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Can You Put Slabs On Uneven Ground? (How To)

Putting in a concrete slab proves easiest on level ground, but not every yard starts out level. Your yard may feature small variations in ground slope. The smaller the slab, the easier this becomes to work around.

You’ll need to do some work to even out the ground, because while you can create a concrete path on uneven ground, you can’t lay a slab on it without making changes to it.

To put a slab of concrete on uneven ground might require you to first dig and fill the ground to level the surface. You’ll then need to frame the area of the slab so the concrete mixture can fill the form and dry in the shape needed.

Concrete slab preparation

The ground can start out uneven but needs leveling to hold a slab. Use a level to measure the site’s pad vertically and horizontally. The term pad refers to the square or rectangular area measured and marked off in which you’ll pour the concrete. Typically, you remove all grass and lay an even layer of sand. You mark off the area, dig it out, then pack it down to level it.

Should You Put Slabs on Uneven Ground?

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The yard a slab goes in can have as uneven ground as you can imagine. The area of the slab must get evened out though before pouring concrete.

You should not put concrete slabs on uneven ground. Doing so would result in a sloped patio with more concrete flowing into the downslope and too thin an area on the upslope.

You might end up with a smooth top by over pouring, but the thin areas will chip quickly. You don’t have to even the whole yard, just the area that will hold the concrete.

What Tools Do You Need to Put Slabs on Uneven Ground?

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When you need to dig out the yard, then pack it down and frame it, you need three sets of tools. These tools comprise essential items that most homeowners own. It does require some shopping for materials. You’ll need to order them online from an e-tailer or make a trip to the local hardware supply.

It is not recommended to put slabs on uneven ground. But if you choose to do so anyway, the tools you will need include a shovel, level, and tamper. The project will also require sand, gravel, or another base, low-slump concrete, support frames of steel, or another hearty material, and lumber.

What Preparations Do You Need to Install Slabs on Uneven Ground?

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The three steps to prepare uneven ground for a concrete slab require about two days of work. Setting aside a weekend provides ample time for digging and tamping, also called compacting.

In preparation for installing slabs on uneven ground, measure the width and length of the area you plan on filling and mark each side using stakes and string. Dig out the area to a depth of about two inches. Any higher areas, dig out until they remain level with the other, lower areas. Tamp the ground.

Measure one side of the square or rectangle of the slab first, staking it at one end, then unrolling the string until you reach the far corner of the side.

Check the string’s straightness with a level. Insert the second stake to create corner number two and tie the string onto it.

Double-check the straightness with a level and make any necessary corrections.

Repeat this process to finish your square or rectangle.

Step inside your stringed area and start digging with a shovel. This slow, arduous process creates the necessary tiny patch of perfectly level ground in an otherwise hilly area.

Dig from corner to corner, working backward from your starting point until you reach the rear of the pad site.

Step over the strings and finish the digging process. The area should resemble a mostly level patch of ground.

Grab your tamper and begin working backward from one corner to the other by section. You will probably find it easiest to start from where you finished digging.

Tamp the ground soundly until it all becomes level within the stringed area.

You finish when the site remains flat and measuring it with a level shows it all measures the same. This may take some time and require serious force with the tamper.

Copyright article owner is for this article. This post was first published on September 15, 2022.

Add the sand or gravel needed and smooth it out. It also must spread out evenly. Create a completely level surface.

How to Install Slabs on Uneven Ground?

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You probably just want to pour the concrete in a form on your ground immediately, but that won’t work well. You must prepare your ground first.

To install slabs on uneven ground, you will need to first prepare the concrete mix. Construct the form inside the dug-out edges of the stringed-off pad site. Place your two-by-fours flush against the pad site edges and attach them. Mix and pour the concrete, then smooth it. Allow it to dry.

Determine how much concrete the project requires. Because you dug out to an even depth all around (unlike digging a swimming pool), you only have one calculation. With a sloped project, you have two. Multiply the length times the width times the depth.

Using two-by-fours, construct the frame, also called the form. Your form holds the wet concrete in place. Without it, it sloshes around and seeps into the edges of the ground. With this firm form in place, the wet concrete molds to it.

Mix the concrete unless you purchased pre-mix. Pour the concrete quickly but evenly into the form. This typically requires one or two other individuals to help spread the concrete mix quickly and evenly. Low slump concrete pours well and stays in place once poured and leveled.

Once dry, you remove the frame and fill in some of the excavated dirt around it to make everything look nice. For this reason, keep the dirt you excavate from the yard to create the pretty pad site. It comes in handy for the fill-in dirt.

Alternate method: Use paving slabs to create a quick patio or other outdoor space. You will still need to pour concrete between the slabs to keep them together. If you use slabs, tamping and compacting the ground until it becomes even, and level takes on a higher priority.

Using slabs creates seams and seams when unfinished create a trip and fall risk. Use spacers to create the tiny space between your slabs as you lay them in your pad site. Start in one corner. Lay a slab. Insert at least two spacers. Lay another slab. Repeat the process, moving across the pad site until you reach its far side.

Insert two spacers along the bottom end of the slab you start from, then lay a slab to begin creating your second row of slabs. Lay spacers, then slabs until you reach the other side of the pad site again. Repeat this process until you fill the entire pad site with slabs and spacers.

You may now mix and pour your concrete. The spacers you inserted ensure that you create an even space between each paving slab or stone. Slabs do make the work go quicker but they add a step that you would not have if you chose to lay concrete and smooth it out. Either method results in a flat patio or another concrete area in an otherwise uneven yard.

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ReadyToDIY is the owner of this article. This post was published on September 15, 2022.

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