Take the time to build a strong foundation and you'll enjoy your Summerwood Garden Shed for years to come.
In this section, you will find detailed information about garden shed foundations - from the various options available for stabilizing or leveling the base of your structure, to tips on how the components of your garden shed foundation should be laid out. How long it takes to create your garden shed foundation will depend on the size of your structure and the type of foundation you choose.
If the location of your new Summerwood garden shed is on soft, sloped, or uneven ground, do not worry. This section will show you how to build a solid foundation so that your garden shed is level and sturdy regardless of the type of ground it rests on.
There are a number of effective ways to create a level foundation for your garden shed. Usually, the function of your shed will dictate the type of foundation you choose. For example, a more complex shed with plumbing and electrical considerations will require a more heavy duty foundation, like a concrete pad. We have listed many different foundation options that you can reference when deciding on what's best for you:
Level of Difficulty: Simple
Patio stones are the simplest method for supporting a wooden floor. They provide an effective foundation when the ground is relatively level (ie within 12" from side to side or front to back) and the structure is not too large. If your shed is larger then 150 sq. ft. you may want to consider one of the other foundation options. Patio stones are readily available at your local building supplier and are usually reasonably priced.
A Word About Patio Stones
- In order to use patio stones, your shed must have a floor (included with your shed kit package).
Patio stones are not shipped with your kit.
Patio stones are shown under a wooden floor.
Patio Stones & Your Garden Sheds
Lay out your patio stone foundation proportionately to the floor frame by placing your patio stones approximately 3-feet apart underneath the 2 x 6 pressure treated runners. Your floor frame will have the dimensions of your structure (e.g. 8ft x 12ft).
Ideal placement of patio stones underneath the floor runners.
Notice how the patio stone does not extent past the floor's exterior.
- Your patio stones should not extend past the perimeter of your floor (past your rim joists), as this will affect the installation of the skirting. Ensure that each patio stone is placed "squarely" underneath the runners.
The next step is to level your entire floor using shims. Any material that can be used to level your floor on patio stones are called shims. They can be made of wood or even metal. Cedar shims (cedar shingles) are a popular choice because they are durable, long lasting and resist decay. You will likely have some wood scraps lying around that can be used to shim your shed floor.
Cedar shingles are used to shim the garden shed floor and make it level.
No matter the size of your shed floor or how many runners you have in place, ensure that your patio stones are positioned underneath each runner squarely.
Position your patio stones squarely underneath each runner for maximum floor support.
What We Recommend
When using patio stones to level your shed foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
To guard against a sinking floor, use 2" x 12" x 24" (or 24" x 24") patio stones to distribute your shed foundation evenly across a large surface area.
a 2 x 12 x 24 patio stone is shown
- Whether you use small or larger-sized patio stones, remember to space them apart accordingly. For example, if you use 12" x 12" patio stones, position them closer to each other. If you use 24" x 24" patio stones, you can place them further apart.
- You may want to consider the option of adding an even layer of crushed stone underneath your patio stones. This can help with drainage and achieve a more level ground for your foundation.
Level of Difficulty: Simple
Structurally a very strong foundation option, cinder blocks are another easy way to level your garden shed floor. They can be purchased from your local building supplier and may be used to level a shed on a moderately steep slope.
A Word About Cinder Blocks
Cinder blocks are not included in your kit.
cinder blocks may be used if the ground slopes considerably
Cinder Blocks & Your Garden Shed
Here's what you need to know when laying the foundation for your Summerwood garden shed floor using cinder blocks:
Cinder blocks generally have dimensions of 8" x 16". While they provide uncompromising strength, their size and weight may cause your garden shed to sink if the ground below it is soft. Use multiples of cinder blocks and overlapping rows to guard against any sinking.
typical cinder block
What We Recommend
When using cinder blocks for your shed foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
- Attach a skirt to your garden shed to hide the cinder block foundation. We provide one row of skirting which you can use to cover the foundation underneath. Skirting can also help to keep pesky critters out from the bottom of your shed. If you'd like more rows of skirting (because your structure is elevated), they can be purchased when you place your order.
Level of Difficulty: Moderate
Super spikes are generally used in situations where one end of your garden shed needs to be raised to provide a level foundation and you do not want to go through the trouble of pouring footings. In some instances, you may want to elevate the floor of your Summerwood shed; super spikes enable you to do this.
Before you visit your local building supply store to purchase super spikes, check your jurisdiction's building codes for rules and regulations about using them (there may be some special darkgreen rules you'll have to consider).
