Looking to add a deck to your home? A deck gives you a beautiful, functional outdoor living space where you can enjoy the great outdoors without leaving behind all the comforts of home. But who is going to build your deck? Do you hesitate between hiring a contractor and building your deck by yourself?
DIY-ing your deck will save you on labor costs, but it also may influence certain factors of your build based on your carpentry experience and time constraints.
Working with a contractor will add to your overall deck costs, but a contractor’s skillset and equipment better ensure your deck will meet your needs and aesthetic preferences — and is built up to code, and will last for decades.
If you want to build your deck yourself, here is some deck-building tips. Scroll down to see the basics of deck construction. So, let's start with the deck footings.
Deck Footing
* If you plan to build a free-standing ground-level deck to cover cracked concrete slabs or poorly growing grass areas, you will most likely use deck blocks or concrete slabs/pads to support your low-level deck. Deck blocks are precast concrete blocks that have a recessed area on top to hold a wooden post or beam. The blocks can be placed on a concrete pad or a compacted gravel base. It's the cheapest and easiest deck footing solution to build a ground-level deck with no holes to dig and no concrete to mix. One of the biggest problems with deck blocks they cannot resist side-to-side forces or frost heave, the seasonal movements may make your deck sloped or uneven. If you’re unconcerned about your ground-level deck moving a little, then deck blocks are probably for you. But, if you plan to build a raised deck or if you want to build a deck that you can leave to your kids, then you should use a buried foundation.
* If you plan to build a raised deck, using deck blocks as a deck footing for a raised deck is not recommended. Without a reliable deck footing/foundation, your deck may not be safe and may need permanent repairs. Please see the photo below.
The best type of general-purpose deck foundation uses thick cardboard tubes sunk into dug holes that extend below the frost line and are filled with concrete. Wooden posts sit on top of these piers, anchored with metal post saddles set into the wet concrete. Installing this system requires more skills and is more expensive than deck blocks, but poured concrete footings reduce the risk of movement and foundation failure to almost nothing if you put them in right.
* It's important to note that your local building codes may have specific requirements for deck footings, including depth and size, so it's important to check with your local building department before proceeding with any alternative footing system.
Post-to-Beam Connections
* Solid beam or multi-ply beam. Multi-ply beam it's 3 or 4 boards clamped by clamps and screwed or nailed together. The strength of a multi-ply beam is created by its rigid connection to one another. The solid or multi-ply beam must be placed on top of the post and secured with galvanized steel connectors (see picture below).
* If your deck is designed to have a double-board beam (double beam), you will have to notch a cavity into the tops of support posts to set the beams using galvanized carriage bolt fasteners to secure this connection.
* Never apply two boards on either side of a post as a beam in the "sandwich beam" style. "Sandwich beam" is prohibited in the construction of a deck. The post-to-beam connection is one of the most critical connections in the raised deck structure. So, if you hire a contractor and you see him installing one of the main deck beams using a "sandwich-beam" connection, fire him. It means he doesn't know or doesn't care what he does.
Ledger Board
* If you plan to attach your deck to the house, you will have to install a ledger board on the house wall. The ledger board transfers roughly half of the weight of the deck and the live load on the deck to the framing of the house wall that is supported by the building's foundation. The other half of the deck loads are supported by a beam, posts, and footings along the outside edge of the deck.
* Do research to understand what is the best way to connect/install a ledger board to your house wall. Factors like the type of wall cladding/siding and house wall structure may change the ledger board installation technique/way.
Joists
* A deck joist is a repeated board used as the structural base for your deck frame that is attached to the ledger via galvanized joist hangers. Typically, joists run perpendicular to the house wall, while the decking on top runs parallel to the house wall. In North America, joist spacing for residential decks is a maximum of 16" on center spacing for straight decking and 12" on center joist spacing for 45-degree angle diagonal decking.
* The deck beam and joists’ design is based on spacing, size and span length. Check with your local building codes to determine joist size and length. If you prefer to check for the joist span table/guide online, I'd recommend seeing the "Residential Exterior Wood Deck Span Guide" published in 2016 by the Canadian Wood Council.
Blocking
* Solid blocking should be installed between joists to further reinforce the strength of the structure and prevent joists from moving in service. As a minimum requirement, all joists with a span of more than 8 feet shall be blocked at mid-span. Deeper decks with 2 or more beams/spans will need blocking above beams and mid-span blocking if the distance between beams is more than 8 feet. Solid blocking is highly recommended if you plan to install traditional wood decking and is mandatory for composite, PVC, and other artificial decking.
Cantilever Or Overhang
* The cantilever is the overhang of the deck beyond the supporting beam. A cantilever is a part of the joist that is attached to the ledger board and then overhangs a beam to achieve a larger platform without moving the posts. So, what is the maximum allowable cantilever for your deck? According to the Canadian Wood Council Guide maximum allowable cantilever is 16" for 2x6/2x8 joists and 24" for 2x10/2x12 joists. The overhang dimension shall never exceed one-fourth of the actual joist span. The cantilever/overhang length shall be included in the total joist span.
* Where railings/guards are required, deck joists shall be a minimum of a nominal 2x8, double 2x8 deck perimeter in perfect conditions.
If You Cut It, Seal It!
Don't take shortcuts – treat your cuts!
You must apply the wood preservative solution on every cut you make in pressure-treated wood. Remember, Mother Nature doesn't accept excuses, so your exposed (unsealed) wood edges can begin to rot in the next few years.
Cut-N-Seal is a water-based, color-matched brush-on wood preservative for cuts and holes in pressure-treated wood that protects exposed untreated wood against rot and decay in above-ground applications.
The Cut-N-Seal is available in brown and green colors.
Important To Remember
* Before starting your deck-building project, check with your local building codes, regulations and zoning restrictions. Or, simply hire a deck-building pro.
* Your deck footings, posts with beams and ledger board are the foundation on which you’ll build your deck, they provide the structural support for your joists, decking boards and people on the deck. So, please take their installation very seriously and responsibly.
* Ignoring basic deck-building rules may lead to, at best, your deck will be springy, and at worst, at some future point, your deck will collapse in the middle of a party.
