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How Do I Determine the Best Size Shed?

The size of your shed is one of the biggest decisions you will need to make in shed planning. It’s much better to find that you chose a size that has more room than you thought than to find that all the items you wanted to store there don’t fit. Nobody ever had problems filling up extra space.

The easiest way to get the right size shed is to make a list of what you’re going to store in the shed, or what you plan on using it for. Make a list of items you are going to store and their size on a piece of paper and add at least 25% more space.

How Do You Know What Size Shed to Buy?

First, determine what restrictions you’re building and zoning codes may have on the size and placement. You may find that there are fewer choices than you thought for placement of your shed, and this may make access to the shed awkward with a larger shed or it may restrict the size of your shed entirely.

Ryans Shed Plans

Homeowner’s associations typically will have even more restrictions, perhaps even having you keep your shed out of sight of the street. Once your shed site is chosen, figure out how you will use the shed and what kinds and sizes of things you intend to store there. Remember to plan for seasonal storage, such as storing summer things there through the winter. Plan for future needs as well, perhaps getting a slightly bigger shed than you think you will need right now.

What Size Shed Do I Need a Permit For?

This varies with the local regulations, but in general, any shed over 100 or 120 square feet in size will require a permit. Whatever size shed you have, if you plan to run plumbing or electricity to it, you’ll need a permit. Some localities have limits as to the height of the shed or the type of foundation used.

In addition, some places require a permit if you are building the shed on the property, no matter the size, rather than installing a prefab shed. They want to be able to inspect the shed to make sure it will be sturdy and won’t blow out into the street during thunderstorm wind gusts.

Even if you don’t need a permit for your shed, you still may have some zoning regulations that you’ll have to follow. These can include how far from your property line and other buildings your shed is permitted to be, whether it will be under or above utility lines, and other things.

There may be utility easements you need to stay away from. You may be required to put it in the back yard, and even out of sight of the street, especially if you live in a homeowner’s association. You may be required to anchor your shed to the ground or concrete.

It’s vital that you find out if you will need a permit for your shed. If so, you need to know what paperwork you will need to provide, such a building plans, foundation plans, electrical or plumbing schematics, and a site plan to check for placement. If you find out later that you should have gotten a permit, the penalties can be expensive.

Ryans Shed Plans

They can range from $250 to $2,500 per day until you get the permit, and if it’s a busy building time in the area you may have a waiting period for approval. Some areas even assess jail time. Having your shed built in the wrong place according to regulations may get you an order to move the shed, even if it’s bolted to a concrete pad, or just remove it entirely. You won’t be able to plead ignorance, as all it takes is a phone call to find out if you need a permit. To get more information on permits read my article Do You Require a Building Permit For a Storage Shed?

What is a Standard Shed Size?

There is no real standard size for a shed, but the most common size is six feet by eight feet. This will usually provide storage for the average homeowner with a push mower and a few garden tools and perhaps some lawn furniture over the winter.

How Big a Shed Can I Put in My Backyard?

In addition to the questions of building permits and restrictions, some areas limit the size of any outbuildings on the property. This usually comes in the form of a building size in relation to the property size, such as stating that an outbuilding cannot take up more than 20% of the backyard area. Some places also have restrictions on the height of the shed.

How to Estimate the Size Shed I Need?

Usage: How will you use the building? Is it going to be used solely for storage or do you want to use at least part of it for a workshop? You will want to plan for shelving and storage besides having your workspace and even plan for a workbench, depending on the type of work you want to do.

Height will play a part, as the attic space can be used for additional storage. You also want to make sure you’ll have room to move around easily to find and access smaller items once everything is in there.

Items: What kinds and sizes of things do you want to store in your shed? For homeowners with smaller yards, room for a push mower and a few gardening tools will be sufficient. If you have a large lot or some acreage, you’ll need room for a riding mower and maybe an ATV. You might have a tiller or a large toolbox or ladder. You’ll want to leave room for seasonal items, such as outdoor toys and summer lawn furniture and your grill. Read my article What Can I Safely Store in a Shed? to find out which items you can store safely in a shed.

Future space: The amount of storage space you may need in the future is something to consider. You don’t want to find out that you’ve already outgrown your shed in just a few years. If you have future plans for a pool in a few years, remember that you’ll need a place to store the pool items during the winter.

If you’re just starting out and haven’t started a family yet, remember that outdoor children’s toys need someplace safe to stay during winter also. You may decide to put in a large garden at some point, with extra storage space needed for the tiller, fertilizer and gardening tools.

