Deck construction


Deck failures are constantly in the news. Deck construction is serious business and should not be take lightly. These are structures that hold peoples lives in their hands, yet some people think a case of beer, a trip to the lumber yard and two days with their friends is all that is needed to build a deck. One common quote is “I have been building decks like this for 20 years”. Well guess what codes change. The building practices of your father or grandfathers generation have changed. Change is good when it comes to safety, especially for your friends and loved ones.

Deck construction issues stem from ledger failures to corrosion of the fasteners, to lack of footings and the age of/or deterioration of the materials. You name it there are many reasons why decks fail, the reason should not be because it was built using the techniques of 30 years ago. You ask “How do I know what to look for when building a deck, what questions do I ask?” The one standard question you should always ask everyone who works on your home is, are you licensed and insured, do they have references. In the age of social media you can look up online reviews. If you can’t find any online reviews you are likely dealing with a newer contractor, so ask for references. No online reviews isn’t a bad thing, you just need to do a little more work. Of course when reading online reviews make sure they are written by actual paying customers not their buddies or family. Next ask if they pull permits, ask what codes they follow when building the structure. One of the biggest signs someone is knowledgeable with deck construction is if they use the American Wood Councils “Prescriptive Residential Wood Deck Construction Guide”. This is the best guide available to anyone building a deck. It is free and it is available online. http://www.awc.org/publications/dca/dca6/dca6-09.pdf

One of the oldest and most common techniques for supporting a deck is attaching the beam to the sides of the support posts. Sometimes this is done with nails only, other times they upgrade to one bolt. The point loads should rest on the support posts. The beams should sit on top of the 6×6 support posts. The other major failure point is the ledger attachment, from insufficient bolting to rotting wood behind the ledger this is the most critical support point of the deck. If the ledger is not attached properly it could lead to a major failure. Attaching a ledger properly involves flashing, bolt spacing, the proper bolts, bolting in to structure which can support the loads (not brick veneer) and bracing to prevent lateral movement. There are so many factors which go in to properly constructing a deck it should not be taken lightly. Call a professional. If you still want to tackle it yourself, read the guidelines referenced above and then call a professional. If you still want to build it yourself pull the permit and have the city inspect it to double check on your work. Some jurisdictions require the deck to meet the guidelines, others do not. But if you build it using this guideline when building a simple one story deck you should be on the right track.

If you have an old deck, are concerned about the decks construction and want to know more about it’s ability to provide a safe place to entertain or you want advice on how to improve it’s safety, call a home inspector. Most home inspectors will come out and inspect the structure for you. Some will give you a report, some will offer advice it just depends on what you want to pay for. Seeking a professionals advice over the family member who “thinks” they know how to repair it, is the better approach. Call an ASHI certified home inspector or a licensed contractor.