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Is a 12×12 Shed Going to Work for You?

A 12×12 shed is a good size for people who have a large yard and are going to need storage for more than a push mower and a few long-handled tools. It can easily hold a riding mower without you having to squeeze around it to get to anything else in the shed. If you have a small yard, and only need perhaps a battery-powered push mower, you probably won’t need that much space, unless you have some large toys, such as ATVs, jet skis or snowmobiles.

Most folks can make use of a 12×12 shed, it is large enough to store most items and still have some room to do some small projects in.

Plan out those must-haves you want to store and draw out your items using ballpark measurements before you decide on a shed size. You may see that you need either a larger shed than you thought or that you can make do with a smaller one, such as an 8×10. Keep in mind that over the years, people tend to buy more things that need to go into a shed, not cut down. It never hurts to have a little extra room.

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What Can Fit in a 12×12 Shed?

A 12×12 shed can hold quite a bit, even the larger stuff. You can store lawn mowers, whether riding or push, wheelbarrows or yard wagons, ATVs, bicycles, snow blowers, and any of the smaller power or hand tools.

The best way to make use of your space is to plan out where you want to park the larger equipment before putting in any shelving. That way, you won’t have any awkward moments bumping your head against a shelf any time you put away that lawn tractor.

If you have a lot of long-handled tools, you might want to try a hanging rack to save space. Try using graph paper and drawing out your plans to help you see just what will fit where and how much space they will leave. There are all kinds of ways to make use of that space.

How Much Would a 12×12 Shed Cost to Build?

Of course, the larger the shed, the more the materials will cost. Floor space is not the only criterion. The height of the roof will play into the cost, and so will extras such as windows, or a double door instead of a single door.

Even planking the ceiling rafters for more storage space will add some cost. The type of materials will also greatly affect the cost. A small vinyl shed will cost far less in materials than a metal shed, or one built entirely of wood.

There are other considerations as well. If you need a building permit for a shed, and you probably will with a 12×12 shed, there is the cost of the permit as well as extra sets of plans to submit for the permit. The land clearing and leveling can cost an extra $1,300 to $4,400. The foundation itself costs extra, especially if you plan to have a concrete slab foundation.

A slab can run between $4,000 and $12,000, depending on the size and the local market. This is something you need to check on when you apply for a building permit, as some areas will require certain types of foundations or limit your choices to a short list. If you want other things such as electricity, plumbing, or insulation, the bill goes up.

If you want a custom-built shed instead of a pre-fabricated one, and you can’t do the building yourself, count on adding $10 to $20 per square foot for having a pro build one from a kit and $40 to $75 per square foot for having one built from raw materials.

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All in all, building a shed plus materials will cost around $60 to $150 per square foot, so a 12×12 foot shed will run $8,640 to $21,600, depending on materials costs. As far as the time involved, it will probably take a couple of pros about eight hours to build a 10×10 shed from a kit. Add in the foundation or custom plans built from scratch, and you could be looking at a period as long as two weeks, especially if some materials deliveries or the concrete people get backed up.

How Do You Build a 12×12 Shed Foundation?

The first thing to consider is the site where you plan to put your shed. The ground should be as level as possible to start to limit the amount of leveling work you have to do. It should also be as solid as possible to prevent shifting or erosion. Soil problems can cause your shed to eventually start tilting or sinking. Of course, you can put a shed on a slope, but this should be avoided, if possible, to limit rain runoff and the inevitable ground erosion it causes.

There are several types of foundations, but some of the most popular are the concrete slab, gravel base and concrete piers with brackets set into the concrete to hold the wooden frame. The concrete pier base is the best if you need to build on a slope. Posts are set into brackets atop the piers. This allows for some posts to be longer than others to counteract the slope.

The concrete slab will need at least four inches of gravel underneath to carry away water. The gravel should be poured and spread two inches of depth at a time, then tamped firmly down to keep the gravel from shifting. Tamping two inches of gravel at a time is much easier and gives better results than pouring a deeper depth of gravel before tamping. The concrete itself should be at least four inches in thickness.

Gravel bases are very popular. This involves virtually the same start as the gravel for a slab. The shed is then usually placed skids or on deck or pier blocks, which have either brackets already set in them or have slots to hold your skids.

Concrete piers are good for sloping yards and those in northern climates which require that the piers be set at least a foot below the frost line to keep them from moving or cracking as the ground shifts during freezing and thawing. They can be formed by the homeowner using concrete mix.

You may want to rent a small mixer for this. The holes are usually dug with a post-hole digger or augur, averaging four feet deep. Allow an extra six inches or so for tamped gravel below the concrete.

The piers themselves are poured using SonoTubes. These are coated cardboard tubes made just for this type of job. Use tubes about three times the diameter of your post widths. Cut the tubes as long as the holes plus six inches so that part of the concrete piers sticks up above ground. The piers are usually spaced about eight to ten feet apart.

