Avoid Costly Mistakes When Building Your Deck

Avoid Costly Mistakes When Building Your Deck: Follow This Step-by-Step Plan

Decks and DIY projects often go hand in hand. As a contractor, I frequently encounter situations where someone has attempted to DIY their deck or hired a friend or a “budget-friendly contractor.” Inevitably, I receive calls much sooner than expected for repairs. A well-built and well-maintained pressure-treated deck can last up to 50 years! However, certain mistakes can reduce this lifespan to just 5-10 years, sometimes even less.

Common Mistakes to Avoid

Improper Structure

This can be broken down into three key areas: securing the ledger board, foundation, and joist size.

Securing the Ledger Board

• Lack of Fasteners: Often, I see only 2 or 3 lag bolts used over a 16’ span. This insufficient fastening leads to sagging, pulling loose, and potentially falling off within a few years.
• Improper Anchoring: Using concrete anchors in non-structural brick can crack the brick, compromising both the deck and the entire wall, possibly pulling out whole bricks from the bottom.
• Incorrect Siding Attachment: Securing the ledger board to the siding, or even over the siding to the proper framing, causes issues if you ever replace your siding. This method leaves holes in the siding that are difficult to waterproof, leading to water ingress, the primary cause of home damage.

Foundations and Footings

• Undersized Footings: Footings that are too small will sink.
• Shallow Footings: Footings not set at least 48” deep will heave and move with the frost line.
• Improper Pouring: Pouring footings around a post in one pour can cause the post to slip, as if there were no concrete at all. Concrete poured around posts can trap moisture, leading to rot and rapid deterioration.

Joist Size

• Under-sized Joists: Using joists that are too small and over-spanned leaves your deck feeling like a trampoline and prone to cracking over time.

Other Common Issues

• Improper Fasteners: Using non-galvanized nails or screws causes rust, leaving rust spots on your finished deck and compromising its structure within a few years.
• Lack of Joist Hangers: Not using hangers for the joists can cause sagging unless properly toe-nailed. Regular screws used for joist hangers can snap and fall off under load because screws lack the tensile strength that nails possess. Tensile strength refers to the ability of a fastener to withstand pulling forces perpendicular to its length.

Below, I have put together a detailed plan, from start to finish, that will help you build your deck to last for decades. Whether you’re planning to DIY or looking to hire a contractor, this guide will ensure your deck stands the test of time and help you choose a trustworthy contractor if needed.

Step 1: Planning Your Deck

The planning stage is crucial to ensure your deck meets your needs and complies with local regulations. Proper planning will save you time, money, and headaches down the line. Here’s a detailed guide to help you through this important phase:

Decide the Location

1. Assess Your Yard: Look at your yard and decide where the deck will be most functional and aesthetically pleasing. Consider the natural flow from the house to the yard, as well as the view from the deck.
2. Consider Sunlight: Think about how much sunlight the area receives. Do you want a sunny spot or some shade? This will affect your choice of materials and whether you need to plan for shade structures.

Determine the Size and Shape

1. Functionality: Determine how you plan to use the deck. Will it be for entertaining, dining, or relaxing? The intended use will influence the size and layout.
2. Proportion: Ensure the deck is proportionate to your house and yard. A deck that is too large or too small can look out of place.
3. Design: Decide on the shape of the deck. Rectangular and square decks are the most common, but you can also consider more complex shapes to add visual interest.

Consider the Height

1. Ground Level: Measure the height from the ground to where the deck will attach to the house. This determines if your deck will be at ground level, raised, or multi-level.
2. Basement Windows and Vents: Ensure the deck height does not obstruct basement windows, vents, or other crucial components of your home’s exterior.
3. Access Points: Plan for how the deck will integrate with existing doors and entryways. This includes making sure doors open freely and considering steps or ramps for easy access.

Foundation and Structural Considerations

1. Type of Foundation: Determine the type of foundation your deck will need based on the soil conditions and local building codes. Options include concrete footings, piers, or floating deck blocks.
2. Height of Foundation: The height of your house’s foundation will affect the design of your deck. Ensure the deck’s height complements the existing structure and consider any necessary adjustments.
3. Securing to the House: Plan how the deck will attach to the house. The ledger board must be securely fastened to the house’s framing, not just the siding, to ensure stability and safety.

