnie_Rich‘s project.

We have a ~30m fenceline, and are planning to build the beds along ~20m of this. The beds will be ~80cm width (ie two standard blocks), and will be three courses of block high (~60cm). Each bed section will be ~1.8m long (ie four standard blocks and 2x dividing walls)
We have dug the trench (~25cm wide) for the footing for the back line of the beds (couple of photos attached pre-and post-road base), and have laid a layer of compacted road base to sit the concrete footing on. Do either you or @Jewelleryrescue have any recommendations for the concrete footing depth (we were planning 12cm, with rebar at mid-height), and whether both the sides and base of the trench should be lined with plastic or just the base. We are planning to pour the concrete footing in sections (either 1 or 2 bed sections at a time, ie 1.8 / 3.6m sections), with expansion joints between each. Do you have any recommendations for expansion joint foam, and/or is it possible to fill with the road base instead?

many thanks - really appreciate the advice so far.
pete

Jewelleryrescue

https://www.workshop.bunnings.com.au/discussion/comment/127985#Comment_127985

Hi @petriwhite

Hi am a bit confused with your plans. If you are going to build a bed 80cm wide with bricks all round i think i am reading for you desired results where is the foundations for the 80cm width? I would highly recommend digging and pouring each section or two sections as you plan including the sides and front footings at the same time so the footing is done and ready to go in one pour.

As it looks now you are starting with one long back wall so that makes footings weaker if you try join into the back wall with the side footing later. But I might have miss understood your planning so sorry if I have. Your plans for expantion joint are good use expansion foam every 2 sections is plenty.

Consolidated Alloys 125mm x 10mm x 25mt Roll Foam Expansion Joint I/N: 1060549 $35

Expantion foam has a bunch of home uses for the extra you will have.

As you prepare footings for one or two bays have steel protruding out down your 20 meter brick line 30to 40cm long lengths and push your expansion foam onto the steel to create an expansin joint ( Foam.) but at the same time tie the footings together so they move as one if they linked and move together.

I prefer 250mm deep minimum for three bricks high but you all ready dug 12cm and filled it with road base. But you might be able to compensate with a very strong concrete mix . Plants are powerfull and there roots can crack footings and lift and twist them with ease, Maybe you neighbours plants?

I have a tree and it grew from sappling 25 years later, now its root lifted my extra think footings of 300 mm square up by 40mm but the brickes are as good as I layed them as an example. A weak footing would have ripped apart bending the steel trashing the wall needing rebuild.

No road base is required for concreting your better of mixing it in with the cement and pour it in to a deeper footing. Ie your planned 120mm plus your road base depth =? lets say 50mm so final cement footing is 170mm thick. Is better and stronger.

I am just about to build a 2 besser brick raised garden bed with capping I will dig all the footing, line it with plastic (Smooth concrete is stronger by shape and more impervious to water.) lay trench mesh and lift it with concrete stools or brick chunks mine will be 250 x 300 deep my choice there (general cement mix) set the form work to parellel at correct height and pour. The whole footing ready for bricks.

No release agent is ever needed in DIY projects a simple tap to the wood will pop it off after a week of drying. If you try to release footing to soon concrete can be damaged while green maybe thats how the release myth started. or Oil it if you want