2x6 Or 2x8 For Deck Floor: Which Floor Joist To Go For?

Whether you’re aiming for a compact retreat or an expansive outdoor oasis, you must be stuck between choosing 2×6 or 2×8 for deck floor joists.

Don’t worry; we got you covered!

2×6 joists are moderately strong, suited for smaller decks, and offer a span capacity of up to 9ft 11in. With a load-bearing capacity of 53lbs/linear ft, they may be more prone to deflection. However, 2×8 joists are stronger, ideal for larger decks, with a span capacity of up to 13ft 1in and a load-bearing capacity of 70 lbs/linear ft. They are less prone to deflection and come at a slightly higher cost of $4 – $6 per linear ft.

In this comprehensive blog post, we’ll dive deep into the world of deck construction to help you make an informed choice.

2×6 Or 2×8 Joists For Deck Floor: Comparison Factors

Choosing the right joists for your deck floor is a critical decision that impacts both the structural integrity and overall functionality of your outdoor space.

In this blog section, we explore the comparison factors between 2×6 and 2×8 joists, helping you make an informed choice for a deck that stands the test of time.

Comparison Factors	2×6 Deck Joists	2×8 Deck Joists
Size	2 inches thick and 6 inches wide	2 inches thick and 8 inches thick
Strength	Moderately strong	Stronger than 2×6
Span Capacity	Spacing 12’’ – 9 ft 11 inches Spacing 16’’ – 9 ft Spacing 24’’ – 7 ft 7 inches	Spacing 12’’ – 13 ft 1 inch Spacing 16’’ – 11 ft 10 inches Spacing 24’’ – 9 ft 8 inches
Load-bearing Capacity	53 pounds/linear ft Live load – 40 pounds/sqft Dead load – 10 pounds/sqft	70 pounds/linear ft Live load – 50 pounds/sqft Dead load – 10 pounds/sqft
Deflection	More prone to deflection	Less prone to deflection
Deck Structure	Suitable for smaller decks or shorter spans	Suitable for larger decks or longer spans
Cost	$3.50 – $5/linear ft $35 – $50/10 ft board $48 – $64/16 ft board	$4 – $6/linear ft $40 – $60/10 ft board $56 – $80/16 ft board

Size

When it comes to size, 2×6 deck joists are like the slim and sleek runners of the deck world, measuring 2 inches thick and 6 inches wide.

On the other hand, 2×8 deck joists are the broader, brawnier siblings, boasting a width of 8 inches while maintaining the same 2-inch thickness.

They are like the heavyweight champions of deck construction.

Strength

In the strength department, 2×6 deck joists offer a moderate level of sturdiness. They can handle typical loads but might require additional support for heavier structures.

In contrast, 2×8 deck joists flex their muscles with greater strength. They can bear heavier loads without breaking a sweat, offering a robust foundation for your deck’s structure.

Span Capacity

Regarding spanning distances, 2×6 deck joists have their limits.

Depending on the spacing between the joists, they can reach spans of up to 9 feet and 11 inches when placed 12 inches apart or 7 feet and 7 inches when spaced 24 inches apart.

It’s like a nimble tightrope walker carefully balancing their steps.

On the other hand, 2×8 deck joists showcase their impressive reach, stretching up to 13 feet and 1 inch with 12-inch spacing or 9 feet and 8 inches when spaced 24 inches apart.

They can handle longer spans, creating more open and spacious deck designs.

Material	Joint Spacing	2×6 Deck Joist Span	2×8 Deck Joist Span
Southern Pine	12 inches	9 ft 11 inches	13 ft 1 inch
Southern Pine	16 inches	9 ft	11 ft 10 inches
Southern Pine	24 inches	7 ft 7 inches	9 ft 8 inches
Douglas Fir-Larch	12 inches	9 ft 6 inches	12 ft 6 inches
Douglas Fir-Larch	16 inches	8 ft 4 inches	11 ft 1 inch
Douglas Fir-Larch	24 inches	6 ft 10 inches	9 ft 1 inch
Redwood	12 inches	8 ft 10 inches	11 ft 8 inches
Redwood	16 inches	8 ft	10 ft 7 inches
Redwood	24 inches	6 ft 10 inches	8 ft 8 inches

Load-Bearing Capacity

When it comes to handling weight, 2×6 deck joists can hold their own.

