How to pour concrete between drain and pavers?

Question

Hi I am looking to insert a small bit of concrete between an outdoor drain and oavers, exactly like what is circled in yellow in the picture.

Could you advise steps needed to insert a bit of concrete like this? How do you hold the concrete in place?

If you could recommend a product to use that would be great, preferably similar to the one in the photo which has blue specs in the concrete.

JacobZ · Answer

Hi @Lozd0g,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

When pouring concrete, generally you would build a formwork out of timber, which is anchored into the ground to prevent movement under the weight of the concrete being poured. You can have a look at an example in How To Build Formwork. In this situation, if you were backfilling a relatively small gap between a paver and a drain, then the weight of the concrete would not be enough that you really need to build anything, you'd just pour the concrete into the gap, then smooth and finish it. The paver and drain will hold the concrete in place.

Your starting point would be to clear out the gap to ensure it does not have things like sticks and leaves that can decay beneath the concrete causing voids, then add a small layer, around 25-50mm thick of a compactible material such as drainage gravel or road base, then compact it using a tool like a tamper, or in this situation where it is quite narrow, the head of a club hammer.

Once the base is prepared you would mix your concrete and pour it into the gap. Unfortunately, I am not aware of a product that uses that kind of decorative aggregate, which was likely a custom mix, however you could simply grab a bag of standard concrete, pour and smooth it out, then at the end drop in some blue stones and smooth it out so they are visible. They look like a type of aggregate that is often referred to as blue metal, or bluestone aggregate. It is available in bags in some areas, but not all, so you would have to check availability at your local store.

For further guidance, you can check out How To Pour A Small Concrete Slab which shows the steps for prepping, pouring and finishing a small concrete slab. Due to the size of your pour, there would be no need for steel, so you can ignore this part of the process.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

Lozd0g · Answer