Choose your deck materials

Know your options before you design your new deck

By Canadian Home Workshop

deck

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Materials

Choosing the material for your new deck isn’t as simple as wood versus composite.

If solid wood is your preference, you can choose pressure-treated lumber, which is the most inexpensive material option. You have to get used to the green tint and carefully consider all your hardware, but this lumber is sure to last a few decades. You can also pick the classic look of cedar. It’s a great outdoor material, but it will cost you more money up front and on maintenance (especially refinishing). You could also discover the less used (but still hearty) options of alternative woods such as cypress and redwood.

Composite woods are a combination of recycled plastics and wood. The look of these boards has improved considerably over the years, but, upon close inspection, some builders still aren’t happy with the way these products attempt to mimic real wood. However, if low-maintenance–a quick power wash every spring is all you need–is appealing, then you need to decide on solid or hollow-core composite. Solids work like real wood and give you more design options (such as a routed edge) but hollow-core is lighter to work with and is often cheaper.

It’s important to note that while composites can be used only for the decking and rails, you’ll need solid wood for the entire support structure.

Find a balance between price, long-term maintenance and aesthetics.

Foundation

Put your best foot forward when designing a deck–literally. The feet or foundation of a deck is the starting point for success or failure. There are two main options: precast deck blocks or poured concrete piers.

Deck blocks are easy to install. They support the deck above grade with a firm base over your soil. However, if your soil is soft enough to allow the deck to shift, you’ll be sorry. Concrete bases work best with very low heights and small decks on light, well-drained soil that doesn’t heave seasonally.

Concrete piers take more effort, but, if they’re properly installed, they will support a deck without moving at all throughout its lifetime. This system involves holes dug to the frost line (check your local requirements) with concrete poured into tubular cardboard forms. For extra resistance to frost heaving, wrap the cardboard in black poly and add rebar to the concrete pier. To finish it off, add a post saddle to the top of the wet concrete.

For the posts themselves, 4x4s make for a sturdy structure; however, choosing 6x6s adds strength and visual presence to your deck.

Pick above- or below-grade footings based on your deck and soil.

Fasteners

The screws you use can make or break your DIY deck. Pick the wrong screws and you’ll either be sorry as you build (with lengths that are too short or too long) or very sorry later (with screws that corrode over time). These little wonders hold the whole project together, so consider all your options before you buy.

Narrow your search to screws made specifically for decks. They are made to drive smoothly into your deck materials. Next, look at what the fasteners are made of. If you are using pressure-treated lumber, you need the best screws. The strongest choice is stainless steel; however, these screws will add a lot to your budget. Look for screws rated safe for the ACQ chemicals used to make pressure-treated wood, including hot-dipped galvanized fasteners.

The right screw length depends on the thickness of your boards. Be sure the screw penetrates at least 1 1/2" into the joist below.

One final note: the Canadian-invented Robertson head is your best bet for great driver bit grip and torque.

From tip to tail, be sure your screws are compatible with your wood

Frame

When framing your deck, you first need to decide if it will be free-standing or attached to your house with a ledger board. Free-standing decks need support from posts on all sides, so more digging is involved. But if you can’t easily attach the deck to the house, this is a necessary step. However, with a ledger board, you gain strength from the house structure.

The ledger board runs along the side of the house. The board then connects to the deck frame. If your ledger board is attached to brick, you can prevent rot by using a wood spacer block so the board isn’t resting against the masonry. Or you can add a bead of clear caulking at the top to prevent water from getting behind the board. The ledger board is anchored with lag or masonry bolts that extend into the house frame by 1 1/2". Again, choose the right hardware based on your materials.

The same is true for another important piece of frame hardware: metal joist hangers. These make it easy to connect joists to the ledger board. Choose the right size of hanger based on the joist size (2x8 and 2x10 are the most popular) and use the right screw to fit the hanger holes. When laying out your joists, run them perpendicular to the house whenever possible. You also need to consider your joist spacing carefully. The centre-to-centre measurements for the joists should be between 16" and 12".  A strong skeleton is needed for a strong deck.

Rails and stairs

You’ve planned the basic structure, now you can work out some important details. The rails and stairs are not only necessary elements of a deck but also ones that need careful consideration for both safety and beauty.

Pick the railing height based on your local building code. The options for railing styles are almost endless. Between your deck posts, you can build simple balusters with upper and lower rails. (Watch your spacing between the balusters for safety.) Or to keep the view of your yard open, you can use glass panels framed by rails. Some details that you may want to consider are bevelled edges on the rail for drainage and caps for the post tops.

Cascading or simple­­–however you want your stairs to look–they must be designed for safety. Look to your local building code for the minimum/maximum sizes for treads and risers. Open risers are easier to build, but don’t have the same finished look and can be more dangerous. Build your stringers with wood or use plastic stair brackets that act as risers. The stringers must be properly attached to the landing with joist hangers and brackets.  Safety first, aesthetics next.

Finish

To protect your deck from water, dirt and sun, you need to think about the finish. (By the way, if you choose composite wood, you get to skip this section entirely.) Stains and sealers come in film-forming and penetrating formulas. The colour (or transparency) of the finish is up to you.

Film-forming finishes are popular choices. They’re known to peel over time, but with proper preparation (use a random-orbit sander before you begin), you can have a deck finish that lasts more than a few seasons.

Penetrating sealers seep deeply into the wood to protect it. These formulas are less likely to peel; however, some types are prone to mould growth.

Sometimes you get what you pay for, and many believe this is true for deck finishes. Research different brands by asking your friends about their deck successes. As well, review independent testing results, such as those by Consumer Reports magazine.

Plan this final stage with as much care as the construction.

Dress it up!

When designing your deck, you may want to add features that enhance your outdoor living space. Some additions you may want to consider:

- a pergola

- built-in benches

- planter boxes

- latticed privacy wall

- stairway lighting

- outdoor speakers


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