Regulatory and Practical Considerations

1. Local Building Codes: Research local building codes and permit requirements. This will ensure your deck is up to code and help you avoid fines or the need for costly modifications.
2. Utility Lines: Identify any utility lines (gas, water, electricity) in the area to avoid damaging them during construction. Contact your local utility companies if necessary.
3. Drainage and Water Management: Consider how water will drain off and away from your deck. Proper drainage is essential to prevent water damage and maintain the integrity of the structure.

By carefully considering these factors during the planning stage, you’ll set a solid foundation for a successful deck project.

Step 2: Setting Your Foundation

In this step, we will cover the entire process of setting your footings, starting from planning your post placement to digging and setting the concrete footings. A strong foundation is crucial for a durable and stable deck. Here’s how to get it right:

Planning Your Post Placement

1. Determine Beam Size and Span

• Beam Size: Understand what size your beams will be and their maximum span. This is essential to determine the placement of your posts.
• Deck Size and Beam Location: Depending on the size of your deck, plan where your beams will be located.

2. Post Placement Relative to the House

• Attached Deck (Flush Mount Beam): If your deck is attached to the house with a flush mount beam (where joists attach to the beam via hangers), the beam should be placed the full width of the deck minus the width of your fascia board (typically 1” for composite and 1 1/2” for pressure-treated or cedar).
• Free-Standing Deck (Flush Mount Beam): For a free-standing deck with flush mount beams, the beams need to be the total width minus the width of your fascia board times two.
• Under Mount Beam: With under mount beams (where joists rest on the beam), the beams should be the width of the deck minus your overhang (typically about 16”). For a free-standing deck, subtract the overhang times two.

3. Choosing the Right Beam Type

• Under Mount Beams: Ideal for beginners or DIYers as they do not require perfect squareness and straightness for footings.
• Flush Mount Beams: Allow your deck to be as close to the ground as possible, but require more precision in footing placement.

Laying Out Your Footings

1. Gather Materials

• Inverted marking paint
• Stakes
• String line
• Sledge hammer

2. Mark the Furthest Post Locations

• Start by marking the center of the two furthest post locations. Inset posts about 12” from the outside edge of the beam.

3. Square Off the House

• Use the wall of your house as a straight edge. Tie a string line to a far corner on a perpendicular wall and pull it out past the full size of your deck, ensuring it is straight with the wall.
• Use the string line and the wall as measuring points to ensure squareness.

4. Mark and Stake Posts

• Once the first post is marked, measure and mark the last post in the line.
• Insert stakes at these spots and tie a string line across. This provides a straight line for determining other post locations.
• Separate your posts so they end up on beam joints.

5. Squaring a Free-Standing Deck

• Use the 3-4-5 method: Measure 3 feet on one side of a triangle and 4 feet on another. Adjust the lines until the hypotenuse is 5 feet. This will give you a perfectly square corner.
• Continue this method until all posts are marked out.

Digging and Setting Footings

1. Digging Holes

• Use an auger or hand dig the appropriate-sized hole for the required-sized sono tube.
• Ensure to dig below the frost line (48” in Ontario).

2. Pouring Concrete

• Pour concrete into the holes and set the sono tubes to a similar height or perfectly level if mounting beams right on top.

By following these steps, you’ll set a strong and reliable foundation for your deck.

Step 3: Framing Your Deck

Framing is the backbone of your deck. A properly framed deck will be sturdy, durable, and safe.

Choosing Your Framing Material

1. Beam and Joist Size

• Beam Size: This should have been determined during the foundation stage. Ensure the beams can support the load and span of your deck.
• Joist Size: Refer to local building codes for deck joists. Determine the total span and choose the appropriate size. I recommend going up one size to eliminate any bounce or give in the deck.

Mounting Your Ledger Board

1. Attaching to the House

• Placement: Place the ledger board at the desired height, ensuring it is level.
• Over Siding: If attaching over siding, carefully remove the siding to attach directly to the studs or rim board. Use two lag bolts every 16”.
• Into Foundation: Use concrete lag bolts, alternating up and down every 12 inches to avoid compromising the concrete. Mark joist placements before placing lag bolts, leaving room for joists and joist hangers.

