How to Build a Deck Yourself
Few home improvement projects add more value and, to be frank, enjoyment to your home than a well-built deck. An evening barbequing with friends, a midday outing without scraping dirt off your shoes, or simply a few minutes looking up at the stars-the possibilities are endless, and the utility of a good deck is hard to beat.
Unfortunately, adding a deck can be a pretty costly endeavor. In the United States, an average 10 by 20-foot deck costs in the neighborhood of $14,400, with close to 75% of the cost going into skilled labor.
On the other hand, the 2017 Remodeling magazine report showed that an average home recouped 106% of the cost of adding a deck when selling a home. A homeowner doing their own labor will generate over 11,000 dollars in profit from the deck at the time of sale.
Looking at the numbers, it's clear that a homeowner willing to roll up his or her sleeves and put some sweat equity into building a deck will not only gain a new favorite place to relax but will generate a chunk of equity to add to the value of their home.
Let's take a look at how you can build a sturdy, beautiful deck of your own.
Home Deck Design and Layout
For most of us, the design decision starts with clearing our project with your city's building department and HOA. Make sure that it does not run against their rules to avoid issues later. Deck design, while technically not part of the house, still has to meet the requirements of the building code.
The shape and size of the deck are completely dependent on how you plan on using it, the size of the furniture you'll have on it, and the number of people you plan on accommodating it.
It pays to take into account the size of the materials you'll be using- it can be a huge time saver. Most wood or composite deck boards are 5 1/2 inches wide, plus 1/8 inch spacing- designing the deck in 5 6/8 increments will save you from cutting and having to use a partial board (which never looks good and is always a pain to attach).
- Is the deck you're building going to be freestanding or attached to the house?
- If it's attached to the house-is the surface going to be level with the room you're walking out from, or will you need to add steps?
- Is your deck going to be positioned low, like a slightly raised patio, or will you lift it level with the second story of your house?
The possibilities are endless, but the principles of deck design and construction stay very much the same.
A well-built foundation is the least noticeable yet easily the most important part of your deck design. A misplaced post or a board can be removed, fixed, or replaced- a post that sinks or moves thanks to a foundation that's not doing its job can be the end of your project.
Today there are a number of foundation designs that are used for deck construction:
For a concrete pier, a form, usually a round, 12-inch cardboard sonotube, is buried to depth and filled with concrete. The most common method to build a deck foundation.
Post and Footing
For this approach, a concrete footing is poured, and a treated post, instead of being attached to the pier, is connected directly to the footing.
Pier and Footing
A larger footing is poured for this style, with rebar sticking out to connect the pier, and then a pier is poured on top. Usually used to distribute the heavy weight of a large deck in an area that does not have room for multiple piers.
This is a precast block of cement that's set on the tamped gravel and supports the deck directly. Not buried and is only useful for low decks not attached to a permanent building.
On this project, we'll go with a concrete pier since it's the easiest design for a DIYer and will work for both freestanding and attached deck designs.
Start by looking up the average frost depth in your area-your footing should fall below that level. You'll be able to find a frost depth using your zip code, or a quick call to your building department should furnish you with that information.
A shallow foundation will allow water in the ground to freeze and saw below it, moving the post up and down as it does so, destroying the deck built on it. Water, as it freezes, generates amazing amounts of force, routinely cracking house foundations that were not dug in deep enough.
To calculate the number of posts you'll need to support your deck (and the footings to support those posts), you can look up the span(maximum distance between supporting points) of the type of wood you're planning to use (or use the American wood council span calculator) or just go with a golden rule of 8 ft of span per post.
- Clear off the area you've designated for your deck.
- Using batter boards and string, mark out the perimeter of the deck and post locations.
- Give 811 a call to make sure you're not digging into a utility line.
- Use a post-hole digger and a shovel, an auger, or a rotary hammer drill with an auger attachment to dig out the holes for the footings. Go a few inches below the frost line, but be careful not to disturb the soil below. Loose soil will have to be tamped down to avoid settling when the weight of the footing is on it.
- Dump a couple of inches of gravel into the hole and tamp them down carefully.
- Place the sonotubes and level them 1-2 inches above ground level. Use scrap lumber to secure them in place. Backfill around the tube with excavated dirt.
- Mix the ready-mix concrete in a wheelbarrow or a concrete mixer. The amount of water needed will be on the package of premixed concrete, but it's also affected by the temperature and humidity. Always err on the side of less water-too much water will result in weaker concrete and cracks.
- Fill the tubes with concrete and level the tops.
- Insert post anchors into wet concrete and level them, aligning the anchors using the string you ran between the batter boards.
- Give the footings enough time to set-it takes concreted decades to fully harden, but most mixes should be hard enough to work within a day or two.
The deck structure is a modified timber frame design, called post and beam, replacing the intricate joinery with metal hardware and shoulder joints. It retains most of the strength of the traditional design but cuts the amount of time and skill it takes to complete the project.
Most deck frames are built from dimensional lumber, with 4 by 4s and 6 by 6s commonly used for vertical posts.
- The first step in building a frame will be setting posts into the post anchor hardware. Position the post in place, use scrap lumber and a level to make sure it is perfectly vertical, and attach it to the hardware with screws or the bolts that come with it.