A Word About Super Spikes
- Super spikes should not be used if your area is prone to frost conditions. Typically, super spikes are used in warm climates, which do not experience frost.
- Super spikes are not included with your kit.
Typical installation of super spikes.
What We Recommend
When using super spikes for your shed foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
- If your garden shed is elevated, you can attach a skirt, lattice (available at your local hardware store), or stairs to hide your foundation and super spikes. If you'd like material to build a set of stairs, let us know at the time of your purchase and we'll provide it.
Six inches of skirting is included with your kit. If you require more, please let us know at the time of your purchase.
a lattice skirt finishes off the base nicely.
Take advantage of a steep slope by adding stairs and a landing.
Level of Difficulty: More Challenging
Sonotube, also known as concrete footings, are used in situations where a garden shed needs to be raised, the ground is very uneven, or a building permit is required (i.e. in some areas a building permit is required if the area of the structure exceeds 110 square feet). Check your jurisdiction's building codes for rules and regulations.
Concrete footings can be expensive to install, as they must be used for your entire garden shed. However, they provide the necessary support for structures that are, for example, situated on a steep slope.
A Word About Sonotube/Concrete Footings
Concrete footings are not included in your kit. If you prefer some experienced help when pouring your concrete footings, simply tell us. We are happy to recommend contractors in your area.
An example of what concrete footings look like installed on a slope.
Concrete Footings & Your Garden Shed
Here's what you need to know when laying the shed foundation for your Summerwood floor using concrete footings:
- Before you begin digging holes for your concrete footings, it is very important to check with your local area's building codes for rules and regulations. You can also contract the services of an experienced building inspector to help you determine the appropriate size and depth of your concrete footings, before and after they have been installed.
- Contact your local utility company to check if you will be digging near underground cables or gas lines.
- Once you have confirmed the legal size and depth of your concrete footings, you can dig the holes by hand with a digger or ask a friend to help. Your local hardware store will be able to offer other digging suggestions that work optimally in your area.
- When your holes are complete, you can either pour concrete directly into the holes and set your structural beams onto the concrete later, or intersperse tubes in the ground and pour concrete until it is level. Later, the tubes will be cut and your structure affixed to the tubes.
- Concrete footings should generally be 10 inches in diameter and drilled well below the frost line. The positioning of your concrete footings should be similar to the layout for patio stones (Link to Patio Stones-Foundations page). We can provide that to you when you purchase a kit from us. Please note that this does not apply to plans purchases.
- Let your concrete footings set thoroughly and properly.
- If you'd like to lay a gravel base to ensure that water doesn't accumulate around your footing, 6" is the recommended amount.
- To easily attach your shed to the concrete footings you've poured, consider sinking a bolt into the footing. It's not necessary to do this but it may make your installation easier.
Depiction of a standard concrete footing with a gravel base and a j-bolt that can be used to affix a garden shed floor to the footing.
What We Recommend
When using sonotube/concrete footings for your garden shed foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
- We recommend hiring an experienced contractor who is also aware of local regulations and will ensure that your structure complies with regional building codes.
Set your footings 6" from the end of the beam and sides
An example of what concrete footings look like installed on a slope.
Small Sheds - using runners
Use the supplied runners. Simply J bolt thru the runners and secured with a washer and nut are the easiest and simplest way to go. They should be placed every 4' in any direction.
Large Sheds - using beams
Use 6x6 post brackets in your concrete footings. There are several varieties, visit your local hardware store to find which one is common in your area.
The floor will rest on you 6x6 post piece. You will have to level your floor and the easiest way to do so is with these posts. Cutting the small post pieces to obtain level is far easier than trying to shave beams themselves.
Framing and Beams/Runners
Think of our floors in building depths. Our floor joists always run from the front of the building to the back.
Unless otherwise upgraded, our floor members come in the following dimensions
|Building Depth||Lumber Dimension|
|4' - 8'||2x4|
|8' - 13'||2x6|
Beams and Runners will run the length of your building. From sidewall to sidewall. They run the opposite direction of your floor joist.
Footings spacing from the front of the building to the back should be approx. 5' - 6' apart.
Use the following chart to space the footings from side to side.
|Spacing of concrete footings|
|2 x 4 floor joists||2 x 6 floor joists||2 x 8 floor joists|
|Building length||(2 - 2 X 6 Ply Beam)||(2 - 2 X 8 Ply Beam)||(3 - 2 X 8 Ply Beam)|
Level of Difficulty: Elaborate
Concrete pads provide a concrete base onto which your garden shed walls can be mounted. This foundation option is generally used if you are:
- Storing heavy equipment that cannot be supported by a wooden floor.