They can support a load of around 53 pounds per linear foot, with a live load capacity of 40 pounds per square foot and a dead load capacity of 10 pounds per square foot.

However, if you’re looking for even more robust support, 2×8 deck joists are your go-to.

They boast a higher load-bearing capacity of approximately 70 pounds per linear foot, with a live load capacity of 50 pounds per square foot and a dead load capacity of 10 pounds per square foot.

They provide the backbone for sturdy and resilient decks.

Deflection

When it comes to deflection, 2×6 deck joists exhibit more flexibility. Under heavier loads, they may experience some bending or sagging, akin to a graceful dancer bending with the rhythm.

However, 2×8 deck joists take a stand against deflection. Their sturdy nature helps minimize bending and sagging, ensuring a more stable and solid deck structure. They are like the strong pillars that hold up the deck with unwavering support.

Deck Structure

Considering the deck structure, 2×6 deck joists are well-suited for smaller decks or shorter spans. They are ideal for creating cozy outdoor retreats or intimate gathering spaces.

2×8 deck joists offer the stability and strength required for larger decks or longer spans. They provide the framework for expansive outdoor entertainment areas or decks that extend further into the landscape.

Cost

In terms of cost, 2×6 deck joists offer a budget-friendly option. They typically fall within the price range of $3.50 to $5 per linear foot, with variations based on suppliers and lengths.

Additionally, a 10-foot board may cost around $35 to $50, while a 16-foot board could range from $48 to $64.

On the other hand, 2×8 deck joists come at a slightly higher price.

They are generally priced between $4 and $6 per linear foot, with a 10-foot board from $40 to $60 and a 16-foot board from $56 to $80.

How To Install A Deck Floor? A DIY Guide

Building a deck floor can enhance your outdoor living space and provide an inviting area for relaxation and entertainment.

This step-by-step DIY guide will walk you through the process, ensuring a successful deck floor construction project. Get ready to embark on a rewarding journey of craftsmanship!

Step 1: Planning and Preparation

Determine your deck floor’s desired dimensions and layout.

Use string lines and stakes to mark the perimeter of the deck area.

Check local regulations and obtain necessary permits for deck construction.

Consult with local authorities to ensure compliance with building codes.

Make a list of required materials, including deck boards, joists, concrete footings, screws, and nails.

Gather essential tools such as a circular saw, drill, hammer, post-hole digger, and safety equipment.

Tools Required

Measuring tape

String lines
Stakes
Level

Circular saw
Drill
Hammer

Post hole digger
Safety goggles
Gloves

Step 2: Building the Foundation

Carefully consider the desired layout and dimensions of your deck.

Mark the precise locations where the footings will be installed based on your deck design and local building codes.

Use a post-hole digger to dig holes for the footings at the marked locations.

Ensure that the diameter and depth of the holes meet the requirements specified by your local building codes.

Typically, the diameter of the holes should be about three times the width of the deck posts or as specified by your building plans.

The depth of the holes will depend on the frost line in your region and the stability of the soil.

Prepare a concrete mix according to the manufacturer’s instructions. A typical mix consists of cement, sand, and gravel in the appropriate ratios.

Place the concrete mix into the holes, filling them up to ground level. Leave about 2 inches of space below the ground level to allow for proper drainage.

Use a shovel or trowel to level the surface of the poured concrete, ensuring it is even and free from any lumps or bumps.

Check the levelness of the concrete surface using a level to ensure it is perfectly flat and aligned with the desired height for your deck.

Follow the manufacturer’s instructions regarding the curing time for the concrete. Typically, it takes several days for the concrete to cure fully.

Concrete footing brackets may be necessary for certain deck designs or to meet specific building codes.

These brackets provide additional stability and support for the deck posts by connecting them to the concrete footings.

Attach the concrete footing brackets securely to the cured concrete using appropriate anchor bolts or screws.

Tools Required

Post-hole digger

Shovel
Wheelbarrow
Level

Step 3: Framing the Deck

Determine the desired height of your deck and mark the location where the ledger board will be attached.

Use a level to ensure the ledger board is perfectly horizontal.

