Reno Expert: Solid Structure

Reno Expert: Solid Structure

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Reno Expert: Solid Structure

by Jim Caruk

The Do’s and Don’ts of Deck Building

If you’ve ever flown to Florida or southern California, you’ve probably noticed how many suburban backyards are dotted with pools. Here in Ontario, the recurring backyard theme is a deck. Whether they’re clad in natural wood or a composite product such as Trex, decks are outdoor extensions of our household living space. Many are simply a place to park the barbecue and a patio table but, increasingly, they’re loaded with bells and whistles that literally include a kitchen sink.

Since (most) decks don’t involve any wiring, plumbing, or overly complicated structural elements, building one is something a lot of DIYers are willing to tackle. But there are a number of common mistakes they make.

Generally speaking, if your deck meets any or all of the following conditions, you’ll need a permit:

a) The deck will be attached directly to the house

b) Will have a surface area of more than 100 sq.ft., or

c) The top of the deck boards will be two feet or more off the ground.

As part of your permit application, you’ll need to include your property survey and a drawing showing where the proposed deck will go.

Here are three key areas where DIYers—and some unqualified pros— make mistakes when building a deck.

Photography courtesy of Trex
Photography courtesy of Trex


If the top of your deck boards are two-feet or more off the ground, you’ll need a railing that’s at least 3′ high around the perimeter. (If the deck is 6′ or more above grade, the railing will need to be at least 3’6″ high.)

The gap between the vertical slats— or pickets—has to be less than four inches. The idea here is to prevent a small child from squeezing through and getting stuck.

Another option is to use glass panels. These cost more than lumber would but give you an unobstructed view of the yard.

Built-in seating along the railing can be a great way to maximize space, but keep in mind that a building inspector will measure the railing height from the top of the seats. After all, the main point behind these rules is to avoid having a child—or perhaps tipsy adult—topple over the side and get hurt.


Again, if the deck is more than two feet off the ground, you’ll need stairs with a railing that meets the above-mentioned guidelines. The stairs themselves must be between 47/8″ and 77/8″ high, and 91/4″ and 14″ deep. The key to building stairs is that each one has to be the same height and depth as all the others. If not, you’ll find yourself stumbling on any that are out of line with the others.


Even if you’re using a composite material such as Trex for your deck boards and railings, you’ll likely use natural wood for the framing. Typically, that means using pressure-treated (PT) lumber. But the chemicals used to make the wood rot- and insect-resistant can be corrosive to most building hardware. Make sure you use PT-approved screws and hangers. Also note that any framing members must be attached with nails, not screws. Screws do not have the sheer strength to support the load properly.

Jim Caruk, Renovation Editor

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