- Housing heavy machinery or vehicles.
- Housing pool equipment (ie heater, filter, pump).
- Installing a plumbing system.
Concrete pads are also used for larger buildings that may require a permanent foundation.
A Word About Concrete Pads
- Concrete pads are an expensive foundation option and we recommend that you enlist the services of an experienced contractor who is aware of local regulations and will ensure that your structure complies with regional building codes.
- Pouring a concrete pad means you have the option of not having a floor. In this case, the walls would be mounted directly into the concrete using a pressure treated bottom plate and a gasket seal to prevent moisture buildup.
- If you are replacing an existing shed with a larger size it is possible to frame on to the existing concrete pad. Using pressure treated materials you can extend the pad so that the size matches that of your new structure.
An example of a shed on concrete pad
Concrete Pads & Your Garden Shed
Here's what you need to know when laying the foundation for your Summerwood garden shed using a concrete pad:
- Before you begin pouring your concrete pad, it is very important to check with your local area's building codes for rules and regulations. Frost lines and seismic considerations will all dictate the type of pad and shed foundation you can build.
- If you enlist the services of an experienced contractor, they will likely select the appropriate type and amount of concrete mix for you. Choosing the right mix depends on the climate in your area (i.e. warm or cold) and the type of shed you will be erecting on the concrete pad. If you've elected to mix your own concrete, contact your local building supplier for assistance. They will also be able to help you determine what tools you will need.
Once you have chosen the site for your concrete pad, you will need to dig a trench. We recommend a 3-foot wide trench, but size will vary depending on your location. Grade or level the center of your trench.
Dig a trench to start building your concrete pad.
- Fill the bottom of your trench with crushed stone to maintain proper drainage.
Construct a concrete footing form using stakes and 2" x 8" lumber to mark the corners of your pad. It will be like building a sandbox or mold for your concrete mixture later. Ensure that your corners and the box are square.
A concrete form will keep your concrete in place
It is very important to pour a concrete pad that is the same size as your garden shed. Do not pour your pad according to your structure's exterior dimensions, which tend to be bigger than the actual building (siding allowances are not included in the measurement because they are positioned over the concrete pad).
If you pour a concrete pad that is bigger than your building measurements, you will increase the likelihood of water leaking into your building (creating a proper seal between your wall and your concrete pad is difficult).
- Pour your ready-mixed concrete into the mold you've created. Agitate the concrete to work out air bubbles. Level the concrete and use a piece of lumber (e.g. 2 x 4) to screed (i.e. smooth out) the surface of the pad. Apply more concrete to the sunken areas to bring the entire pad up to the same level.
Next, use a float to further smooth out the surface of your concrete pad. This will be like applying icing on a cake but without all the fun decorative whorls. Keep going over the concrete until you have worked out any moisture or remaining air bubbles. Avoid marring the surface of your pad.
An example of a smooth concrete pad
- When your concrete pad begins to set, run an edging tool along the inside of the mold. This will be like removing a cake from its baking tin. This technique will help make it easier to remove the forming boards later.
- Properly finish and seal your concrete pad using one of the following methods so that your floor lasts for as long as you have your shed. Try:
- Creating a slightly grooved surface so no one slips on your floor. Do this when the concrete has yet to set fully.- Cover your pad and allow the concrete to set evenly for approximately 48 hours.- Apply a protective concrete sealer.
There are several ways you can affix your walls to your finished concrete pad: use a J-bolt (available through any building supplier) or a concrete screw (Tapcons). Using a heavy drill, screw your J-bolt or Tapcon through the bottom plate and into the pad. We recommend that you use 41/2-inch screws and place them approximately every 12 to 16 inches apart.
A picture of a tapcon
Our siding is designed to overhang the bottom plate of the walls by approximately 1 inch. Should your concrete pad be slightly larger then the structure, simply saw off the overhang so that the bottom of the plate and the siding are flush with each other.
Make sure your bottom plate and siding are flush
What We Recommend
When using a concrete pad as your shed foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
- Always check with local contractors and/or building departments prior to pouring a concrete pad.
- Consider installing gutters to help redirect water away from your foundation and walls. This is always a useful addition, especial darkgreenly if your concrete pad is larger than your garden shed.
- If you are installing conduits for electrical service or plumbing, you must do so at least 4 1/2 inches from the edge of the pad so that the walls will have room to sit.
- Pouring a partial concrete pad tends to create problems in the future (with warping and the 2 foundations in use might sink or move at different times and degrees). We recommend that you pour an entirely new pad if necessary. Extending existing pads is possible but not advisable.