How to Build a Deck
Submit Building Plans to Plan Review
Question: "Can I just build from this Preliminary Plan I drew up? I mean, do I really need anything else? I like flying by the seat of my pants."
Answer: Didn't I see you barnstorming my nephew's birthday party last Saturday? Was that you? You should be ashamed. Once you have determined the basic design of your deck, you will need to work with an expert who knows code requirements, has access to span charts and can calculate loading requirements in order to generate a detailed and complete set of code compliant Building Plans. Most folks use an architect, engineer or professional deck design and build firm (like us). Once you have these working drawings, submit them to your local Plan Review for their study and comments. Even if your locality does not require a building permit for a deck, this is still a smart move. Your taxes pay their salaries. Use your Building Department's Plan Review as a double check for your set of Building Plans. And listen to what they tell you. Most of them are quite good at what they do.
Selecting and Ordering Materials
Question: "I am not a carpenter. How will I get a materials list drawn up so I can order all this stuff?"
Answer: You can pay a carpenter or deck builder to work up a materials list for you. It'll take 'em maybe a couple of hours depending upon the size and charge you... oh, I don't know... maybe $50 or $100. Or you can work it up yourself (get ready to make some return trips to the local materials supplier). But here's a little known secret that will save you some time and trouble: If you have good, clear Building Plans drawn up (which is very important to have if you are going to build this yourself), just take a copy down to any reputable materials supplier and ask him for an itemized quote. He will happily provide you with a materials list complete with prices... free. Why? He wants to sell you the materials! Now you've got a materials list and you can comparative shop. Some suppliers won't do it. Good ones will.
Preparing the Ground
Question: "I've heard conflicting reports. Some say I should remove the sod where my deck will go, others say to kill the grass with a vegetation killer, others say do nothing. Still others tell me to put down black polyethylene to prevent weeds and grass from growing through the deck. I'm really confused. What's right?"
Answer: Well, think about it. If you remove the sod, what will prevent the water that comes from the deck from eroding the ground under your deck? Sod is good. Grass is good. If there is not enough sunlight to sustain the grass, it will die. But that's ok. The sod that remains will prevent erosion. If the deck will be fairly low to the ground (4' or so), you may want to skirt it with something like lattice for aesthetic reasons. But if it's higher, sometimes lattice skirting becomes over bearing. In that case, there should be enough light to sustain some kind of vegetation. Try it. If not, you can always concrete it or put stone under the deck.
Laying It Out
Question: "What must I do to lay this deck out?"
Answer: You must establish the exact location of each footing. This is extremely important, so take time and care here. Your plans should have the distance from the house and the lateral distance for each footing so you can determine the exact location for each one. Carefully measure and mark each one with a can of spray paint. In most cases, the ground slopes away from your house, so you cannot simply measure along the ground from the house. You will need the exact location of each footing which can be determined by use of a measuring tape held horizontally (you may need a line level here) and a plumb bob held on the end of a string. Remember that most of the main support footings will lie on a straight line parallel to the house wall. Before you dig, use a string to determine that the main support footings are in fact all on a straight line and equi-distant from the house wall. Another excellent double check to insure the line of main footings is properly spaced from your house is to lay out a rectangle with string on the ground in which the house wall forms one side, the line of main footings form the opposite side, and the two exterior footings form the two exterior corners. Two diagonals must be equi-distant for this to be a perfect rectangle. If the diagonals are not equal in length, shift the line of footings right or left (keeping it parallel to the house wall) until the diagonals are exactly equal. Then you know you have a perfect rectangle. If your ground slopes, you will need stakes and a line level to make this work.
Attaching the Ledger
Question: "What is the significance of a ledger board?"
