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Deck Tips Before You Start
A staged model unit missing one critical part! Decks are one of the more common do-it-yourself projects undertaken and even when “contractors” are hired I’ve been surprised at the misses. As you begin to plan and prepare for your deck renovations and replacements I want to offer you some important tips. These come from the most common mistakes and shortcuts I have seen in the course of my inspections. There are codes and requirements that provide the essentials of a safe and proper deck, but planning and reading may not be a DIYers top priority when the lumber is sitting in the yard and a barbecue is begging for a new platform.
TIP: Get ready for sticker shock! You plan and budget and get the current pricing but by project-end you will discover that your deck is 20-percent more expensive than you estimated! Time, labor and cost will inevitably cost more so budget for it.
Railings and hand rails
Metal posts and cable and clear pane systems are growing in popularity, but most people do not buy these high cost, pre-fabricated systems nor want to wait for their construction and delivery. Therefore, 4×4 posts with top rails and balusters are the go-to. Don’t cut or notch the 4×4 at any point. It is a 4×4 only as long as it is 4×4 for its entire height. This is true for every piece of lumber BTW!
Notch for horizontal rail has caused split in post and compromised the 4×4 post strength 
Notch at base compromised 4×4 post strength 
Improper screws used to secure railing and the post is cut short Two 1/2″ bolts are needed to adequately secure the post to the rim joist. Ideally these will be bolted inside the rim joist. Be sure this rim joist is doubled up and capable of stabilizing the forces applied to the railing. A railing is suppose to sustain the fall of a 200-pound adult. So, as I jokingly say, if your uncle is on his third beer and trips and falls, he ends up with a shiner on his forehead rather than worse.
Ledger House Connection
Ledger with no visible anchors – 1/2″ bolting needed The board that attaches the deck to the house, called the ledger, must be securely bolted to the structural components of the house. Usually 1/2″ lag bolts are run into the header and studs hidden behind the siding materials. We worry about falling down more than sideways but vertical and horizontal strength are equally important. A majority of deck collapses are actually with the deck pulling away from the house. The design must accommodate the stress of all the friends and family peering over to admire the workmanship below. Additional bolt and cable bracing is now required for decks to ensure the structure will never move (horizontally) away from the house.
Once the ledger is adequately secured to the house remember that this feature MUST withstand all the weather and moisture challenges. As the ledger goes so goes the deck! Installation of flashing to channel water away and prevent moisture from entering behind the ledger is often overlooked. Decks have a gradual negative slope to guide water away from this connection. But the water running down the siding above the deck and collecting near the house-deck connection can enter behind the ledger and create significant problems. Flash it! The ledger should remain bone-dry year round! A wet ledger is a bad omen.
TIP: Over build it! Cheaper is a dangerous guiding principle with deck building. You might get away with cost-savings when it comes to sheds or fences, but this is a legitimate feature that can be a matter of life and injury and more. As you over-build-it consider how your deck would fare if you parked your car on it or, more practically, decided to install a hot tub or had 3 feet of ice and snow piled upon it. An over-built deck to this inspector is like a 600+ horsepower engine to a car enthusiast!
Protect or Seal It
Cross grain is where the rot starts. The cedar grain of decking boards withstands moisture wonderfully but it is the cross grain end cuts or penetrations where moisture will enter and deteriorate the boards first. Protect cross grain with top rails, flush installation of fasteners (rather than deep countersinking), and sealing any areas like splits or knots where water might collect. Overall protection can be provided with an all-weather sealant and stain that will likely need to be re-applied every 2-3 years. Be sure to liberally apply it to the cross-grain areas!
Screw it don’t nail it
4×4 angle brace inadequately secured with two small screws Nails back out over time which is a major concern with an outdoor structural system. Screws prove themself in the test of time. It is important to use the proper size (width and length) screw for the lumber dimension and function. Screws should be approved for outdoor use and be galvanized steel and not prone to rust. The goal is for the screw to fully enter through both boards without protruding through the backer board. In some cases bolts, washers and nuts can be used as the silver bullet to ensure two boards will never (EVER) separate. Railing posts are a great place for these.
TIP: Pre-drilling holes will prevent cracks that form when screws are installed. Cedar is a soft wood that can handle penetrations but over-tightening or larger screws can split the wood compromising its strength. The proper-sized screws (width and length) are essential. The picture here shows a DIYer who misused his deck flooring screws to secure a 4×4 angle brace. Cheaper and convenient are not welcome partners in building design!
Kid-Proof spaces and design
Young children will find the fatal flaws in every jungle-gym deck project. The railing should have no space larger than 4″. This includes between the spindles and the clearance under the railing. Additionally, stairs are not to have open tread in which a 4″ sphere (ball) could slip through. What do we learn about all this 4″ business? A young child’s head seem to be about 4″ in diameter.
Gap in step riser more than 4″ 
Gap between balusters nearly 6″ rather than 4″
Earth to Wood Contact
Minimize the places where wood is in direct contact with the ground. The ground includes soil, gravel, concrete slab and any other landscape materials where high moisture or wood-destroying pasts might be. If a material is in direct contact, like trim boards stringer for stairs (pictured below), it must be a treated material or installed with a moisture proof barrier (like tar paper or a roofing shingle).
Sometimes deck posts get wood chips, dirt, grass or even water collecting at the base. For a long lasting deck wood, prevent ground to wood contact. Concrete piers and metal posts can provide needed spacing and moisture protection.
Your Barbecue’s New Home!
Get on with the reading and proper planning now while the weather is crummy. There is much more that goes into the actual deck build but hopefully you can avoid some of the problems and costly repairs of these common deck-building misses. If you have questions or even a successful (or less than successful) story of a deck building project I would love to hear it! As always, you are the favorite part of my job and I enjoy being a continued resource as you make your house a home!
