When planning to build a shed or any other outdoor structure, choosing the right building materials is crucial for its stability and longevity.
The type of lumber used for the floor joists and wall framing can significantly impact the strength and weight capacity of the structure, as well as its cost and insulation capabilities.
Two of the most common options are 2×4 and 2×6 shed floor joists.
2×6 is stronger, can span longer distances, and can hold more weight, but it is also more expensive. 2×4 is a more affordable option suitable for smaller sheds or light loads.
In this article, we will explore the main differences between these two types of lumber and which one might be the best fit for your project.
2×4 and 2×6 Shed Floor: The Key Differences
Let me take you through the advantages and disadvantages of both 2×4 and 2×6 shed floor joists, their weight capacity, cost, maximum span, and more to help you choose the right option for your needs.
| Factors | 2×4 Shed Floor Joist | 2×6 Shed Floor Joist |
| Strength | Placed 16″ o.c., can bear significant loads | Placed 24″ o.c., must be spaced 16″ apart to realize increased strength, preferred in areas prone to earthquakes |
| Maximum Span | Up to 6’7″ at 16″ spacing, up to 7’11” at 12″ spacing | Maximum span of 9’8″ at 12″ spacing |
| Weight Capacity | 1,000 lbs vertically | Can support 53 lbs per linear foot when placed on edge, 662 to 998 lbs as a column, and 7,061 lbs when encased and blocked in a wall before buckling |
| Cost per 8′ length | $5 | $8 |
| Advantages | Suitable for smaller sheds, more affordable | Larger and stronger, can provide more space and greater security |
| Disadvantages | Weaker than 2×6, may not be suitable for larger sheds or heavy loads | More expensive than 2×4 |
Strength
When placed 16″ on center, 2×4 shed floor joists can bear significant loads but are weaker than 2×6 joists. They are best suited for smaller sheds and light loads.
2×6 shed floor joists are larger and stronger than 2×4 joists but must be spaced 24″ in the center or 16″ apart to realize increased strength. They are preferred in areas prone to earthquakes and are suitable for larger sheds and heavier loads.
Maximum Span
2×4 shed floor joists can span up to 6’7″ at 16″ spacing or up to 7’11” at 12″ spacing. Beyond these lengths, additional support is required.
2×6 shed floor joists can span a maximum of 9’8″ at 12″ spacing, providing greater shed design and layout flexibility.
Weight Capacity
A 2×4 shed floor joist can support up to 1,000 pounds vertically, making it suitable for most small shed projects.
When placed on the edge, a 2×6 shed floor joist can support up to 53 pounds per linear foot. As a column, it can withstand between 662 and 998 pounds of weight, and when encased and blocked in a wall before buckling, it can support up to 7,061 pounds of weight.
This makes it ideal for larger sheds and heavy-duty applications.
Cost
Using 2×6 lumber for wall framing is slightly more expensive than using traditional 2×4 studs, with an average increase of around $3 per 8-foot length.
However, since 2x6s can be framed at 24 inches in the center, fewer boards are needed overall, resulting in a minimal increase in cost.
For example, for an 8×8 shed, seven 2x4s are needed per wall, while only five 2x6s are required.
Assuming a cost of $5 per 2×4 and $8 per 2×6, using 2x4s would cost $35 per wall, while using 2x6s would cost $40 per wall, resulting in an extra cost of $20 for the entire shed.
This cost difference remains minimal even for larger shed designs. Overall, choosing 2×6 wall construction can be a cost-effective option due to the larger gaps between studs that keep the cost of using 2×6 lumber comparable to that of 2×4 lumber.
Advantages
2×4 shed floor joists are suitable for smaller sheds, and their affordability makes them accessible to a broader range of DIYers. They are also easier to handle and install.
2×6 shed floor joists are more prominent and stronger and can provide more space and greater security. Their increased weight capacity makes them ideal for heavy-duty applications, and their flexibility in shed design allows for greater customization.
Disadvantages
The main disadvantage of 2×4 shed floor joists is their weaker strength and lower weight capacity, which may limit their use in larger sheds and heavier loads.
The main disadvantage of 2×6 shed floor joists is their higher cost, which may be prohibitive for some DIYers on a budget. They are heavier and more difficult to handle and install.
When Should You Go For a 2×4 Shed Floor?
If you are building a simple storage area and plan to spend less time in the shed, 2×4 framing is a good option.
It is less expensive than 2×6 framing and will not take up as much interior space. A well-constructed 2×4 framing will withstand any snow load or wind storm, so there is no need to use 2×6 construction for a simple storage shed.
Additionally, if you have a large backyard and space is not an issue, you could use 2×6 lumber, but it would not provide significant benefits for a storage shed.
When Should You Go For a 2×6 Shed Floor?