Answer: If your deck will not be free standing (attached to the house, but not supported by the house), you will need to attach the deck to the house wall in such a way that the house supports the deck. The board that is attached to the house is called a ledger or band. It must be level and attached with 1/2" lag or carriage bolts staggered high and low and spaced according to code. If you are attaching the ledger to a house band board (board that faces off the ends of the house floor joists and rests on the foundation wall), the house band board must be a minimum of 1.25" thick. Anything thinner cannot support your deck and must have solid 2x blocking inserted behind the house band, resting on the foundation wall, and toe nailed to each house floor joist. The ledger is then attached with 1/2" lags or carriage bolts through the thin plywood house band into these 2x blocks which will support the deck. If blocking behind the house band is not possible, you may need to drop the elevation of the deck so that the ledger may be attached to the house concrete foundation wall (use concrete expansion bolts approved by your local Building Official) or a beam will be needed to support the deck at the house wall. In either event, be sure to run 10" or so of aluminum flashing on top of the ledger and up behind the house siding in order to prevent water from gaining entrance to your house. Also be sure to run silicone caulking into every hole you make in your house wall as you attach the ledger so you seal your house against water.
Question: "Anything I should know about footings?"
Answer: That's a joke, right? If you mess up your footings, you might as well not finish your deck because it won't be worth much when you do! First of all dig your footings to the depth recommended by your local Plan Review. They know the correct footing depth for your geographic area. Don't guess. And be sure your footing depth is deep enough that each footing will rest on solid, undisturbed (virgin) soil. This is critical or your deck will sink. Do not build on fill dirt. On the other hand, if your house has been built on fill dirt, or if you have not reached solid, hard dirt in 4' or so... do not continue digging without taking proper measures to shore up the holes and prevent a dangerous cave in. It's happened where folks have lost their lives in digging too deep a footing and it caved in on them and they suffocated. One man I heard of was lying on his belly on the surface while using a post hole digger. (You'd think that was safe, wouldn't you?) But he accidentally fell head first into the hole and could not work himself out for 30 long minutes. Had there been water in the hole, he would have drowned. His partner had left to run an errand and no one could hear his cries for help. He backed himself out agonizing inch by agonizing inch with his toes and his finger tips. Please don't do something dumb. It's a deck and it's not worth dying for. An alternative to digging past 4' feet is to call a local soil engineer and have them test each footing. They might charge you $30 or so for each footing. But they will be able to tell you exactly how large to make each footing in order to sustain the weight of the deck given your soil analysis... and your local Building Official will accept their report. Once your holes are dug and you've obtained a good footing inspection from your local Building Inspector, mix concrete in each hole (follow the directions on the bag) so that the concrete is a minimum of 8" thick and very level. You do not want it uneven.
Question: "What kind of posts do I use and how do I attach them to the concrete?"
Answer: You can use 4x4s if your deck is low (2' or less) and if your local code permits it... but I would still recommend using 6x6s for the main support posts. They look better and they are much easier to attach the beams to that will rest on them. After the concrete has set, stand each 6x6 on top of the concrete footing. Repeat the procedure under Laying It Out above for insuring a perfect rectangle. Use a level to plumb each post in both directions and use temporary braces to hold each post in place. Insure the 6x6s are on a line if they are to support the same beam. Once each of the 6x6 posts are in place and supported, run a string and a line level from the top of the ledger board to the post. Mark each post. This represents the top of the floor joists. But the joists rest on a beam which rests on the 6x6. So then measure down the width of your floor joists plus the width of your beam and scribe a line on each post for cutting a pocket out to hold the beam. You should leave enough wood on the 6x6 so that you can use 1/2" carriage bolts to bolt through the 6x6 and through the beam thereby holding the beam on top of the 6x6. The length of your post from the concrete to the horizontal cut should be such that the beam resting on the horizontal cut with joists resting on the beam brings the top of the joists level with the top of the ledger... or perhaps a 1/2" lower than the ledger to allow for water to roll away from the house... though normally footings will sink 1/2" or so anyway. Some localities want you to attach the posts to the concrete which you can easily do with "L" brackets. But don't do it yet. See Footing to Post to Beam to Joist to Ledger Detail drawing below.
Question: "Let me get this straight. I've got concrete in my holes, 6x6 posts standing tall on top of the concrete all marked and ready to cut, and the ledger attached to the house. What am I supposed to do now?"
