Submit Building Plans To Plan Review
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 to generate a detailed and complete set of code compliant Building Plans. Most folks use an architect, engineer or professional deck designer and build firm.
Once you have these working drawings, give them to your local Plan Review for their study and comments. Even if your locality does not need 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 good at what they do.
2. Selecting and Ordering Materials
You can pay a carpenter or a deck builder to work up a materials list for you. It’ll take ’em maybe a couple of hours depending on the size and charge you. 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 give you 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.
3. Laying It All Out
You must establish the exact location of each footing. This is extremely important, so take time and care here. There is 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 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 equidistant from the house wall. Another excellent double-check to ensure 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 are equidistant for this is 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.
4. Attaching The Ledger
If your deck is not 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. Attached is a board to the house called a ledger or band. It is 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 ( the board that faces off the ends of the house floor joists and rests on the foundation wall), the house band board is 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 toenailed 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 the deck elevation, dropped so that the ledger is attached to the house concrete foundation wall (use concrete expansion bolts approved by your local Building Official) or beam is 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 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.
If you mess up your footings, you might as well not finish your deck because it’s not 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 fingertips. 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 £25 or so for each footing.
But they will be able to tell you exactly how large to make each footing 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.
6. Decking Posts
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 6×6 on top of the concrete footing. Repeat the procedure under Laying It Out above for ensuring a perfect rectangle. Use a level to plumb each post in both directions and use temporary braces to hold each post in place. Ensure the 6x6s are on a line if they are to support the same beam.
Once each of the 6×6 posts is 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 6×6. You should leave enough wood on the 6×6 so that you can use 1/2″ carriage bolts to bolt through the 6×6 and through the beam thereby holding the beam on top of the 6×6. The length of your post from the concrete to the horizontal cut 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.
Cut the 6x6s with a Saw Zaw. Make a horizontal cut (no further than needed for the beam to sit totally on the 6×6) and a vertical cut so that the 6×6 is 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 6×6 and beam and attach the beam to the 6×6 with two (2) 1/2″ x 7″ carriage bolts with nuts and washers. Ensure the beam is level and the 6×6 posts are plumb. Ensure 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 ensure the break in the beam is over an interior 6×6 (NOT ON AN EXTERIOR 6×6). Always ensure 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 6×6 post. Attach with nuts and washers.
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 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 toenail 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 you need two sets of floor joists, 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 more blocking necessary to fulfill local code. Nail the rim joist to the ends of the floor joists.
9. Deck Boards
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. I don’t recommend you install decking parallel to the house for two reasons:
- Decking parallel to the house and perpendicular to the joists does nothing to keep the deck in the rack (square) so it will shake on you unless it’s cross braced below.
- A deck board parallels to the house and up against the house wall tends to hold water against the house. Running the decking on a diagonal keeps the deck in the rack, runs water away from the house, and looks better to boot. Just ensure that you stick to a 45-degree angle, no more. Running 5/4×6 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 the 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 (undercutting the one and over cutting the other), they will overlap and when they shrink, the resulting gap is not 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.
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). Ensure 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 4×4 which adds strength to the railing. Be sure to put a couple of 2×4 spacer blocks under each of the bottom 2x4s pieces before you nail them.
Connect the tops of the posts with a 2×6 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 2×6 cap pieces and simply scribe from corner to corner each board. Then cut. Then screw your 2×2 vertical pickets to the outside of each 2×4. Bring the top of each picket flush under the 2×6 cap, and cut the bottom off at 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 2×4. 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 4×4 and 2×2 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.
You will need the following: String (mason’s line), line level, wheelbarrow, 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 give you the list of building materials. Good luck! But remember something: No amount of coaching and reading and studying of how-to deck building manuals can prepare you for every contingency and every possible problem. If you develop a problem or don’t really know how to build a decking get in touch with someone who does.