A gorgeous deck in the backyard is a place to relax with family and friends. Occasionally, though, you’ve heard news stories about elevated decks collapsing and injuring people. How can you ensure that your deck stays safe, or build a new one that is trustworthy? Here’s our guide to safe construction and deck maintenance.
Anatomy of a deck
Perhaps the most important part of the deck is the ledger board. This is the floor joist that attaches directly to the house and anchors the entire deck structure. The ledger board should be constructed with 2” x 8” beams, or 2” x 10” for larger decks capable of holding heavier loads. The bolts holding the ledger board to the house should penetrate deeply into the slab. If the house is attached to piers and beams or a basement, the bolts should penetrate outside masonry and the floor joists of the house.
The perimeter of the deck, called the rim or band, consists of outer floor joists matching the width and thickness of the ledger board. Joists resting on support posts should be built up by nailing or bolting together two or three beams. Floor joists not resting on posts can be a single beam.
Joists should be buttressed between one another with short blocking beams. Decks should have a row of blocking every eight feet. Each end of the floor joists should be attached to the ledger board and to the band perimeter with metal hangers appropriate for the height of the beams.
Deck support posts should either be cemented down 18 inches into the ground or seated on concrete footers on the ground.
Finally, the deck boards that create the floor should be nailed to, or preferably screwed down into, the joists. Railing and steps to the ground are attached to the band.
Permits and inspections
If you intend to build a new deck, it is vital that you get the proper permits from your local municipality. Your contractor will submit plans for approval, and an inspector from the city will check that it meets safe construction standards. Building without proper permits risks an unsafe deck, fines if your structure is found non-compliant, and complications selling the house later.
Deck maintenance for longevity
The average deck is built to last about 20 years. But proper deck maintenance requires you to inspect it every three to four years, or have a professional deck contractor check it.
If you opt to do your own deck maintenance, be sure to do the following when you inspect the deck.
- Grab various places and shake to check for loosened support: railings, the band around the perimeter of the deck, the support posts beneath and the stairs. Inspect support posts to ensure that they have not shifted or are no longer plumb (straight up and down).
- After rainfalls, look for places where water stands, especially against the house. Install flashing above the ledger board to prevent water from penetrating the house.
- Look for screws, nails, or bolts that have worked loose or are unstable in the wood. This indicates rot has weakened the wood. You can also check for rot by using a screwdriver to poke the wood around connecting points: the bolts through the ledger board, the hangers at each end of the joists, the blocking perpendicular to the floor joists. If you can easily sink the point of the screwdriver into the wood more than 1/16 of an inch, the wood may have rotted.
- Check to see if termites or carpenter ants have damaged the deck’s wood. Though a deck may have treated wood for the joists or posts, these wood-destroying insects may cross them to attack non-treated wood.
If you find joists that are soft because they have rotted or insects have damaged them, you will need to replace them. Make sure to screw or bolt them in securely.
One deck maintenance step that will protect wood is to clean, strip and restain or paint the deck at least every five years. Or apply a clear finish each year.
Other safety tips
- Wood is the best non-slip flooring material for a deck, followed by aluminum. Composite flooring and plastic offer less slip protection. Adding area rugs with non-slip undersides provide an extra layer of safety.
- Include lighting on deck stairs for safe nighttime navigation. Some cities’ construction codes require this. Be sure the lights are rated for outdoor use under wet conditions.
- Place grills on fire-resistant grill mats, away from the home’s eaves, tree limbs or umbrellas.
- If your deck is low to the ground, shine a light underneath it occasionally to check for possums, feral cats or other creatures that may have made a home there. Call animal control if you find a squatter living there.
Related – Keeping Your Wood Deck Beautiful