Securely fasten the ledger board to the house’s structural framing using lag bolts.

Ensure the lag bolts penetrate through the ledger board and into the solid framing members of the house.

Position the deck posts into the pre-dug footings, aligning them with the layout of your deck.

Use a level to check that each post is plumb (perfectly vertical) and level (parallel to the ground).

Make any necessary adjustments by adding or removing soil from the footings to achieve the correct height.

Depending on your local building codes and design preferences, you can use either concrete or metal post anchors.

For concrete anchors: Pour concrete around the base of each post, ensuring it fills the entire footing and provides stability.

For metal post anchors: Attach the anchors securely to the footing using anchor bolts or screws. Then, insert the posts into the anchors and tighten any necessary bolts.

Cut the rim joists to the appropriate length and attach them to the ledger board and deck posts using nails or screws.

Ensure the rim joists are level and aligned with the ledger board and posts.

Use a level to check for horizontal alignment and adjust as needed.

Securely fasten the rim joists to the ledger board and posts to create a sturdy framework for the deck floor.

Tools Required

Drill

Lag bolts
Level
Post anchors

Concrete
Nails or screws

Step 4: Installing Deck Joists

Consider the load requirements and local building codes to determine the appropriate spacing between deck joists.

Typically, the spacing is set at 16 inches on center (measured from the center of one joist to the center of the next).

Mark the locations where each joist will be installed along the ledger board and rim joists.

Securely attach joist hangers to the ledger board and rim joists at each marked location.

Slide the ends of the joists into the joist hangers, ensuring a snug fit.

Use nails or screws to secure the joist hangers to the joists, providing solid and reliable connections.

Place a level on top of each joist and adjust their positions as needed to achieve a perfectly level surface.

If a joist is slightly higher than the adjacent ones, you can use a hammer and chisel to trim it down.

Conversely, if a joist is lower, you can add shims (thin pieces of wood) to raise it to the desired level.

Continuously check the level of the deck joists as you progress.

Adjust the footings or modify the joists accordingly if you find any significant variations or inconsistencies.

Ensure that the joist hangers properly support all joists and are level across their entire length.

Tools Required

Joist hangers

Nails or screws
Level
Shims

Step 5: Laying the Deck Boards

Consider the desired aesthetic and functional aspects when choosing the orientation and pattern for your deck boards.

Common options include horizontal, diagonal, or herringbone patterns.

Plan the layout in advance to ensure a visually pleasing and balanced appearance.

Begin at one corner of the deck and place the first deck board perpendicular to the joists.

Leave a small gap (around 1/8 to 1/4 inch) between each board to allow for natural expansion and contraction of the wood.

Use a spacer or a suitable object to maintain consistent spacing between the boards.

With the first deck board in place, use a drill to pre-drill pilot holes near the ends of the board, slightly narrower than the diameter of the screws or nails.

Fasten the deck board to the joists with screws or nails, ensuring they penetrate the board and securely attach to the joists.

Continue this process for each deck board, working along the length of the deck.

As you secure each deck board, ensure they are flush with the edge of the joists and maintain consistent spacing.

Use a measuring tape or spacing tool to ensure an even gap between each board.

Check periodically with a level to maintain a level surface.

Use a chalk line or straight edge as a guide to maintain straight and aligned deck boards.

Snap a chalk line along the edge of the first row of deck boards to provide a reference line for subsequent rows.

Align the next rows of deck boards with the chalk line, ensuring they are straight and parallel.

Tools Required

Circular saw
Measuring tape
Drill

Screws or nails
Chalk line

Step 6: Finishing Touches

Sand the deck surface to smoothen any rough edges or imperfections.

Apply a weather-resistant sealant or stain to protect the wood from the elements.

Install railings and stairs according to your design preferences and local building codes.

Ensure they are securely fastened and provide adequate support and safety.

Tools Required

Orbital sander
Sandpaper
Paintbrush or roller

Drill
Screws or nails
Saw

Remember to prioritize safety and consult local building codes throughout the construction process. Get ready to enjoy the fruits of your labor and create lasting memories on your newly constructed deck floor.

