Everything you need to know about deck/balcony safety and maintenance

Don’t take deck/balcony safety for granted. Here is a list of items to check each year before risking your family’s well-being. Safety first!

Split or decaying wood

Check several different areas of the deck/balcony to be sure the wood structure is still sound. This includes the ledger board (where it attaches to the home or building – a very common source of deck failure), support posts and joists underneath deck boards, railings and stairs.  Pay special attention to any areas that tend to remain damp, are regularly exposed to water, or are in contact with fasteners, where water can enter.  Use a tool like an awl or a screwdriver to penetrate the wood surface.  If you can easily penetrate ¼ – ½ inch, break off a piece without splinters, or the wood is obviously soft and spongy, decay may well be present and it can be unsafe.  This is also a good time to look for small holes in the wood, which can indicate insects and resulting damage.

Cracked concrete

Check several different areas of the deck/balcony to be sure the structure is still sound. This includes cracking (where the slab is now more than just 1 piece), which can allow decay and also water-ingress to the interior.  Be sure to check for cracking on the underside of the balcony above you as well.


Flashing is a metal or plastic guard that directs water out and away from vulnerable areas.  It’s often installed where the deck and house come together, keeping moisture and debris from collecting between the house and the deck’s ledger board.  Be certain the flashing is sound and firmly in place.  Consider adding or replacing flashings if you notice areas that are obviously allowing water to collect and/or enter.

Loose or corroded fasteners

Fasteners include nails, screws or anchors in the assembly.  Tighten any loose fasteners, and reset any nails or screws that have popped up.  If a fastener appears rusted or corroded, replace it.  A corroded fastener can cause deterioration in surrounding wood and can also fail under stress.  Approximately 90% of deck collapses occur as a result of the separation of the home and the deck ledger board.  Usually, the first board installed, the ledger board supports one end of the deck joists and bears about one-half of the deck’s weight.  The board must be the same material and size as the rest of the joists and it is must be attached firmly – with the correct fasteners – to avoid a collapse.

Ledger Boards

Never attach a ledger board with just nails.  The weight of people and objects on a deck/balcony, coupled with their movement, creates vertical and horizontal forces.  As the weight shifts during normal activity (imagine people on a deck during a party, or your children running across the space), the nails are steadily pried away from the ledger, bit by bit.

Add in the fact that wood will contract and expand as temperatures and humidity levels change and it’s easy to understand why the nails might pop right out of the ledger board.  For these reasons, deck tension hardware (structural screws, bolts and/or tension ties) should always be used – and in accordance with local building codes and construction best practices.

Improper Joist hangers

Joist hangers are the metal brackets that attach the deck joists to the home and the ledger.  The manufacturers of joist hangers are very specific about how they must be installed; they specify exactly which fasteners should be installed and exactly how much weight the joist hangers will support when installed properly.  Here are a few defects we regularly find with joist hangers:

  • Missing nails.  Nails are supposed to be installed into every hole.
  • Improper joist hanger nails.  We find improper fasteners on almost every deck.
  • Screws used instead of nails.  Screws don’t have nearly the shear strength of nails and they’re not an acceptable substitute – unless actually specified.
  •  Altered joist hangers.  Joist hangers shouldn’t be bent or cut.


The deck/balcony and/or related stair surfaces should appear even, without sagging and should not sway or move when tested with weight applied.

Railings and banisters

These should obviously be really secure.  Push on them to be sure there is no give.  Also, ensure they are high enough (most codes require a 36” high railing and usually encourage 42” high railings) with spindles no more than 4” inches apart (measured from inside) to keep small children and pets from squeezing through. This is especially important the higher you are off the ground. Railing spindles simply tacked or stapled on the outside are easily removed and can fall away, resulting in very dangerous conditions.


Check all railings or handrails to be sure they are firmly in place; check also the risers and stringers to be certain they are securely attached and not decayed.  If the area behind the stair treads is open, this opening should also be no more than 4” high.  Additionally, always keep stair pathways clear of planters, décor, toys and other items that can present a tripping hazard.

Cleaning and maintenance

Clean away any leaves and debris, since these can be slippery and promote mildew, as well as hold water from draining off.  Drains are also easily blocked, which can cause water ingress. If mildew is present or the deck coating has worn away, make time to clean and apply a new waterproofing coating /sealer.  It can help prevent the split, decayed wood and loosened fasteners mentioned earlier.

Grills, fire pits, chimneys, heaters and candles

These features can create a warm and cozy deck atmosphere, but make sure any source of fire or heat is safely placed away from any flammable surfaces or material.  Always use caution and follow manufacturers’ directions.

Lighting and electrical

If you don’t have adequate lighting, there are lots of great new deck lighting products you could consider to illuminate your steps and pathways.

Be sure all electrical outlets, appliances and features are up to code, in good condition and childproof. Watch that any electrical cords do not present a tripping hazard.  These should never be easily accessed. GFCI-protection is always a recommendation – if not already present.

Outdoor Furniture and Storage

Test all outdoor furniture to be sure it is sturdy.  Avoid placing seating right at the edge of the deck – for obvious reasons.  If you have a swing or hammock installed, test the system to be sure all is secure.  Consider installing childproof latches on any storage boxes and benches.  Be sure to keep all deck-related chemical products stored safely away from children, including BBQ lighter fluids, matches, cleaners, etc.

Surrounding trees

If you have trees overhanging your deck/balcony, make certain there is no danger of decaying limbs breaking free and falling from trees surrounding it. Large trees can also shade building elements and allow wood-rot to get underway, as the exterior cannot dry adequately between rain events.

About Glenn Duxbury

Duxbury & Associates Building Inspection and Consulting Ltd. has received the 2004 Douglas College Entrepreneur of the Year Award in the ‘Consulting’ category for persistence and pursuit of excellent service delivery to clients by providing very thorough and professional Inspection Reports and dedication to those involved in buying / selling / building / renovating and maintaining uncompromised customer focus.