Setting Your Beams

1. Using Saddles

• Level Sono Tubes: If sono tubes are level and at the desired height, place the beams in a saddle that is lag bolted directly to the sono tubes.
• Raised Decks: For raised decks, if sono tubes are at ground height, lag bolt saddles to the tubes. Use shims if necessary to level. Place posts in the saddle, leaving them longer than the desired height, and secure with structural screws.

2. Finding Desired Height

• Flush Mount Beams: Measure the desired height by adding the deck board thickness to the beam height, then subtract this from the total deck height.
• Under Mount Beams: Measure by adding the deck board thickness, beam height, and joist height, then subtract from the total deck height. Use a level or laser to mark the rest.

3. Marking and Cutting Posts

• Mark one post and use a level or laser to mark the others. After marking, cut all posts to the desired height.

Mounting Beams

1. Beam Assembly

• One Ply at a Time: This method is lighter and easier if working alone.
• Pre-Assembled Beams: Assembling beams on the ground ensures each ply is perfectly flush. Nail every 16” using a pattern where a 2×4 needs two nails, a 2×6 needs three, and so on.

2. Securing Beams

• Ensure everything is level as you go. Some codes require hurricane ties from beam to post; others allow toe nails.

Placing Joists

1. Joist Spacing

• Centre Spacing: Joists should be at most 16” apart for 1” deck boards. Some deck boards require 12” centres—check installation requirements.
• Code Reference: Refer to the same code that provided your joist length for joist centres.

2. Marking Joists

• Consistent Marking: Pull all joist marks from one spot for consistency. If centres are 16”, mark the first one 15 1/4” with an X on the far side, then 31 1/4”, and so on. This ensures a 4’, 8’, 12’, or 16’ board ends exactly on the centre of a joist.
• Speed Square: Use a speed square to square the marks for precise joist placement.

3. Calculating Joist Length

• Ledger Board and Under Mount Beam: Total deck length minus 1 1/2” for the ledger board and the width of the fascia material.
• Between Flush Mount Beams: Total deck width minus the sum of the two beam widths.

4. Mounting Joists

• Flush Mount Beam: Toenail each joist into each ply of the beam, alternating sides.
• Ledger Board/Flush Mount Beam: Toenail in place. If the joist moves off the line while nailing, use a hammer to reposition. Install joist hangers using recommended nails.

Mounting Rim Board

1. Attaching Rim Board

• Hold the rim board in place at the end of the joists and nail it in place.

Adding Joist Tape

1. Applying Joist Tape

• Before placing the deck boards, apply joist tape to the tops of all joists and beams. This waterproof tape protects the wood from moisture and helps prevent rot, ensuring your deck lasts a lifetime.

By carefully planning and executing each step, you’ll achieve a beautiful, professional-looking deck surface that will last for years.

Step 4: Planning for Your Railings

Before installing your deck boards, plan for the type of railing you want. If you are installing wood posts for your railing, they need to be attached to the framing of the deck using structural screws.

1. Installing Wood Posts

• Attach the posts to the framing of the deck using structural screws.
• Ensure the posts are level and securely fastened, as they will provide the main support for your railings.

Step 5: Placing Your Deck Boards

Placing your deck boards is where your deck starts to take shape and show its true character. Proper planning and installation will ensure a beautiful, durable surface. Here’s a detailed guide to help you with this step:

Planning Your Deck Board Placement

1. Board Length and Layout

• Single Boards for Small Decks: If your deck is under 16’, you can use single boards that span the entire length of the deck. This not only simplifies installation but also enhances structural integrity.
• Using a Breaker Board: For decks longer than 16’ where a single joint is necessary, consider using a breaker board (a board placed perpendicular to the deck boards). This can hide joints effectively. To install a breaker board, add two joists, one on the center of each edge of the board.

2. Design Layout

• Design your deck board layout to suit your aesthetic preferences and functional needs. Whether you prefer a traditional straight layout, a diagonal pattern, or something more intricate, planning ahead will make the installation process smoother.

Choosing Fastening Systems

1. Composite Deck Boards

• Hidden Fastening Systems: Most composite deck boards come with their own hidden fastening systems, which provide a clean, fastener-free surface.

