Is Your Deck Safe? Top Five Construction Mistakes
Do you have a deck attached to your home? We love the camaraderie of being outside on our decks with family and friends and probably don't think much about safety.
When was the last time you inspected your deck or had someone else inspect it? Don't remember? 224,000 people were injured in accidents involving decks or porches from 2003 to 2007 when the Consumer Product Safety Commission conducted a formal study.
15% of those injuries resulted from structural failure or collapse of the deck.
How could this happen? As a home inspector, I can tell you from what I see on inspections that I'm surprised that there aren't more failures.
Of all the homes I have inspected in the last 3 years, about 75% of the decks were not constructed correctly.
With a little age and wood rot, structural failure is completely possible.
Here are the top five mistakes made in deck construction, and what you can do to prevent unexpected failure.
When was the last time you inspected your deck or had someone else inspect it? Don't remember? 224,000 people were injured in accidents involving decks or porches from 2003 to 2007 when the Consumer Product Safety Commission conducted a formal study.
15% of those injuries resulted from structural failure or collapse of the deck.
How could this happen? As a home inspector, I can tell you from what I see on inspections that I'm surprised that there aren't more failures.
Of all the homes I have inspected in the last 3 years, about 75% of the decks were not constructed correctly.
With a little age and wood rot, structural failure is completely possible.
Here are the top five mistakes made in deck construction, and what you can do to prevent unexpected failure.
- Wrong or missing hardware.
Look for nails in every bracket hole, and a bracket (called a "bucket") under every joist, or wood member, attaching it to the main beam under your decks. - Temporary piers under deck posts.
Do you see a concrete block (called a "pre-cast foundation block") sitting on top of the soil with the post sitting in it?A result of lazy building, these blocks under your deck posts can, and do, move.
I've seen some posts out of plumb by as much as 20 degrees.
Posts should be attached to a concrete pier that goes into the soil below the frost line.
Securing the pier below the frost line prevents movement, and setting the wood post on a pier above ground helps prevent rot. - Incorrectly attached deck ledgers.
The deck ledger is the board that everything else on the deck is fastened to that secures the whole assembly to the side of your house.
Imagine this particular board detaching from the house.
Are you thinking what I am thinking? You are correct - the entire deck will detach from the home and fall outwards.
To inspect, go under your deck and look for large bolts (not nails) at regular intervals.
Ledgers should not be fastened to brick, stucco, or foam without specialty hardware, as they can pull out. - Beam bolted to the sides of posts.
Always place deck posts directly below beams and attach them securely.
Beams bolted to the sides of posts are not as strong.
While the bolt may not fail, the wood itself can shred or shear. - Incorrectly attaching deck guardrail posts.
A guardrail by code is supposed to be able to withstand a load of 200 pounds in any direction along its top.
Would you be afraid to try this test on your deck rails? If you find your rails the least bit wobbly, get someone to install extra hardware correctly to make it safe.
