How to lay a concrete slab – Easy as ABC

There are lots of reasons and uses to have a concrete slab in your garden.  In this case it is for a permanent, outdoor gazebo to rest on.  Check below for my detailed instructions.

Step 1

Firstly, score deeply the edge of the designated area with a spade, cutting down into the grass. The depth you need to excavate should be a minimum of 7 Inches to allow 4 inches for your concrete slab and a further 3 inches for the hardcore bottom.  Then commence digging your area, ensuring once done, it is level.

It is recommended that you find out what the frost level is in your area as frost can easily damage the slab. Depending on where you live you may have to dig deeper due to local weather extremities.

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Step 2

Now it’s time to build the frame that your slab is going to fill.  Place wooden pegs into the ground and carefully nail your boards to your pegs.  If you’re building a large concrete slab it is advisable to build it in sections.  This makes it more manageable when it comes to the steps below.

If you’re building a large concrete slab it is advisable to build it in sections.  This makes it more manageable when it comes to the steps below.

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Step 3

Lay a 3 inch layer of crushed stone, hardcore base and in the bottom of the formwork and spread it out evenly.

You will then ideally need to roll it down or use a wacker plate to compact it.

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Step 4

Pour concrete into the first area of your concrete base section.  Then use a screed board in a short sharp chopping motion, ideally with a friend the opposite side.

using a screed board

 

Once the area has been leveled it is time to smooth the area by rubbing the screed board flat to the frame and make forwards and backward motions towards each other.

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Step 5

 

The next stage is to smoothen your concrete out.  You will need to use a float to smooth out the surface.  You may notice that when using the float it will draw water out of the concrete, it’s nothing to worry about

floats for smoothing concrete out

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Last step

You will need to cover it up.  Just use some plastic to cover but ensure that if it does rain that it doesn’t sag onto your concrete.  Another reason to cover is to prevent animals from walking on it.

dog in wet concrete