Why Every Deck Needs an Annual Inspection

Learn why decks fail and what you can do to keep your family safe

Birthday parties, graduation celebrations, family barbecues – no matter what your summer plans include, chances are many of those festivities will take place on your deck. May is Deck Safety Month®, so before you plan any seasonal fun, take some time to ensure your outdoor space is safe and structurally sound.

Age, exposure, and the shortcomings of wood can lead to problems

According to recent statistics from the North American Deck and Railing Association (NADRA), more than 40 million decks in the United States are 20+ years old. Building codes, construction methods, and decking materials have changed considerably in the last two decades. Plus, since decks are outdoor structures, they are always at the mercy of weather and extreme temperature fluctuations which, over time, can lead to structural breakdowns.


Even the most beautifully built Fiberon decks need an annual inspection.

But what if your deck isn’t that old, or it’s a long-lasting Fiberon composite deck? Even so, the substructure likely is wood, and wood rot is one of the main culprits responsible for deck failures (a term used to describe any deck or railing failure that leads to injury or total deck collapse). Ledger board issues are another concern.

Proper ledger board installation is essential

The ledger board is the piece of lumber that runs parallel to the edge of the house, attaching the deck to the house. 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 – and with the correct fasteners – to avoid deck collapse.


The ledger board bears about one-half of the deck’s weight. Proper installation is essential. (Image credit: decks.com)

Never attach a ledger board with nails. The weight of people and objects on a deck, coupled with movement, creates vertical and horizontal forces. As the weight shifts during normal activity (for example, people milling about during a deck party or children running across the space), the nails are 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 how nails might pop out of the ledger board. For these reasons, deck tension hardware (structural screws, bolts, or tension ties) should always be used, and in accordance with local building codes and construction best practices.


Water: the number one enemy of wood

Another cause of deck failure is wood rot. This usually results from the wood’s being exposed to water due to improperly installed (or missing) flashing. When the moisture content in wood reaches 19%, wood rot (which is actually a fungus) goes to work. The damage, however, isn’t always visible at first – yet another reason to do an annual deck inspection!


Five Things You Can Do to Keep Your Deck Safe

NADRA provides a listing of qualified deck inspection members who must comply with state licensing and insurance requirements as well as adhere to a code of ethics (visit www.nadra.org for more information).

Another great resource from NADRA: their Check Your Deck® Consumer Checklist. This informative 10-point guide covers everything from locating wood rot to trimming tree limbs. We’ve summarized some key points below.


1. Inspect the wood
  • Inspect several areas of your deck to ensure the wood is still sound; among them:
    • The ledger board
    • Support posts and joists beneath the deck
    • Deck boards, railing, and stairs – unless you have decay-resistant composite decking
  • Look for small holes in the wood or evidence of sawdust/wood dust. If any are present, it may be an indication of insect infestation.
  • Examine any areas that are regularly exposed to water, tend to remain damp, or are in regular contact with fasteners. If you can easily penetrate the wood or if the wood is soft and spongy, you might have wood decay.
2. Don’t forget the flashing
  • Proper installation of ledger board flashing is critical, say decking experts.
  • Flashing works to prevent moisture and debris from collecting between the house and the ledger board.
  • Flashing must be installed behind the siding and over the top of the ledger board.
  • Flashing should run the entire length of the ledger board and be free of any nail or screw holes.
  • If you notice water collecting anywhere, add flashing or replace what’s already there.
3. Check your fasteners
  • If you have wood decking, check for popped nails and pound them down or replace them.
  • Tighten any loose screws.
  • Replace rusted or corroded fasteners, as the corrosion can deteriorate any surrounding wood.
4. Remember the railing
  • More than a style statement, deck railing is about safety. In fact, more injuries result from rail failure than complete deck collapse, reports the International Association of Certified Home Inspectors (InterNACHI).
  • Push on your railing to ensure it doesn’t “give” in any way.
  • Ensure your rail complies with local building codes. That means a rail height of 36,” as per the International Residential Code (IRC), although 42” is required in some states and for commercial applications, which are regulated under the International Building Code (IBC).
  • Measure the spacing between balusters. To prevent small children and pets from squeezing through, the distance between each baluster cannot exceed 4” for line sections and 4-3/8” for stairs. In addition, the “triangle” created by the stair tread, riser, and guardrail cannot be large enough to allow a 6” sphere to pass through. (Tip: Always consult local building codes for the most up-to-date information.)
5. Light it up, safely
  • All electrical outlets, appliances and features must be code-compliant, childproof (if you have children or young visitors), and in good condition.
  • If electrical cords are present on the deck, ensure they do not present a tripping hazard.


The bottom line: safety first. Take the time to inspect your deck and make needed repairs, or contact a qualified inspector or contractor for help. No matter how well-built your deck, an annual check-up is always in order.

Peace of mind comes from knowing your deck is well-built and inspected regularly.

Of course, if you’re fed up with rotting wood, nail pops, and splinters, and are considering a replacement deck, take a look at Fiberon composite decking. Start planning your dream outdoor space today with our Outdoor Living Visualizer.



Editor’s Note: This post was originally published 5/23/2016 and has been updated for accuracy and comprehensiveness.