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Hi,
I am thinking of DIY crazy paving an existing patch of concrete in our backyard. My main concern is a large crack that runs through the middle, maybe a tree root or settlement? Not recent. About 20-30mm difference at the highest point. Can I use compacted road base as a substrate above this concrete slab to provide an level even base for the crazy paving?
Hello @dididi
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about doing crazy paving in your backyard.
Crazy paving needs to be anchored to the concrete surface with adhesive, it will not work with compacted road base as the road base is to loose to anchor onto. Instead of using road base, I suggest using Lanko 20kg 173 Floor Leveller or Sikafloor Level 30 (special order product). These floor levellers are rated for outdoor use and can go on between 25mm up to 30mm in thickness.
Before you place the floor leveller on, I suggest giving the surface of the concrete a good clean with 30 Seconds 5L Outdoor Cleaner Concentrate in combination with Oates Long Handle Deck Scrub Brush. If you have access to a power washer, I suggest using it to rinse the surface of your concrete base. Make sure that the surface is totally dry before you use the floor leveller. Please make sure to follow the application instructions so that it anchors correctly to the concrete base.
My best advice is to give the floor leveller enough time to cure before you start paving the surface. Please keep in mind that the floor leveller will level the floor area, but it will not compensate for any future movement.
Here is a handy step-by-step guide: How to lay crazy paving
I suggest having a quick look at these discussions:
- Crazy paving for backyard fire pit by @EleventhCoastal
- Crazy paving front porch by @EleventhCoastal
- Crazy paving outdoor entertainment area by @marissa4
- Alfresco makeover with crazy paving by @jesseydiamond
- Crazy paving for outdoor living area by @ElissaC
Please remember to wear personal protection such as gloves, goggles and a mask when working on your project.
If you need further assistance, please let us know.
Eric
Hi @dididi,
That area looks quite large, roughly three and a half metres by ten metres, which would make it a very big project for crazy paving. Even when the base is solid, crazy paving takes a lot of time because you need to break the pavers, find pieces that fit together and trim them to shape. A square metre of regular paving might take half an hour to lay, but crazy paving can take up to three hours per square metre once you factor in all the fitting and adhesive work. For a space this size, that would be a huge amount of time and effort.
There’s also the issue of that cracked slab. A 20–30mm height difference suggests the ground has moved or roots are pushing up from below. While you can use a levelling compound to even the surface as Eric mentioned, that won’t prevent more movement in future. If the slab shifts again, cracks will show through the new surface and could cause the paving to lift or break.
You might like to consider some alternatives that are more practical and still improve the look of the area:
- Painting: Once the surface is cleaned and levelled, applying a quality concrete paving paint is a simple and effective way to freshen it up. There are plenty of colours available to complement your outdoor space, and you can use a textured roller to add grip and prevent slipping.
- Outdoor rugs and furniture zones: Breaking the space into smaller zones with outdoor rugs, potted plants and furniture can disguise imperfections and create inviting areas for relaxing or entertaining.
- Gravel or stone overlay: You could edge off parts of the concrete and cover them with decorative gravel or pebbles over a weed mat. This softens the look of the hard surface and adds some visual interest.
- Decking pavers or a low-level deck: Interlocking decking tiles are another option. They can be placed directly over stable concrete to give the appearance of timber decking without needing to build a full frame. Alternatively, you could build a small, low-level deck over part of the area to create a feature zone and reduce the amount of surface you need to treat.
If you’re really set on doing crazy paving, it’s worth testing it on a smaller section first to get a sense of the time involved and to see how well it holds up before committing to the full space.
Here's an AI-generated image to give you some ideas.
Please let me know if you have any questions.
Mitchell