2. Pressure-Treated Lumber and Cedar

• Camo Screw System: For materials like pressure-treated lumber and cedar, I recommend the “Camo Screw” system. This system allows you to fasten deck boards from the side, hiding the screws and providing a clean look.

Installation Process

1. Preparing the Surface

• Ensure the joist tops are level and clear of debris.
• Check for any protruding nails or screws and address them before laying the boards.

2. Laying the First Board

• Start from the outer edge of the deck and work towards the house.
• Place the first board, ensuring it is straight and aligned with the deck’s edge.
• Use spacers to leave a small gap (about 1/8”) between the house and the first board for drainage and ventilation.

3. Fastening the Deck Boards

• Hidden Fastening System (Composite): Follow the manufacturer’s instructions for installing the hidden fasteners. Typically, you’ll place the clips in the groove of the board and screw them into the joists.
• Camo Screw System (Pressure-Treated/Cedar): Use the Camo tool to position the screws on the sides of the boards. This tool ensures uniform spacing and proper screw placement. Drive the screws in, making sure they are flush with the surface.

4. Continuing the Installation

• Lay the next board, using spacers to maintain even gaps between boards (typically 1/8” to 1/4” depending on the material).
• Secure each board using the chosen fastening system, ensuring they are straight and evenly spaced.
• If using a breaker board, ensure it is properly aligned and secured with the additional joists.

5. Trimming and Finishing

• Once all boards are installed, trim any overhanging ends to ensure a clean, uniform edge.
• Install any necessary trim or fascia boards to cover the exposed ends and enhance the deck’s appearance.

Step 6: Building Stairs

Building stairs is a critical component of your deck, providing safe and easy access. Properly planning and constructing your stairs will ensure they are both functional and durable. Here’s how to do it:

Choosing Stair Location and Size

1. Select Location

• Determine the best location for your stairs based on accessibility and aesthetics.
• Consider the available space and how the stairs will integrate with the deck and the surrounding area.

2. Calculate Total Height and Number of Stringers

• Measure the total height from the deck surface to the ground where the stairs will land.
• Based on the total width of your stairs, decide how many stringers you will need. Typically, stringers should be spaced no more than 16” apart.

Calculating Riser Height and Tread Depth

1. Riser Height

• Divide the total height of your stairs by a whole number that gives a riser height between 7” and 8.5”. This ensures a comfortable step height.
• For example, if your total rise is 42”, dividing by 6 steps gives you a riser height of 7”.

2. Tread Depth

• Building code usually requires a minimum tread depth of 10.25”. However, for added safety and comfort, you can make the treads deeper.
• If space allows, consider making the treads 3 deck boards deep (about 16.5” with proper spacing) or at least 2 deck boards deep (about 11.5”).

Marking and Cutting Stringers

1. Marking Stringers

• Use a framing square to mark your stringers. Place one finger on the total rise measurement and another on the total depth, minus any overhang.
• Trace out the steps on the side of the stringer, starting one riser where the last tread ended. Continue this pattern until you reach the desired number of steps.

2. Cutting the Bottom of the Stringer

• Ensure you cut the bottom of the stringer to remove the height of one deck board, as you won’t be applying deck boards to the ground.

3. Cutting Middle Stringers

• For middle stringers, cut a notch the size of a 2×6 where the stringer will rest against the deck.

Assembling the Stairs

1. Attach a 2×6 Support

• Attach a 2×6 inside the notched area of each middle stringer using nails. Then, nail the outside stringers to the edge of the 2×6.
• This provides a solid board to secure the stairs to the deck’s rim board.

2. Securing the Stairs

• Install the stringers at the height of the tread plus a deck board thickness down from the top of the fascia.
• Secure the 2×6 support to the deck’s rim board using structural screws or nails.

Adding Deck Boards and Finishing Touches

1. Adding Deck Boards

• Plan and place any needed posts for support.
• Attach deck boards to the stringers to form the treads. Ensure proper spacing for drainage and expansion.
• Consider adding a stringer cap that covers from the end of the nosing to the back of the stringer for a finished look.

2. Installing Risers

• Fill in the risers with appropriate material. Fence boards can be a cost-effective option compared to deck boards.

By carefully planning and following these steps, you’ll build sturdy, safe, and aesthetically pleasing stairs for your deck.