How to Avoid Deck Collapse
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How to Avoid Deck Collapse

Updated: May 11, 2022


May is Deck Safety Month, and recently deck collapse has become a real issue. Poorly built and older decks have become the cause for many personal injuries and even death.


The North American Decking and Railing Association (NADRA) estimates that 40-50% of the 40 million residential decks in the U.S. are not up to current code or are in danger of collapse.

According to the Consumer Product Safety Commission (CPSC), an average of 6,000 people per year are injured because of the structural failure or collapse of a deck, porch, railing, or staircase.


The most tragic deck collapse occurred in June of 2003 when a porch gave way in Chicago, killing 13 people and injuring 57. This incident created a concern for deck and porch safety across the country.


To avoid deck collapse or injury, here’s a deck safety checklist you can do for your own deck:


1) Inspect Ledger Board and Flashing

According to International Association of Certified Home Inspectors (InterNACHI), about 90% of deck collapses occur as a result of the separation of the house and the deck ledger board, allowing the deck to detach from the house.


Up until 2003 it was acceptable to attach a deck directly to a house using only nails. However, after the tragic deck collapse in Chicago, a mandatory piece of material called the ledger board must be bolted to the house.


This load-bearing ledger board secures the deck to your house. Make sure it’s attached with ½-inch stainless or galvanized steel lag screws and through bolts, rather than nails, which can pop out. Check for a widened gap between the house and the ledger board, which may signal that the bolts need to be tightened or replaced.


Metal flashing protects the ledger board from moisture which can cause wood rot and structural damage. Look to see if it has pulled away from the house, and make sure the caulking that seals overlapping pieces is intact. Replace if necessary.


2) Check for Loose Railing or Stairs

Deck railing is an essential safety feature for the deck. Firmly grasp and wriggle the deck railing to make sure they’re secure. Railings are supposed to withstand about 200 pounds of lateral force. If it sways when you push on it, have an inspector check it out immediately.


If your railing is secure, inspect it closely for minor damage and reinforce any loose parts and replace damaged pieces. Also double-check whether the railing meets local codes, which generally call for a railing at least 36 inches high with less than a 4 inch gap between balusters.


Just like any stairway, deck stairs require a railing. Any swaying or wobbling is cause for concern. Additionally, the stair steps should be solid and not sag or shift. Secure loose boards and replace any that are damaged.


3) Check for Rusted Fasteners and Connectors

Take a look under your deck to see if your fasteners and connectors are sound. Items that hold your deck together (including nails, bolts, screws, and joist hangers) should be made of galvanized steel, but this material still needs a close inspection; even galvanized steel can rust.


Check the joist hangers, which hold the joists in place. Every hole should have a joist hanger nail securing the hanger to the deck frame. If you need to add nails, use joist hanger nails which must be long enough to go through the floor joist and into the frame.


Secure any loose fasteners. If you notice nails that have worked out, replace them with deck screws. Replace any damaged hardware. Check fasteners and hardware for rust and corrosion, which can weaken the wood. Replace them as needed.


4) Inspect Deck Posts and Footings

Check the soundness of the deck post and post footings. Deck posts should be attached to concrete post footings with post anchors. Check the post footings for any sinking or cracks in the concrete. Make sure the connection between the deck post and post anchors is not loose or corroded.


Look for loose connections between posts and the deck’s beams. Tighten and replace ½-inch through bolts as needed. Posts should be 6 inches square or larger, and no taller than 14 feet without bracing.


5) Check for Rotted Wood or Insect Damage

Inspect several locations for rotten wood. Give particular attention to parts of the deck that are regularly damp and areas around fasteners. If the wood breaks easily without splinters, it does not hold a deck nail or screw, or if you can easily push a screwdriver 1/4 to 1/2 inch into the wood, there may be rot.


Pay attention to soft spots as you walk across the deck. These may also indicate decay or insect damage. Treated wood and composite materials used in decks are usually resistant to rot and insects, but the areas of the house that connect to the deck may not be.


If you need help inspecting, repairing, or replacing your deck, we’d be happy to help you out! Give us a call today at 541-926-3117 or email us at info@tntbuildersinc.com for your free estimate.
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