One of the most important things to know before starting your deck building is how your client wants to use the space. This will help you plan the layout and design.
Local setbacks and permit requirements will also play a role in your plans. For instance, if you’re planning to build on concrete deck blocks, a good layer of insulation can help prevent frost heave. Contact Deck Builders Franklin TN for professional help.
A deck’s frame and joists distribute its weight to prevent it from buckling or collapsing. The substructure’s construction and joist spacing depend on your specific deck layout and building materials. Deck components are vulnerable to moisture damage and weathering, which requires routine inspections and maintenance.
Beams, also called girders, transfer load from joists to posts, keeping the structure stable. They’re typically constructed from wood, but can be made of other material as well. They’re usually square or rectangular in cross section, but can be a variety of shapes to increase their structural efficiency. For example, a lattice beam’s web has diagonal pieces that form a lattice-like pattern to resist compression and bending loads.
When you build a deck, you’ll need to choose the right lumber for its frame and joists. Pressure treated lumber is typically the most economical option, but you may want to use other species for your decking or railing. Be sure to consult a span table for your particular material, and check local building codes for any specific requirements that your project may require.
To avoid mistakes during framing, be sure to plan for expansion gaps and proper mitered cuts. If you fail to take these factors into consideration, you could experience warping or rotting over time. It’s also important to fasten joists securely, using both nails and screws that are hot dipped galvanized or stainless steel. This helps prevent moisture infiltration, which can cause the joists to twist or even collapse over time.
Joists
Joists and beams work together to distribute weight evenly and provide strong support for your deck surface. They also play a critical role in determining how long your deck will last, so it’s important to choose the right materials and use proper installation techniques.
Floor joists are typically 2×6 through 2×10 pressure-treated lumber, while ceiling joists are 2×12 or 2×14. The size of the joists you use will depend on your project’s design and load specifications. Use a joist span table to determine the appropriate size for your deck. When selecting joists, keep in mind that longer spans require wider and thicker joists.
Wood floor joists are common in residential construction, but can require sealing or treatment to resist moisture and pest infestation. Engineered joists like laminated veneer lumber (LVL) or oriented strand board (OSB) offer greater strength, durability, and versatility, with the ability to span large distances while remaining lightweight.
In timber frame construction, there may be a single set of joists that carry both the floor and ceiling called a single framed floor. Or, joists that support both the floor and ceiling are called double-framed floors. The binding joist that supports the ridge beam in a gable roof is called a bridging joist.
Before securing your joists, make sure that the framing layout is square. Run a string between the ledger and batter boards, then adjust the ledger-to-batterboard strings until they match exactly. This will help prevent the structure from sagging or warping over time. Once the deck joists are in place, secure them with post-to-beam connectors or metal brackets. Make sure to use a waterproof sealant to protect the connection. This will prevent rot and water infiltration, as well as protect the joists from the elements.
Footings
Footings are how a deck connects to the ground, and they’re key to keeping it safe and secure over time. By distributing the weight of the deck across a wider surface, footings protect against sinking or shifting. They’re also designed to withstand the forces of the soil, such as freeze-thaw cycles and other environmental factors. The type of footing you choose depends on the site conditions and expected load, as well as local building code requirements.
Most footings are made from concrete, which can be poured in place or precast and stacked. Poured concrete footings require careful planning and execution to ensure a strong, stable foundation. To begin, clear the area and dig holes that are the correct size and depth for your deck. Mix the concrete to the recommended consistency and add reinforcing steel if necessary. After pouring, use a post-hole digger or tamper to help settle the concrete. Most jurisdictions require a building inspector to review the footing holes before they’re filled.
Before installing your deck, consult with a utility locator service to verify that you won’t be drilling into any buried public utilities. This will save you the cost and hassle of digging up and replacing damaged utility lines down the line.
If you prefer to avoid the labor-intensive process of pouring concrete, a deck pier or screw pile footing might be a better option for you. These are large concrete structures that extend further into the soil than regular footings, and they’re a good choice for heavy loads or challenging site conditions. However, they may not provide the strength you need to build a large deck. If you’re building a larger deck, talk to a professional about your options for footings.
Support Posts
Posts, or columns (the same thing), are the vertical elements that support your deck’s frame and transfer load to the footings below. Like the joists, they are critical components that should not be neglected. When a deck’s posts fail, the whole structure can collapse. In general, a post will fail if it becomes unsupported by its bearing elements — a joist or girder — or if the compression on its sides exceeds its capacity.
A deck builder can help you understand the load calculations that determine how big a post must be and how many to use. They’ll also help you decide if 4×4 or 6×6 posts are best for your design. Both are acceptable, but 6×6 posts are more cost-effective and provide greater stability.
Wooden support posts are common and work well on most decks, but steel structural posts are also a popular choice. These are more commonly found in newer homes, but some older houses still have wooden support posts. Regardless of what type of posts you choose, they need to be sized and placed correctly to prevent failure.
Home inspectors can spot signs of failed deck posts by using a post level to check if they’re plumb (level). A damaged or cracked post should be repaired as soon as possible, since cracking that extends beyond the diameter of the post is a clear indicator that it won’t hold up to a heavy load for long.
If a damaged support post is surrounded by termite damage, that’s another indication of an issue that may require professional repairs or replacement. Likewise, if a post has rust stains on its exposed side, it indicates that the post has not been properly resurfaced and is no longer rated for permanent use. A professional should examine the extent of any rust damage to determine whether it’s enough to compromise the strength of the post and should be replaced.
Piers
Piers are used to support the joists and beams of a deck and are a crucial part of its construction. They must be strong enough to handle the weight of a deck and its inhabitants, as well as the weather elements such as wind, snow, and ice. If a deck’s support is not sufficiently robust, it could become unstable or collapse. Fortunately, there are several ways to ensure the piers of a new deck are sturdy and robust.
One option is to use deck pier blocks. These are pre-formed deck foundation blocks that are typically made of concrete or a highly durable plastic. They come with holes that can be used to attach the piers of a deck. This makes them easier to install than traditional footings and can help you avoid the cost and hassle of digging and pouring footings.
In addition, pier blocks provide an effective way to support posts in situations where the ground is not suitable for other foundation types such as buried post footings or helical piers. These conditions commonly include soft soils that require wide footing holes, or areas that experience a high amount of freeze-thaw cycles. For these reasons, a deck built on piers is often more stable and long-lasting than a deck supported by other types of foundations.
Deck pier blocks are also an excellent option when working in tight spaces where it is difficult to fit heavy equipment such as a crane. In addition, pier blocks can be used for freestanding or floating decks that are low to the ground, as well as for homes with a large number of levels or very heavy loads. However, it is important to note that pier blocks are not as durable or as long-lasting as footings, and they may not comply with local building codes.
