Last time we talked about the basics of design for your deck, and the materials that you might use. The most common choice of materials is pressure-treated (P/T) lumber as we said but cedar or composite and vinyl are all being used. As a rule, pressure-treated lumber is the best and cheapest choice for the structure of your deck but what you use for the visible parts of the deck will depend on your budget and the look you are after.
The instructions below are generic and you must be sure you comply with all local building codes before determining your final design or doing any work.
Determining the position of the posts and beams:
You should determine the spacing between your beams first then you will be able to determine the position of the support posts and the joist size appropriate to that spacing. Depending on the size of the deck I prefer the beams to be no more than 8’ apart and then I use 2×6 joists, this meets most code requirements but sometimes it makes more sense to space the beam up to 12’ apart and then use the size joist size appropriate to that dimension. Often a deck will only need one beam along the outer edge of the deck with the other end of the joist supported be a ledger bolted to the house. These beams can be made many different ways, and the spans will vary by how you build it. I tend to use 2 – 2×6, one on either side of your support posts but doing this means you need a support post approx. every 4’.
Determining Joist Size:
2x6s through 2x10s are the most common sizes used for joists. Again I prefer using 2×6 joist set on 16” centers though with full 2” decking you can set them on 24” centers. If your span is greater then 8’ you will need to use a bigger joist and maybe even set them on 12” centers. Your local building center should be able to help you with what meets code in your area. Again pressure-treated lumber is generally less expensive and is used for the joist even when the decking and railing maybe of a different material.
Building your deck:
1. 
Position the ledger along the wall the thickness of the deck boards below the height you want your deck. The height you want your deck should be at least 1″ below the bottom of the door out onto it. Fasten the ledger to the wall with 1/2″ lag bolts or sleeve anchors in concrete. The ledger should be level, and the lags or bolts should be at least 3″ long and should be spaced no more than 3’ apart.
2. 
To establish the outside perimeter of the deck, measure out from each end of the ledger about 18″ beyond the outside edge of the deck. Set up batter-boards as shown or stakes then run taut strings from the ends of the ledger to the batter-boards or stakes to establish the sides of the deck. Then run a third string between the batter-boards to establish the outside edge of the deck. Check your strings for square making sure you maintain an equal distance between the strings.
3. Layout where the support post will be along the string. Then dig the holes for the footings which must be deeper than the maximum frost penetration in your area, approximately 3’, and deep enough to rest on undisturbed soil. Insert some cement about 6” then add your 4×4 support post making sure it is held plumb and in line with the string. Then add some more cement to approx 6” below grade. Then fill the rest with soil. Alternately you can fill the complete hole with cement bringing the cement to ground level and then insert a saddle to fasten your support post to.
4. Fasten 2 – 2×6, one on each side of your support posts with 6 – 3.5” nails through each 2×6 into the support post or 2 – 1/2″x8″ hex bolts. When the joist run across the top of the beam, as in this case, make sure you allow for the depth of the joist when determining the height of the beam.
5. Mark the layout of the joist on both the beam and ledger, either on 16″ or 24″ centers, as per your design. Nail the joists in place making sure that the crown is up. Now mark with a chalk line and cut the ends of the joist so they are straight and then nail on the rim joist across the ends of the joists. Don’t forget to use joist hangers on the ledger when butting the joist into the header.
6. At this point fasten the railing posts in place at equal distances around the perimeter of the deck, and on each side of the stairs making sure the spacing is no farther apart than allowed by local building codes (typically 6′, I prefer 4 -5’). We’ll do the rest of the railing later.
7. 
Fasten your deck boards to your joist with galvanized nails or deck screws making sure to stagger the joints of your deck boards so they don’t line up. Also make sure your decking boards splice on a joist at each end. You will have to notch the boards around your posts or other obstructions, leaving 1/8″ space for drainage. 5/4″x6″ pressure-treated decking may be placed with each board flush against the next; natural shrinkage will provide the proper spacing. Though with some decking material you may want to leave a nail thickness between each board. Each decking board should have two fastener (nails or screws) one on each side into each joist.
8. Let the decking run over the edge of the structure then after all boards are fastened down, chalk a line about 1” out at each edge and saw the boards off leaving that one inch overhang.
9. At this point you can build any stairs you will need and fasten them to the deck making sure you have equal rises for each step and no more than an 8” rise on each step.
10. Last but not least finish the railing by nailing the top and bottom railings to your posts and then add the balusters with a maximum of 4” centers in between. Finish it off with some caps for the posts to keep the moisture out and give it that finishing touch.
1. Purpose: First you need to decide what the primary purpose of your deck is going to be. For entertaining guests you’ll need to consider how many guests you normally entertain and therefore want the deck to hold, because that will determine its size. If it’s going to be a play area for small children then safety is a primary concern. Whatever your intended purpose, you need to fully consider it before starting to build.
3. Decking Material: You will also need to decide what type of decking material you plan to use. If wood is your choice, redwood, cedar and pressure treated pine are all popular because they resist rot and decay. PT wood will be the least expensive material to use and will last the longest but is not as nice and smooth a wood. The cost of Redwood and Cedar is about the same depending on where you live, but it is a fair amount more than PT. I do not recommend other types of wood for decks though composite decking materials are an alternative choice that has been engineered to avoid the problems of traditional wood (cracking and rotting). Vinyl is another great alternative choice instead of wood though both vinyl and composite material decks come at a premium cost, but they last many years longer then wood. 
5. Extras: The final thing to consider in the design is what extras you might want build into or onto your deck. You might want to add a decorative style handrail or flower boxes, or perhaps built-in seating for your guests, or an overhead sunscreen. Whatever extras you choose will help you to personalize your deck.