If your kids are getting to be teenagers, at some point they’ll be gone and you may want to convert your shed or part of it into a workspace or outside office, so that possibility should factor in as well.

Property size: Sheds tend to be sized in relation to the size of the yard you have. That’s because small yards don’t need a huge riding mower to keep trimmed and have smaller gardens. Medium yards may need an 8 x 10 foot shed, while a larger one may do better with a 12 x 12 size.

Ryans Shed Plans

Zoning restrictions: Zoning plays a big part in the decision of the size of your shed. Restrictions on placement, such as a certain distance from property lines, other buildings, utility lines, easements and other things may limit the size shed you can have.

In addition, some localities limit the size of outbuildings to a percentage of the total backyard area. There may be a limit on how many outbuildings you are permitted. If you live in a homeowner’s association, there may be even more restrictions. Check out my article How Do I Choose the Right Size Storage Shed? for tips on choosing the perfect shed.

Can You Put a Shed Next to a House?

Most localities have restrictions on how close your shed can be to other structures, as well as property lines and fencing. You don’t have to live in a town or city to have these restrictions, as counties usually have their own building codes and restrictions as well. In addition, some states have many more restrictions on building than other states.

For instance, one state may require that any sewerage or septic system and piping for a home must be mapped out. These plans are kept at city or county offices. Another state may not have any such requirements, and a new homeowner who wants to dig in his backyard may have a hard time finding out where the septic lines run. You may be able to build a lean-to shed against a garage, check out my article Can I Build a Shed Attached to a Garage? for more information.

What Size Shed Do I Need for a Riding Lawn Mower?

For a riding mower or other similarly large item, a 10 x 12-foot shed should be sufficient. If you have other large items as well, such as ATVs or a free-standing toolbox, you may need more room. Remember to keep enough space to move around in the shed freely, even when all your items are in there.

You don’t want to have to squeeze between your mower and the wall to look on the shelves for things or find that you have to move the ATV out of the shed before you can open your toolbox drawers.

How Can I Increase the Size of My Existing Shed?

Depending on how the shed is constructed, it is possible to add on to a shed to extend it if building codes and zoning permit. Make sure there are no underground utilities nearby. You may need a building permit for this addition as well.

A lean-to added to the side of the shed is the easiest type of addition to construct. Use 4×4 posts at each end of the shed and two more to create new corners as far out as you want the extension. Six to eight feet is best. Dig holes for the posts about 2-1/2 feet deep. Pour in some gravel and then concrete to set the posts.

The concrete should extend a couple of inches above the ground to keep your posts away from the soil. This can be done using forms. The posts should be an inch shorter than the side of the shed itself to allow for water runoff.

Shed Plans
Shed Plans

Nail 2 x 4 inch boards across the posts all around to make a frame. Make a door opening on the existing side of the shed with a horizontal header board and studs from the header board to the floor. Cut the doorway out from inside your shed. You can put your chosen siding on all three sides of the new space or leave one side open.

Plywood and shingles or other roofing material go on last. Make sure to have some metal flashing at the place where the new addition’s roof joins the existing shed to keep water from seeping down between the shed and the addition. You can build a floor or leave the addition with a dirt floor.

You can also buy a greenhouse kit to add space to your shed. There are some that are formed into a lean-to shape meant to be put against a building. Some even include their own door. These are easier to assemble than building an addition from scratch and provide more room to store things that don’t need to be kept out of sight for security reasons. If necessary, you can always cover the glass with an opaque film to keep prying eyes off your storage items.

If you’re really ambitious you can build a real addition. This will entail removing the existing siding from one side of the shed and building new walls. Dig out a foundation for the new addition, constructing it the same way the shed foundation was constructed.

Don’t forget to use a foot of gravel around your new space for drainage. The studs for your new part should be spaced 16 inches apart. If you can get siding to match the rest of your shed, you can save money by reusing the siding you removed to attach the addition. Using the same kind of roofing will help tie it all together as well.

Remember to have a slight slope to the new roof for rain drainage. Add flashing extending four inches under the shingles on the shed and extending four inches down your new roof. You can read my article Can You Build a Shed Without Plans? if you want more information on adding an addition or doing the work yourself.


Planning for your shed is much like looking for a house to buy. You figure out how many bedrooms and bathrooms you need, how large your kitchen should be, and so forth. In the same way, you need to figure out how you plan to use a shed and what you want to store in it, keeping your eyes open for future needs. If you find that the shed you get has more room than you need, don’t worry, somebody else in the family will fill it up for you.