April 22nd, 2015

Is Your Deck a Disaster?

Home Owners Network

 What grade would your deck receive?  Would it receive an A, meaning it should give you years of trouble-free service, or would it receive a D, meaning it’s a disaster waiting to happen?  Injuries from deck disasters number in the thousands every year.  Here are some tips to help you grade your deck.  The information in this article represents nationally recognized best practices.  Requirements in your area may be different.

 Deck Attachment to the House

 Most catastrophic deck collapses occur because the deck pulls away from the house.  The two most common reasons that decks pull away are wood rot where the deck attaches to the house and improperly installed fasteners used to attach the deck to the house.  These two reasons often act together.

 Wood rot occurs when water leaks behind the board that attaches the deck to the house, called the deck ledger.  Water leaks behind the deck ledger because there is no flashing at the deck ledger or because the flashing is improperly installed. Few decks will be ideally flashed and you won’t be able to see all of the flashing, but if you don’t see any flashing, you have a problem that needs repair.

 The deck ledger should be attached to the house using at least ½ inch diameter hot-dipped galvanized steel machine bolts or lag screws.  The ledger should not be attached through any exterior wall covering material, especially not through brick veneer.  The bolts or screws should be attached to at least a 2 inch thick piece of lumber or at least a 1 inch thick engineered rim board inside the house. Deck ledgers not attached as shown in this illustration may be a problem that needs repair.

 shutterstock_109385036Deck Stairs

 Stairways are common accident areas and deck stairs especially so.  Because deck stairs are exposed to the elements, they are more prone than interior stairs to deterioration and movement that can cause accidents and even cause stairway collapse.

 One common problem with deck stairs is inadequate attachment of the stairs to the deck.  All of the stair support lumber should bear on the deck where the support lumber attaches to the deck.  The stair support lumber should be attached to the deck using joist hangers or some other type of bracket.  Nails are most often used to attach the stairs to the deck, but nails are subject to withdrawing from the deck.  Look at where the stair support lumber attaches to the deck.  If the stairs are pulling away from the deck, you may have a problem that needs repair.   

 Handrails and Guardrails

 Handrails and guardrails are important deck safety components.  Both are there to keep people safe from fall injuries. Handrails and guardrails should be securely fastened to the deck using 4×4 posts spaced not more than every 6 feet and secured using attachment brackets.  Posts that are not full 4x4s (notched posts) and posts secured using only nails are a problem that needs repair. Handrails should provide a graspable surface, especially for children, small adults, and people with reduced mobility.  For example, the diagonal measurement of a rectangular handrail should be not more than 2¼ inches.  The diagonal measurement of the 2×4 handrail installed with most deck stairs is 2⅞ inches and does not provide a safe graspable surface.  A 2×4 handrail are a problem that needs repair.

 The Bottom Line

 There are many things to look for when grading a deck.  This is a short list of things you can look for.  Decks that are older than 15 years may be approaching the end of their service lives.  You should consider having a home inspector grade your older deck.  Older decks have a higher risk of being a disaster waiting to happen.

 We’re here to help at Home Owners Network.  Use our ‘Ask the Experts’ service if you need help.  Please include as many details as possible about your situation so we can provide you with our best advice.

 If you need a qualified technician to help you, try our ‘Find a Contractor’ referral service.  Log on to your Home Owners Network account to access the ‘Find a Contractor’ page.

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