- If your deck is attached to the house, this is the time to attach a ledger board. Locate the house rim, mark the future location of the ledger board, and remove the siding in the area. Make sure to account for the thickness of the decking you'll be using.
- Place flashing behind the ledger board to deflect the water from flowing behind the ledger board and attach it to the wall using 1/2 or 1/4 lag screws, 2 per each foot. You can also use construction bolts going all the way through the ledger board and rim if you have access to the area behind the house rim to righten up the nuts. Keep the fasteners you're using more than 2 inches away from the edges of the ledger board.
- Attach the beam (or beams if your deck is freestanding) to the posts using metal posts and beam hardware. If you're assembling your beam from multiple two by 10 or 12 pieces of lumber, laminating them in place will save the effort of attempting to lift a heavy beam into place. If the deck you're working on is low, patio-style, set the beams directly on the piers and attach them to the hardware. Use a laser level to make sure the ledge board and the top of the beam are exactly level.
- Install rim joists to complete the perimeter of the deck using galvanized through-bolts or lug bolts. Add angle brackets or other hardware that's required by the building code in your area.
- Cut the posts flash with the deck structure unless you're planning on using them as part of the railing support.
- Mark spacing for the joists on the inside of the beam and the ledger board or the two beams on a freestanding deck. The common spacing is 12 or 16 inches on the center (centerline of the piece of lumber you're attaching).
- Cut the joists to length and crown them—pick the side with the curvature facing out. All boards will have a slight curvature that you can see if you set one end on the dirt and look down the length of the board- it's important to place them all with the crown, the curve facing up, towards the future decking.
- Attach the joists using galvanized 3-inch nails or screws.
- Install and connect to the beams and ledger board joist support hardware.
When it comes to decking, you'll have to decide between natural wood boards and composite or treated wood. The main advantage of composite decking is that it's almost completely impervious to the elements. The downside-almost double the cost.
Treated wood is soaked in DCOIT (3(2H)-isothiazolinone, 4,5-dichloro-2-octyl), making it able to withstand the ravages of nature but exposing you to the effects of toxic chemicals if your skin spends a significant amount of time in close proximity to treated wood.
- Start laying the boards out from the side of the deck away from the house (on a free-standing deck, you can start from either side), laying boards perpendicular to the joists and parallel to the house.
- Attach each board with two deck screws positioned 3/4 inch from the edge of the board. Maintain 1/8 inch spacing between the boards (as the boards dry, the space in between will expand) to allow rainwater and melting snow a path to escape from the surface of the deck.
- Once you're so close to the house walls that a full deck board is not going to fit, cut the final board to size and attach it using two fasteners per joist.
- Once all decking boards are in place, snap a straight line a couple of inches outside the rim joists and cut the boards to length with a circular saw.
Building codes in most locations require the minimum height of the railing to be no less than 3 feet tall and the maximum space between parts of no more than 4 inches. Codes aside, a set of taller railings is a pretty good idea to keep you and yours from tumbling out-especially if you're building a deck that's up on the second story of your home.
- Start with marking the spaces for your railing and posts-try to keep them evenly spaced and no further than 8 feet apart.
- Cut rail posts to length, allowing for at least a 6-inch overhang.
- Cut out a shoulder joint, with the shoulder 1 1/4 inches deep.
- Attach the rails to the deck, using 2 1/2 inch through-bolts per post.
- Using a string with a level or a laser level, cut all posts to the same height.
- Cut rails, 2 per each space between the posts, the same length as the distance between the railing posts.
- Cut pieces of 1 by 3 lumber, 2 per each space between the posts and the same length as the rails.
- Cut pieces of 2 by 2 to the length equaling the height of the rail minus 3 1/2 inches.
- Place the pieces of 2 by 2 (balusters) on the 1 by 3, spacing them 2 inches apart, and attach using a drop of outside wood glue and a screw.
- Predrill screw holes in the rails at a 45-degree angle (a pocket hole jig comes very handy here) and attach the rails to the rail post.
- Position the baluster assembly on top of the rail and screw it down.
- Place the second rail on top of the baluster assembly and screw it down to the rail post and assemble itself.
With your brand-new deck finished, it's time to put a bit of effort into ensuring it can stand up to the engine of destruction we lovingly call mother nature.
When it comes to deck finish, you have two options- a deck sealer and a deck stain.
Both will seal the surface and protect it from water penetration. A deck sealer will do so while preserving the natural color of the wood, while a deck stain will add a color pigment. Deck stain, especially if you pick a darker color, will help the wood withstand UV ray damage as well.
- Start by cleaning the deck surfaces, paying special attention to glue and oil drips.
- Check the weather forecast-most stains and sealers have to be applied when the temperatures are above 55 degrees Fahrenheit and need at least a couple of dry days to set.
- Sand the deck to remove imperfections and open up the wood pores for easier absorption of sealant.
- Stir the stain or sealant you're using and apply it to the deck using a brush, paint roller, or paint gun.
- Apply a second coat if needed or to increase protection.
- Give your new deck a few days to dry.
Building a sturdy, good-looking deck that'll be an envy of the neighborhood is completely within the grasp of a DIYer. A couple of weekends of digging, cutting, and nailing, and you'll be kicking your feet up and cracking open a cold one on your brand-spanking new deck.