If you’re unsure about how many you’ll need, it’s better to have too many than not enough to ensure the stability of your shed. Once your piers have started to dry, set in your brackets on top of each.

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One good tip to keep rainwater away from your shed is to extend your gravel base out at least a foot all the way around. This will catch rain running from the roof and lead it away from the shed. It will also prevent this runoff from eventually digging a ditch alongside your shed on either side. For more information on more types of foundations read my article What’s the Best Shed Foundation for You?

What Kind of Roof is Best for a 12×12 Shed?

Most people opt for a gable roof. This allows for extra air space to help funnel out excess heat, and also provides a little more storage space if you cover the ceiling rafters. You can easily install air vents into the gable ends to provide airflow even when the shed is closed up. You also won’t have the worries of rain possibly collecting as it will on a flat roof. Usually, for a 12×12 shed, the middle post will be around 36-1/2 inches long.

Another type that keeps the rain off is the single-sloped type that slants from the high side of the shed to the low side. You only usually have rain runoff along one side of the shed.

As far as your roofing materials, the most popular are asphalt shingles with an underlayment. The underlayment will prevent leaks should a shingle be cracked or torn by falling debris. This type is also less expensive than some other types such as metal. Many people will use the same color shingles as the ones on their houses. Of course, there are several choices as to roofing materials. See what your preferences and budget will allow. Get more information in my article The 7 Most Popular & Practical Shed Roof Designs.

How to Layout Doors and Windows in a 12×12 Shed

Your main door should be on a short side that allows easy access. For instance, if you build on a slope, you won’t want to put your door on the land’s high side, as rainwater will invariably try to run right into your shed. On the other hand, if the shed is on a noticeable slope, putting it on the low side may present its own problems.

You may need to put the door on one of the sides instead of the front or back. While this doesn’t seem like much of a problem, having the door on the long side may limit “parking” space a bit for your larger equipment, such as lawn tractors and the like.

If your shed is large enough, you can have more than one door. Many people choose to have a door on both a short end and a long side. One may be a double door set up for ease in getting that large lawn tractor through and a single door elsewhere for just ducking in and grabbing a tool.

If you only plan to have one window, it should be on the opposite side of the shed from the door to encourage airflow through the shed when the door and window are open. After a rainy day or during very humid days, it’s a good idea to air out the shed to prevent moisture from accumulating on the inside of the shed and on your equipment and tools.

Don’t forget the importance of keeping air flowing through your shed as much as possible. Working people don’t have the luxury of leaving the shed open to air all day except on weekends. Good attic ventilation will help a lot. You won’t have to worry about the shed getting too hot or moisture accumulating inside to cause mold or mildew or rust on your tools.

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There are many styles of attic ventilation. If you have a pitched or gable roof, building in or adding gable vents on either end keep the air moving inside when the shed is closed up. Others are simple roof vents that have raised covers to keep out the rain, but allow the hot air to rise up and out. One good type is the turbine vent. Hot air will rise through the turbine fins, causing the turbine to spin. This pulls hotter air up and out.

If you’re building your shed, it’s fairly easy to add any of these vents into your plans, but they certainly can be added later if needed. For instance, suppose you bought a house with a pre-existing shed that has a concrete slab used as the floor. You have no way of knowing whether the previous owner put a moisture barrier underneath the slab.

You will find out once you find that the shed floor is damp much of the time and your stored items start to show signs of mildew. This is where adding ventilation comes in.

Is a 12×12 Too Big to Move?

That depends on what kind of shape the shed is in and how well it was built. You’ll need to do some prying up, so the shed needs to be able to hold its shape without deforming or breaking apart.

Also, there’s a big difference between moving it to another part of the yard and moving it across town. After all, it’s not the kind of shed you can fit into the back of your pickup. If you need to move it any distance, you’ll probably need to hire professional movers.

If you’re just moving it to a new site in your yard, however, you can move it with a couple of friends and some sturdy piping or logs to use as rollers. Put some diagonal bracing across door and window frames to help support them during the move. Of course, you’ll need a clear path that won’t have any sharp curves.

You’ll need to pry up one long side with some 2 x 10s as levers and short blocks to act as fulcrums. You may have to nail two of these together to prevent breakage. See if your base planks can act as rails. If not, you may need to temporarily nail a couple of 2 x 12s or 2 x 10s at least 12 feet long.

Use pipes or logs as rollers. Pry up your front end, then slip a roller underneath. Pry up the back side and put some more rollers underneath. Start pushing. You’ll need one person free to move the rollers. As you push the shed, the free helper takes the roller the shed just got past and moves it ahead of the shed along the path. It may take a while, but the more help you have, the faster the shed will move. Read my article How to Move a Shed – What Are the Options? for more detailed information on moving a shed.


All in all, a 12×12 shed is a really nice size, and the square shape allows for easy storage of larger tools and “toys.” There is plenty of room for shelving without having to avoid it while moving around inside. If you’ve got a sizeable yard, this is certainly a size you should consider.