Although exterior deck framing is a type of general framing or platform framing, deck framing differs from other types of framing and should be treated as a distinct form of framing. Someone who excels at wall framing or roof framing is not automatically going to excel at deck framing because there are different structure and safety considerations that need to be made in the process.
Importance of Deck Framing
Beneath the decorative elements of the deck, the shaped flooring, railings, stairs and banisters, you have a basic frame skeleton that serves a very important purpose. The structure of the deck, the part that involves deck framing, is vitally
essential in ensuring that your deck is strong and safe, properly attached the home and capable of standing on its own. There is no single type or style of deck, and the type of deck that you decide to build is going to impact how you go about framing or structuring the deck during construction. To put things simply, the deck’s frame is its foundation. Just as a home or commercial building requires a strong and sturdy foundation, so does a deck. This applies regardless of whether the deck is on ground level or suspended above the ground on legs, because the deck frame is what everything else is attached to.
Tools and Materials for Deck Framing
Some of the basic tools that you will need for a deck framing job include:
- 2x2s and 1x4s
- Adjustable Wrench
- Black Polyethylene
- Chalk Line
- Deck Boards
- Framing Square
- Galvanized Box Nails
- Hex Bolts, Nuts, Washers
- Lag Screws
- Level and Line Level
- Mason’s Line
- Measuring Tape
- Plumb Bob
- Railing Material
- Ready-mixed Concrete
- Structural Connectors
You may not need all of these materials, but having them on hand is definitely a good start. You will not want to stop in the middle of your project because you forgot a basic tool or material, but you can always return extra materials to the hardware store if you end up with something you do not need.
Mounting and Flashing
Decks secured to the home, above ground level must be properly secured and flashed. Conventionally people have simply bolted the ledger to the wall framing, which is time consuming and which is neither resistant to rot or weather tight. Heavy duty aluminum brackets, therefore, come highly recommended because you can bolt them directly to shingles and rim joists. You want the attachment point for the bracket to be as solid and as weather tight as humanly possible for the deck framing to be sturdy and solid for many years.
Choosing Materials and Sizing Lumber
Most of the materials that you buy and prepare for deck framing are going to be the same from project to project. How you decide to size and shape your deck is going to influence some of the decisions that you make, however. For example, the type of lumber that you choose for your deck is going to influence what options are available to you. Choosing pressure treated lumber means you can select 5/4×6 decking or 2″ decking, and the species that you choose will also influence the spacing between the joists that you install as part of your deck framing process. For example, if you’re using southern pine, you’ll want 16″ spacing maximum. On the other hand, if you are using a thick redwood, Northern white cedar or Western red cedar, then you can space joists as far as 24″ at a maximum, though 16″ is still recommended.
It is important that you figure all of these details out first when you are planning your deck, before you begin building anything. The reason is because these fine details can go far in ensuring that your deck framing is as safe and secure as it possibly can be. Figure all of the details out first, put your plan down on paper, and then begin amassing the materials that you need for the finished product. Check your materials to your plan, make sure you have everything in order, and then and only then should you begin the building process.
Building the Exterior Deck Frame
Before the deck framing begins, the ground beneath the deck has to be prepared by removing all sod from the area. The ground should be sloped away from the property to which the deck will be attached by one inch at a minimum for every 15 feet, which will provide adequate drainage. The ground beneath the deck needs to be covered using black polyethylene in order to prevent plants or weeds from growing up into the deck frame.
The next step is to measure the position for the ledger against the building, with the ledger height being an inch below the door’s bottom plus the deck’s planned thickness and the depth of any joists if joists are going to be set on beams and ledger instead of on joist hangers. How you set your joists is ultimately up to you, but your layout needs to be consistent in order for your deck frame to be sturdy.
You can mount the lender to the wall using lag screws, taking care to make sure that the ledger is completely level, and that the lag screws penetrate into the wall studs by at least 3 inches. After you install the ledger, you can work on the layout of the deck frame. To establish the deck’s outside perimeter, measure out 18 inches beyond the deck’s outside edge beginning at the ledger, setting up batterboards and taut strings from each of the ledger ends to the batterboards, establishing the deck sides.
Now run strings between the batterboards, establishing the deck’s outside edges. Square the entire layout by measuring from diagonal to diagonal, and then adjusting the strings that run from ledger to the batterboards until both of the measurements are equal. Make sure that the correct distance is measured between all the strings.