If you are planning to use your shed as a work or living space, 2×6 framing might be a better option. It provides more options for insulating, allowing you to use R-22 batts for more efficient insulation.
Although you could use 2×4 framing to achieve the same R-value, you would have to add 1 12″ of foam insulation to the exterior of the shed walls, negating any cost savings you might have experienced.
Furthermore, 2×6 framing offers a better foundation for building a loft space above and enables you to frame your walls higher than 8′, allowing you to have an extra high ceiling or construct a loft in your shed.
When considering 2×6 wall framing, keep in mind that it will cost you more than using 2x4s. Also, special ordering doors and windows to fit 2×6 framing will cost you more if you want to have a nice, liveable, finished space in your shed.
If you have a small shed that is used for storage, 2×6 framing will not provide significant structural benefits and will take up more interior space than 2×4 framing.
Can you Use 2×6 Insulation in 2×4 Shed Walls?
It’s not recommended to use 2×6 insulation in 2×4 shed walls. The reason behind it is that batts made of fiberglass or stone wool rely on millions of tiny air pockets to reduce conductive heat transfer.
When you compress these air pockets, like when you force an R-22 batt into a 2×4 cavity designed for R-13 insulation, the insulation’s effectiveness becomes compromised.
To achieve the same R-value as a 2×6 wall, it’s better to use foam insulation on the outside of the 2×4 sheathing. This method also breaks the thermal barrier between the studs and sheathing.
However, it comes with an added cost of up to $25 for a 4×8 R-5 piece of exterior rigid foam insulation.
While more insulation results in better energy efficiency in a workspace or tiny house that isn’t a primary dwelling, the difference in energy savings between various insulation types over a year is negligible.
Therefore, it’s essential to focus on factors such as interior space and structural stability when deciding between 2×4 and 2×6 framing for shed walls.
Besides, since rigid exterior panels can always be added for insulation, it shouldn’t be the determining factor between the two framing options.
How Thick Should Exterior Walls Be?
The minimum thickness for shed exterior walls using 2×4 lumber is 5 inches, which includes the 1.5-inch by 3.5-inch studs and the additional thickness of the sheathing and siding.
The sheathing typically ranges from ⅝” to ⅜” thick, while the siding can be anywhere from ½” to 1” thick.
If you plan on adding insulation to your shed walls, the thickness will depend on the type of insulation you choose. You can insert more insulation between 2×6 lumber if you utilize batts as your insulation.
However, if you intend to add foam panels outside of your sheathing for additional insulation, you should expect a wall made of 2×6 lumber to be about 8″ thick.
It’s important to consider the size of your shed and the space it will occupy when designing your shed walls. If you have a smaller shed and limited space, using 2×4 framing can be perfectly acceptable.
However, if you plan to spend a lot of time in your shed or experience extreme temperature changes, using 2×6 framing will provide better insulation and maximize the efficiency of any heating or cooling source you use.
Final Verdict
In conclusion, when deciding between 2×4 and 2×6 shed floor framing, it’s essential to consider your project’s needs carefully.
While 2×4 framing is cheaper, 2×6 framing provides more strength and durability, making it a better option for larger or heavier loads.
Furthermore, using pressure-treated lumber or moisture-resistant materials for your shed’s floor frame is crucial to prevent rot and decay.
By taking the time to weigh the benefits and drawbacks of each option and assessing your project’s specific requirements, you can determine the best choice for your shed’s floor framing and ensure a sturdy and reliable structure that will last for years to come.
FAQ
What are the benefits of using a 2×6 shed floor instead of a 2×4?
One of the main benefits of using a 2×6 shed floor is that it is stronger and more stable than a 2×4 floor.
This is especially important if you plan on storing heavy equipment or machinery in your shed. Also, a 2×6 floor provides more insulation, making it easier to regulate the temperature inside your shed.
How many 2x6s do I need for a shed floor?
The number of 2x6s you will need for a shed floor will depend on the size of your shed. As a general rule of thumb, you will need one 2×6 for every 16 inches of joist spacing.
So, for a shed that is 10 feet by 12 feet, with joists spaced 16 inches apart, you would need approximately 30 2x6s.
What is best for shed flooring?
Vinyl rolls or tiles are an excellent choice for a shed’s flooring, given their waterproof, non-slip, and resistant properties to most common home pollutants. Maintaining and cleaning them is also an easy task.
How do I keep my shed floor from rotting?
The junction between the ground and the floor system is the most susceptible area to rot in a shed. Raising the storage facility slightly can provide optimal airflow.
The entire floor frame should be made of weatherproof materials to achieve maximum effectiveness.
Should I put plastic under my shed floor?
Using plastic underneath a shed can be beneficial, especially if it lacks heating or air conditioning, to avoid moisture buildup and mold development.
When building the shed on a concrete slab, placing a plastic barrier underneath it can prevent moisture penetration into the concrete.