Answer: Cut the 6x6s with a Saw Zaw. Make a horizontal cut (no further than needed for the beam to sit totally on the 6x6) and a vertical cut so that the 6x6 can be attached to the beam with carriage bolts. Nail your beam together according to code and insert it on and into the pockets cut into the 6x6s. Drill holes through the 6x6 and beam and attach the beam to the 6x6 with two (2) 1/2" x 7" carriage bolts with nuts and washers. Insure the beam is level and the 6x6 posts are plumb. Insure the beam is parallel to the house and the proper distance from the house. Once you know the beam is right, use more temporary braces and make it very secure so a man could sit on it safely. Important tip: If you cannot make a beam of continuous 2xs, then insure the break in the beam is over an interior 6x6 (NOT ON AN EXTERIOR 6x6). Always insure a break in the beam occurs directly over a post. And attach the broken beam by running four (4) carriage bolts through the beam and 6x6 post. Attach with nuts and washers.
Question: "OK. I'm with you. I'll bet you want me to lay floor joists next...?"
Answer: Say, you're a quick learner. And the way you do that is by starting from the left side of the ledger and marking off where each of the joists will go, either 12" OC or 16" OC or 24" OC depending upon your Building Plans and code requirements. Then do the same thing on the top of the beam. Set the joists in place (crown up). Most carpenters will toe nail all the joists to the ledger first, then go back and install the joist hangers (putting a nail in every single hole and being sure to use joist hanger nails only). If your deck is so far out from the house that two sets of floor joists are required, be sure to overlap the joists by about a foot on the beam, nailing them together at the overlap. Install blocking between the floor joists around the perimeter to stiffen the outside joist for railing attachment. Install any additional blocking necessary to fulfill local code. Nail the rim joist to the ends of the floor joists.
Question: "If I don't miss my guess, decking is next. Anything important I should know here?"
Answer: Everybody's a comedian. Of course this is important. Lay the deck boards so that the best side is up. Ignore whether the cup is up or down (end grain looks like a cup). This is one of those deck building myths that well meaning carpenters have perpetrated for years. See my "Hints & Tips: A Guide to Common Deck Building Problems" for the reasons. I don't recommend you install decking parallel to the house for two reasons: 1) Decking parallel to the house and perpendicular to the joists does nothing to keep the deck in rack (square) so it will shake on you unless it's cross braced below. 2) A deck board parallel to the house and up against the house wall tends to hold water against the house. Never a good idea. Running the decking on a diagonal keeps the deck in rack, runs water away from the house, and looks better to boot. Just insure that you stick to a 45 degree angle, no more. Running 5/4x6 pressure treated pine decking on a 45 degree diagonal between floor joists 16" OC means you will be spanning over 20" with the deck boards. That's within code, but it's close. Don't go over a 45 degree, and feel free to cheat it back to a 40 degree. You'll never see it and the decking will have very little spring in it. Tip: Don't want to splice the decking? Running the decking one direction may result in splices, but the opposite direction may not. If that doesn't work, break it up with a deck "break" board right down the middle (needs extra joist and blocking below), and run a herringbone pattern. That way you can avoid splicing deck boards. If you do need to splice, for heaven's sake, end the deck board in the middle of a joist so you can have something to nail to. Tip: If you will cut the ends of the spliced deck boards on opposite angles (under cutting the one and over cutting the other), they will overlap and when they shrink, the resulting gap will not be as noticeable. It's tricky but cool. And, and if you are splicing, be sure to stagger the joints so that the splices don't line up. Totally ugly.
Question: "I've heard from my buddy at work that I should gap the deck boards. That true?"
Answer: False. You're buddy's living about 30 years in the past. Never gap 5/4x6 or 2x6 pressure treated decking unless it's kiln dried. If you do, they will shrink as they dry and you've got 1/2" to 3/4" gaps. A real eye sore and high heel catcher... and it won't be funny when Mom walks right out of her shoes. If the boards are kiln dried, you should gap them 1/8" because they won't dry and shrink anymore and you want water to run out. Otherwise, butt those boards as tightly together as you can. Jam 'em!
Question: "Should I use 2 or 3 nails at each joist?"
