How Many Blocks Do I Need To Build A Shed

How Many Blocks Do I Need To Build A Shed

DIY shed building has grown in popularity in recent years. Not only are people becoming more self-sufficient, but it can save you a lot of money. Paying service fees for installation can substantially add to the cost.

Building your own shed is a relatively easy to learn process. Start at the bottom and work your way up. How many blocks do you need to build a shed? I’ll help you work out the math.

How Many Blocks Do I Need To Build A Shed

To build a shed, you will need 20 to 60 blocks for the foundation, depending on the size of your shed. If your shed is on unlevel ground, you will need more blocks to stabilize it. If you are building a 6ft x 8ft or smaller shed, concrete blocks are not required as long as the ground is level.

How Do You Calculate The Number Of Blocks For Shed

To calculate the number of blocks for your shed, you need to measure the shed. Typically, sheds are either the same on all four sides or two long and two short sides. For this process, we will work along the front side to create rows.

You need one block in every corner. Starting with the spot where one of the front two corners will be, place a block.

You will need to place another block every twelve to forty-eight inches across the front until you reach the other corner. These will be directly under your floor joists when you build.

Once you have a block every twelve inches, you know how many rows you have. Now you need to look at the depth of your shed, the side measurement.

Blocks along the same floor joist should be a maximum of 72” apart. The spacing between blocks on different floor joists should be a maximum of 48” apart.”

Now that you know how many rows and the number of blocks per row, the math is easier than you think. Multiply the number of rows by the number of blocks in the rows, and that’s how many you need for a level surface.

How Many Concrete Blocks Do I Need For Shed Foundation

The number of concrete blocks you need for your shed’s foundation depends on its size, weight, dimension, and even the ground beneath the shed.

It is okay to place concrete blocks six to eight feet apart along the rows as concrete is incredibly durable and can handle massive amounts of compressive pressure.

The framing materials also affect the number of bricks you need. It’s always better to plan ahead and do a little more than you think you need than to do too little and end up having a costly accident.

Plus, you can get hurt if the floor falls out from underneath you while you’re inside. Even falling a few inches through splintered wood can result in a broken ankle.

The chart below has a rough estimate of how many blocks you need for 14 of the most common shed sizes.

However, you should always check with your local ordinances to find out if there are additional requirements. No one wants to build a shed only to find they have to tear it down and redo the base later.

Shed Dimensions

Number of Blocks

6ft x 6ft


8ft x 6ft


8ft x 8ft


8ft x 10ft


8ft x 12ft


10ft x 10ft


10ft x 12ft


10ft x 16ft


12ft x 12ft


12ft x 16ft


12ft x 20ft


12ft x 24ft


16ft x 20ft


16ft x 24ft


How Many Blocks Do I Need Calculator

You can follow a couple of different formulas for spacing your blocks. However, so long as you use at least the minimum, you can add as many blocks as you need.

Moreover, you may require more than the minimum, depending on the ground and how high you plan to elevate your shed.

First measure along the front of your shed. Take the number of feet and multiply by twelve to get the number of inches across.

Next, you want to divide that number by forty-eight, the maximum distance you should place floor joists and support blocks apart.

If you already know how far apart you’re placing those floor joists, then divide by that number of inches instead.

You will get a small number, usually between two and ten. This is your number of rows. Please write this number down, so you don’t forget it.

Next, measure along the side. You don’t need to multiply this number by anything since you’ll be placing blocks four to six feet apart. All you need to do is divide by four to six feet. Write that number down as well.

You can adjust slightly here to get the best support and ensure that you have blocks underneath the shed if it’s a smaller size.

For example, you don’t want to skip putting blocks under the center of a six-by-six elevated shed, so it’s okay to add blocks only three feet apart.

Regardless of the adaptation, multiply the two numbers you wrote down to get the total number of blocks you need.

If you plan to raise your shed two blocks high, or you want better floor support so you can store heavy items inside, then you can multiply your total by another 1.5 to 2.

This will give you one and a half to two times as many blocks to work with.

Simple Method

Multiply the two side lengths (in feet) together. Take that number and divide it by four. That will get your number of rows for blocks spaced forty-eight inches (four feet) apart.

This is the quick and simple method for finding how many blocks when you need them four feet apart evenly.

If you want twice as many rows, which means rows only two feet apart, multiply your total by two. This method works best on sheds with sides that are multiples of six, such as six by six, twelve by twelve, and twelve by twenty-four.

How Many Breeze Blocks Do I Need To Build A Shed

Breeze blocks are cinder blocks with two holes in the center. These are preferred for some uses because they are light weight yet sturdy. Moreover, breeze blocks make a superb shed floor if you aren’t using another floor.

Breeze blocks are sixteen inches long by eight inches wide. To get your breeze block floor measurement, you still need to measure your shed’s side dimensions.

Multiply the number of feet on each side together, and then multiply by twelve to get a square inch measurement.

Don’t be alarmed by the large number; divide it by forty-eight, which is the number of square inches on the solid face of a breeze block.

The total is the number of breeze blocks you need.

How Many Concrete Blocks Do I Need To Build A Shed

Concrete or cement clocks are typically used in small stacks called piers. These towers are often two to three blocks which and they are spaced three to five feet apart.

So the math here is pretty simple. Start by multiplying your two side measurements together (in feet) as always.

Take your total, that’s your square footage and multiply it by the number of blocks in each pier, which should be either two or three.

Then divide this by three, four, or five depending on how far apart in feet you want the piers (stacks of blocks) to be spaced from each other.

The total is how many blocks you need.

Helpful Tips To Know About The Amount Of Blocks Needed To Build A Shed

The way you support or build your shed floor will influence how many blocks you need. Fortunately, the math is fairly simple for any of these processes.

Here are more helpful tips to know about the amount of blocks you need to build a shed.

  • Always get more blocks than you need. Whether you are looking to build a breeze block floor and you need t to extend wider than the shed walls, or you accidentally drop and break a block or two in transit, it would be best to have extras.
  • Sometimes you should not use blocks under your shed. For example, if you plan to park a car or other heavy equipment inside the shed, you need a gravel or cement pad beneath it for safety reasons.
  • Leveling your blocks is crucial to a well-built shed. Even an inch or two of tilt will put a massive strain on the walls of a prebuilt shed. Alternately, if you are building from scratch, unlevel blocks will mess with all your measurements.

Final Thoughts

Building your own shed is a very rewarding process. However, it can go bad quickly if you don’t level the area and make sure to raise the shed off the ground.

Using blocks to lift and level is a smart plan because pouring concrete is much more complicated and requires drying time, but blocks are ready-made and easy to work with.

Now that you understand how to calculate the number of blocks you need, you’ll have your shed up in no time.

Drew Thomas

My name is Drew Thomas and I’m the creator of Fun In the Yard, your one stop site for all your outdoor games, sports, party activities, outdoor gear, and lawn & gardening tips.

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