Additional Maintenance Tips For Your Deck Floor

A well-maintained deck enhances the beauty of your outdoor space and ensures its longevity. Regular maintenance is essential to protect your deck floor from weathering, rot, and other issues.

Cleaning and Sweeping

Start by removing any debris, leaves, or dirt from your deck floor using a broom or leaf blower.

Next, clean the deck surface with a mild detergent mixed with water and scrub it gently using a stiff brush or a deck cleaner.

Rinse off the cleaning solution thoroughly with a garden hose or a power washer on a low setting.

Benefit

Regular cleaning and sweeping prevent the buildup of dirt, mold, and mildew, which can cause discoloration and promote decay. It also helps maintain a clean and appealing deck surface.

Additional DIY Tip

Consider using a deck brightener or oxygenated bleach solution to remove stubborn stains, such as grease or rust. Apply the solution as directed, scrub the stained area, and rinse thoroughly.

Inspecting and Repairing

Regularly inspect your deck floor for any signs of damage, such as loose or splintered boards, protruding nails, or cracks.

Replace any damaged or rotted boards promptly, ensuring they are securely fastened to the underlying structure.

Check the integrity of railings, stairs, and any other structural components, and repair or reinforce them as needed.

Benefit

Timely inspection and repairs prevent further deterioration and potential safety hazards. You can promptly maintain your deck’s structural integrity and safety by addressing issues promptly.

Additional DIY Tip

Use a moisture meter to assess the moisture content of the wood. This can help identify areas that may be prone to rot or decay. Focus on these areas during inspections and take preventive measures, such as applying wood preservatives or increasing ventilation.

Sealing or Staining

Determine if your deck floor requires sealing or staining by performing a simple water test.

Sprinkle water on the deck surface; the sealer is still effective if it beads up. If it soaks into the wood, it’s time for resealing.

Clean the deck thoroughly and allow it to dry completely before applying a suitable sealer or stain.

Follow the manufacturer’s instructions for application, ensuring even coverage and sufficient drying time.

Benefit

Sealing or staining your deck protects against moisture, UV rays, and general wear and tear. It enhances the wood’s natural beauty, prolongs its lifespan, and prevents fading or graying.

Additional DIY Tip

Before applying the sealer or stain, sand any rough or splintered areas of the deck to create a smooth surface. This enhances the overall appearance and ensures better adhesion of the protective coating.

Regular Maintenance Checks

Conduct regular maintenance checks throughout the year to ensure the overall condition of your deck.

Look for signs of pest infestation, such as termites or carpenter ants, and take appropriate measures to address the issue.

Trim nearby vegetation to prevent it from touching or encroaching on the deck, which can lead to moisture accumulation and potential damage.

Benefit

By performing regular maintenance checks, you can identify and address potential problems before they worsen. This proactive approach helps extend the lifespan of your deck and reduces the likelihood of costly repairs.

Additional DIY Tip

Apply a water-repellent solution to your deck after sealing or staining to provide an extra layer of protection against moisture. This can help prevent warping, splitting, and other water-related damage.

Bottom Line

In conclusion, deciding whether to use 2×6 or 2×8 joists for a deck floor depends on a number of factors, including the deck size, the type of wood, the expected load, and the local building codes.

Generally, 2×6 joists are sufficient for most decks, but 2×8 joists may be required for larger decks or decks subjected to heavy loads.

It is always best to consult a professional contractor to determine the best joist size for your specific deck.

FAQ

How far can a 2×6 span without sagging?

The International Residential Code (IRC) 2021 sets forth the maximum spans for 2×6 joists in various applications.

As a floor joist, a 2×6 can span a maximum of 12 feet 6 inches.

It can span a maximum of 20 feet 8 inches as a ceiling joist.

As a deck board, it can span a maximum of 24 feet. And as a deck joist, it can span a maximum of 9 feet 11 inches.

It can span a maximum of 18 feet as a rafter.

What is the maximum hole size for a 2×6 floor joist?

The maximum hole size for a 2×6 floor joist is 1-13/16 inches in diameter.

This equals a 7/8-inch deep and 1-13/16-inch wide notch. The hole or notch can be at most 2 inches to the top or bottom of the joist.

It is important to note that these are maximums and that the actual hole or notch size required may be less depending on the specific load conditions.