Answer: Two nails is fine, one about 3/4" from each edge and on an angle (helps to hold better). Use hot dipped galvanized (resists rusting) or stainless steel spiral or ridge shank nails (for superior holding). And if you will run a thin (I said "thin") bead of exterior pressure treated wood adhesive down the top of each joist before fastening the deck board, it will prevent nail pops. See "Hints & Tips..." for reasons. Deck screws work fine also. I like the ceramic coated screws instead of galvanized. Heads don't strip out and they won't rust ever. Just know what you're buying. You might want to pre-drill the ends of the decking before nailing so you don't split the ends. Some folks use a galvanized siding nail just for the ends and use three at the end. The siding nails are a tad thinner than regular deck nails and so don't split the ends as easily.
Question: "What, do I measure and cut each board... suppose it's too short?"
Answer: Cut it again! Just kidding. Actually, the best way is to lay the decking with one end precut and fitted under a piece of siding if possible, while the other end runs wild over the end of the rim joist (band) or last joist. Then just strike a chalk line and saw the ends off at one time. Neat, huh.
Question: "Is it done yet? Tell me it's time for an ice tea in the shade with a pretty girl feeding me grapes..."
Answer: No such luck, my friend. Not yet. You've got to get up and build your railings! First you will want to secure each post (normally 4x4s) at each corner of the deck (attaching to joists perpendicular or horizontal to the house wall if possible). Typically you will use two 1/2" carriage bolts with nuts and washers per post. Stagger the bolts slightly off center of the post. Then equally space the interior posts such that you do not exceed your local code requirements (typically 5' max between railing posts). Insure posts are plumb in both directions. Run the top and bottom sub-railings (normally 2x4s on edge) around the top and bottom of the posts. We like to run them continuously where possible along the inside face of each 4x4 which adds strength to the railing. Be sure to put a couple of 2x4 spacer blocks under each of the bottom 2x4s pieces before you nail them. Connect the tops of the posts with a 2x6 cap laid flat, continuous where possible. Don't forget, when cutting for a 45 degree angle, you cut a 22.5 degree on each side. But you may find it quicker and easier and more accurate to overlap the 2x6 cap pieces and simply scribe from corner to corner each board. Then cut. Then screw your 2x2 vertical pickets to the outside of each 2x4. Bring the top of each picket flush under the 2x6 cap, and cut the bottom off on an angle. Tip: Want proper spacing of the pickets and minimize waste? Layout each railing section for pickets as follows: Mark the center of the top 2x4. Measure slightly less than 2" to the right and mark and slightly less than 2" to the left and mark. Install pickets on those marks such that the distance between them is slightly less than 4" (current code requirements in most places as of this writing). Scribe and cut a block to this gap. Plumb only one picket and screw it to the bottom. Use the block to gap the other picket and attach it. From this point on just use the block to gap each picket. If you've spaced your 4x4s equally, the resulting gaps between 4x4 and 2x2 on each side should be equal. And by starting in the exact center with two (not one) pickets, you will save one or two pickets on each section.
Question: "Can you help me with questions about installing cedar shake shingle?"
Answer: Help you? Help you?!? I know "the man" who can help you... none other than Mr. Shakey himself. Just click on his picture and email him any question you want about installing cedar shake shingles!
Question: "OK. I'm ready to start. I feel like I've aged just reading this thing. What kind of tools do I need to get going?"
Answer: My friend... you need the following: String (mason's line), line level, wheel barrow, pencil, level, carpenter's framing square, tri-square, hammer, skill saw with carbide blade, Saw Zaw, heavy duty drill with half inch wood bits 10" long, hammer drill (if attaching ledger to existing poured concrete wall), adjustable wrench, chalk line, measuring tape (steel), plumb bob with string, stain and brushes. Your friendly local materials supplier should provide you with the list of building materials. Good luck! But remember something: No amount of coaching and reading and studying of how-to deck building manuals (even if written by the Bob Villa of decks) can prepare you for every contingency and every possible problem. If you develop a problem or have a question or don't really know what to do... get help! Ask somebody who knows! Don't be hard headed and muddle through on your own. There are plenty of folks around who can offer good, sound advice. Find one and ask him.
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