Collapsed deck
Photo by Thevanguard.ca

15 DIY deck mistakes not to make

Share This Story!

Building a deck seems like a simple project for someone who is reasonably comfortable with DIY—but there are a surprising number of mistakes to be made.

Here are our top 15—and how to avoid them.

1. Not having a design plan

Think about how you’re going to use your deck—for sitting? Eating? Cooking? Entertaining? All of those purposes require different types of spaces, and if you don’t take them into consideration, you’re going to have a big fat waste of time and money on your hands. Consider incorporating different “rooms” or areas for specific purposes: put the dinner table close to the barbecue, and consider creating a separate seating area.

2. Not thinking about the barbecue

You don’t want the barbecue miles from the back door, but you also don’t want it super close to your sitting area. It’s probably a good idea to figure out where it’s easiest to put the barbecue, and plan the rest of the space around that.

3. Not thinking about furniture

A full-on outdoor living room set with a gazebo is (obviously) going to take up a lot more room than two Muskoka chairs and a cooler. Consider building multiple levels if you want to have an elaborate seating area.

4. Not planning for the elements

If you’d like to enjoy your deck as much as possible, plan for both sun and rain shelter. Track where the sun shines at different times during the day, and plan accordingly.

5. Not getting a permit

Yes, you need a permit to build a deck if it’s going to be more than two feet off the ground. Sorry—but you don’t want to risk an unsafe deck.

6. Not investigating all your decking options

You can pick from classic pressure-treated lumber, composite, or hardwood. If you’re OK with regular maintenance, pressure-treated wood is a cost effective way to go. Composite and hardwood are more expensive, but require less maintenance. The choice is up to you.

7. Not having a handle on fasteners

Unless you want to deal with rust stains and worse, make sure the fasteners you use are appropriate for outdoor use. Stainless steel or coated fasteners are best for decks. Also, use the right fasteners for the job: don’t attach a guardrail with wood screws (they’re not strong enough), and don’t nail the deck to the ledger board (use through bolts or lag screws). When in doubt, make sure to follow any manufacturer’s instructions.

8. Not having appropriately sized structural members

Don’t try to save money by skimping on undersized joists and beams—make sure everything is the right size for the job. Also, factor in the weight of snow and ice when you’re calculating how much weight your deck will bear.

9. Not digging footings deep enough

In places with a freeze-thaw cycle (so, all of cottage country), concrete footings should be placed at least four feet below grade in a builder’s tube. Don’t be tempted by those convenient pre-formed concrete deck blocks—they won’t hold up to temperature fluctuations, leading to a heaving, sinking deck.

10. Blocking the view with the guardrail

If your deck is more than 30 inches off the ground, your railing needs to be at least three feet high. Unfortunately, that may be right at eye level when you’re sitting—which means your gorgeous view of the lake is suddenly obscured. Consider building the railing slightly higher to maintain the view.

11. Bolting beams to the sides of support posts

Nope. Beams should rest on top of support posts because there aren’t usually enough posts to support the weight of the deck.

12. Using an incorrect riser height for stairs

Riser height needs to be consistent (a maximum of 7.75”), but beware of your bottom step: often, inexperienced builders end up with a bottom step that’s taller than the rest, because they fail to factor in the lack of a tread (often an inch thick) at the bottom of the staircase.

13. Not attaching the deck to the house

Yes, it’s possible to construct a “floating” deck, but generally that means sinking footings into the dirt at the side of the cottage—which is considered “disturbed” soil, as it was displaced to build the building. Disturbed soil isn’t compacted enough to support the weight of a deck, so you end up with a much greater risk of sinking.

14. Not paying attention to emergency exits/clearance

If you have a basement window under your deck, be aware that it might represent a point of exit in case of an emergency, and blocking it will create a code violation. You also need to be aware of the location of your electrical panel, and not build too close to that.

15. Not sealing and maintaining a wood deck

Wood is lovely, but it needs to be protected from moisture if it’s going to stay that way. Make sure to seal your deck as a last step to enjoying it, then keep it clean and swept during the year.

What are your top DIY deck tips?

More from Cottage Life: