Level of Difficulty: Intermediate Do-It-Yourselfer – Moderate
Completion Time: Week-end Project
Building a one-level deck or patio is a great way to increase the living space of your. It is the ultimate do-it-yourself job because building a 12" X 12" one-level deck or patio can be achieved in one weekend by just following a simple set of instructions. Decking material is available in pressure-treated wood, cedar, composite wood and plastic and vinyl. This choice can be factored by the use and cost of the deck or by the yearly climate. To get the best information for the right deck material talk to an expert.
This project uses treated wood but you can use composite or cedar as well. Just remember that the structure that holds the deck as to be built with treated wood.


  • Carpenter’s level
  • Chalk line
  • Circular saw
  • Drill bit
  • Hammer drill
  • Garden hoe
  • Measuring tape
  • Pickets
  • Plumb line
  • Shovel
  • Carpenter’s square


  • Anchoring screws
  • Bags of pre-mixed concrete (or 18 concrete patio slabs)
  • Cylindrical forms (Sonotubes®) or 4" deck blocks if using patio stones
  • Galvanized 4" post saddles (if using concrete)
  • Carriage bolts, nuts and washers
  • Galvanized joist hangers and brackets
  • Galvanized screws and nails
  • Lag screws and washers
  • Reinforcing mesh (if using concrete)
  • Reinforcing wire (If using concrete)
  • Galvanized flashing or drip cap
  • Caulking
  • Treated wood (beams, posts, ramps, steps, lattice, decking)



Treated wood should be handled with precautions.

  • Wear gloves and long sleeves when handling treated wood to avoid skin contact with and to protect against splinters.
  • Wear dust mask, eye protection, gloves and long sleeves when sawing, sanding or shaping treated wood to avoid skin contact with or inhalation of sawdust, to protect against splinters and to protect eyes from flying particles. When making cross cuts use a cut sealer as the factory-treatment rarely goes to the heartwood.

During construction:

  • Apply an appropriate “end-cut” preservative to protect exposed, untreated wood.
  • Use nails, screws, bolts, connectors and other hardware resistant to corrosion: stainless steel, hot-dipped galvanized, yellow zinc or specially coated for outdoor use. Ordinary fasteners will rust, causing unsightly stains, and will weaken and fail.
  • Make certain the wood is thoroughly dry before painting or staining, and follow the coating manufacturer’s recommendations. Use only good quality oil or acrylic coatings on water repellent pressure treated wood.
  • Regularly apply a stain or a water-resistant product to waterproof the wood and reduce leaching: every two years on floors and every four years for all other surfaces.
  • Do not dispose of treated wood remnants or sawdust in compost heaps, wood chips, or mulch and do not use it as animal bedding or litter.
  • Never burn treated wood.


The National Building Code of Canada establishes guidelines for the construction of buildings and various structures, including decks. However, these standards can vary depending on the local building requirements in effect in a particular province or municipality.
The height of the deck’s surface above the ground determines the requirement for the railing height

  • Deck height under 24" = Optional or decorative railing
  • Deck height from 24" to 5" 10" = 36" railing
  • Deck height over 5’10” = 42" railing

Also Note:

  • The maximum distance between the balusters and under the bottom rail is 4".
  • For a stairway, the treads should be no less than 9 ¼” deep and the risers no more than 8" high.

    Always check the local building requirements for your area before beginning any such construction project.


1.1. Trace the perimeter of the deck onto the ground area using string and wooden stakes sharpened at one end.

1.2. Run the string from the house to the end of the intended deck so that it is perpendicular to the house using the 3 – 4 – 5 rule: measure 3′ on one side, 4′ on the adjacent side and the diagonal measurements should equal 5′.

1.3. Multiple these values to increase the size of the deck.

2.1. Remove the grass within the delineated perimeter with a garden hoe.

2.2. Cover the area with a geotextile sheet over the space to prevent weeds from growing in the space.

2.3. Coat the area with a 1″ to 2″ coat of gravel.

There are four types of foundations for your deck: concrete pillars with footings, concrete pillars without footings, concrete blocks, screwable foundation posts. Building a deck above 24″ in most areas of the country requires a concrete footing with galvanized “saddles” to hold the support posts. From the standpoint of construction stability, a foundation with a footing is suggested.

3.1. Concrete pillars with footings require a concrete footing or wide pad below the frost line (in most areas this is 4′. The concrete pillar is attached to this pad with steel reinforcing rods. The saddle is embedded into the top of the pillar. This is the required method for larger decks where weight is a consideration.

3.2. Concrete footings without pads require digging down below the frost line and pouring concrete using a cardboard tube or a form. S0teel reinforcing rod is placed in this tube before pouring to add strength. The saddle is embedded into the pillar.

3.3. Screwable foundation posts require softer soil. With a long stem shaped like an auger these posts are literally screwed into the ground until the saddle is ground level. Then the 4″ treated post is bolted to the saddle.

3.4. Concrete blocks on patio stones are an easy idea for a deck that is ground level. This provides a footing to keep the blocks from sinking.

Install the ledger board (usually a 2″ X 10″ pressure-treated board) on the area of the home where the deck will be built will not only add structure to the deck but provide the height standard.

4.1. Level the ledger board and make sure it is at the height of the interior floor before fastening

4.2. Cut the ledger board and end joist beam (usually a 2″ X 10″pressure-treated board) to the length required for the deck measurements. (In some cases, an end joist beam is laminated to the ledger board for support. For small decks this may not be needed.)

4.3. Drill holes in the ledger board to receive the lag bolts (These are usually 3/8″. The ends of the board should have a top and bottom hole and then the holes are alternated from top to bottom along the whole length.

4.4. Place the ledger board against the wall exactly where it’s to be installed. To make sure it stays level use shorter pieces of wood to prop it up.

4.5. Mark the siding underneath by inserting a marker pencil or pen in each hole. Take down the ledger board.

4.6. Drill into the concrete or brick surface with a hammer drill using a larger bit so that lead anchor plugs can be installed.

4.7. Pound in the lead anchor plugs in the holes making sure they’re flush with the wall.

4.8. Screw the lag bolts into the holes in the end joist beam but just to get them started. Make sure there are washers on each bolt.

4.9. Raise the ledger board against the wall and bolt it into place.

4.10. Caulk the top of the end joist beam and install the dripcap so that the top of the cap is preferably on a mortar joint. The mortar joint can be shipped out so that the top of the dripcap can be tucked in. Then this can re-mortared to seal it. Then no water can get behind.

5.1. Cut the ledger board (2″× 10″ beam) to the required length. (In some cases an end joist beam is laminated to the ledger board for support. For small decks, this may not be needed.)

5.2. Drill holes in the ledger board to receive the lag bolts (These are usually 3/8″. The ends of the board should have a top and bottom hole and then the holes are alternated from top to bottom along the whole length.

5.3. Place the ledger board against the wooden clapboard exactly where it’s to be installed.

5.4. Trace the perimeter of the ledger board.

5.5. Adjust the blade of the circular saw to ½” or less depending on the thickness of the clapboard of the home. For concrete-based clapboard use a blade recommended by the siding manufacturer.

5.6. Cut a strip through the clapboard along the traced lines. This will give you access to the house end joist beam to which you will attach the deck ledger board.

5.7. Cut a drip cap the length of the ledger board.

5.8. Caulk the drip cap in place making sure the top tab is slid under the siding.

5.9. Install the deck’s ledger board against the house making sure it is level.

5.10. Mark the part of the house where the joist in required by inserting a marker through the terrace end joist (part of the house’s sill) bolt holes where required.

5.11. Remove the ledger board.

5.12. Predrill holes in the exposed ribbon joist to accept the lag bolts.

5.13. Bolt the ledger board in place against the home using galvanized washers.

5.14. Make sure the drip cap is on top of the ledger board. Caulk top of ledger board to avoid water infiltration between the drip cap and ledger board. Use only galvanized steel and not aluminum as aluminum will react with the chemicals in the pressure-treated lumber and corrode.

This is the preferred design if the lower deck is above the ground. For ground level the beams can be placed in concrete deck blocks.

6.1. Put in place either deck blocks or poured concrete supports (depending on the height). This sturdy support will be placed on the 4″ X 4″ beams attached to the concrete piers with post saddles.

6.2. Laminate two 2″ × 10″ beams together to make the support girder. This sturdy support will be attached to the post with post saddles.

6.3. Place the girder lower than the ledger beam by 1/8″ per foot to allow for adequate water runoff. On a 12′ X 12′ deck this would be a 1 ½” drop in height.

Install joists perpendicular to the house at 16″ centres to the ledger using joist hangers.

7.1. Cut the joists to the required length. This step can be simplified by buying 12′ joists and no cutting is required because the lengths will fit the frame.

7.2. Level the end joist and attach it to the ledger using joist hangers. Let the other end lay on the girder.

7.3. Laminate a second joist to the first for strength.

7.4. Attach the laminated joists to the girder by driving nails at a 45° angle on either side.

7.5. Attach single joists with joist nails or special brackets. These should be placed in 16″ apart at the center.

7.6. Attach a rim joist (or ribbon joist) to cover the ends of the joist set in place and serve as a brace. In a 12′ X 12′ deck this should be the same size and material used for the deck joists. Drive at least two nails at the end of every joist.

Decking material is available in pressure-treated wood, cedar, composite wood and plastic and vinyl. This choice can be factored by the use and cost of the deck or by the yearly climate. The following instructions are for installation of a solid wood decking. Other types of decking may require different methods of installation requiring special hardware. As with the joists, when buying deck boards get them the same size as the deck to avoid cutting and wastage

8.1. Install a first deck board flush with the ribbon joist. Use treated deck screws or galvanized nails.

8.2. Lay down the deck boards for the entire deck using nails as spacers. (Some prefer placing the boards tight against each other as they will naturally shrink and leave spaces)

8.3. Adjust the spaces so as to cover the entire floor surface without having to rip the last board against the house.

8.4. Attach deck boards to the joists using screws or galvanized nails. Use two per joist. Pre-drill the ends to reduce splitting.

8.5. Remove spacer nails.

8.6. Attach pressure-treated 1″ × 8″ pieces of lumber around the deck close to the ground. They will be required to attach the lattice frame that hides under the deck.

This option takes a practiced eye because they are custom cut but it is cheaper and the height can be customized.

9.1. Divide the height in inches of the deck by 7 to determine the number of steps needed. Round off to the nearest number.

9.2. Dividing the height between the two levels by the number of steps determined in the previous calculation to height. If the figure so obtained exceeds 8″, add one more step and redo the last calculation. In some areas the building code requires that each set of stairs requires 3 stringers.

9.3. Trace the steps and risers on 2″ × 10″ beams using a carpenter’s square in the required length.

9.4. Cut out the waste material from the stringer using a circular saw. Use a handsaw to finish the cuts as the circular blade will not reach all the way in.

9.5. Use the first stringer as a template to cut the second.

9.6. Attach the two stringers with stair brackets. (In some areas the building code requires 3 stringers)

10.1. Choose pre-cut closed stringers with steps that are 7½” high. The following calculations will help you buy the closed stringers you need.

10.2. Measure the distance that separates the top of the joists from the ground using a measuring tape and plumb line. Convert into inches. The remaining fraction will be used to determine the thickness of the concrete step at the bottom of the staircase.

The measurement to the top step, in keeping with the height of the deck, is made from the form where you’ll pour the concrete.

11.1. Dig a rectangular trough 4″ deep.

11.2. Build a box made from 2″ X 6″ lumber to act as a form and place in the trough. Level the box.

11.3. Lay two reinforcing rods lengthwise at the bottom of the hole and cover them with metallic lath. This will avoid cracking.

11.4. Calculate the square footage of the concrete base to find out how many bags of concrete mix will be needed.

11.5. Mix, pour and level the concrete for the pad.

11.6. Let dry and remove the form.

11.7. Attach à 2″ × 4″ piece under the end joist of the terrace. To guarantee a solid base for nailing, be sure the 2″ × 4″ is at least 4″ wider than the stringers on either side.

11.8. Attach the top of the closed stringers to the 2″ × 4″ piece with angle iron.

11.9. Lay the base of the stringers to the bottom step.

The height of a riser varies between 7½” and 8″. That half-inch margin is necessary for the perfect adjustment of the staircase. That is why you need to add the remaining fraction from the preceding calculation to the theoretical height of the concrete step (7½”.). This way you’ll get the actual depth of the concrete step.

12.1. Cut 2″ × 6″ boards to the required length. (The steps are usually 2″ wider than the space of the two stringers.) This will help stabilize the staircase.

12.2. Drive two screws through each step into each stringer.

13.1. Attach special brackets to the deck floor to secure the 4″ × 4″ posts for the railing. Leave a 2″ space between the brackets and the house siding.

13.2. Install the upper and lower rail with special railing brackets. The railings can be made from 2″ × 4″ or 2″ × 6″ lumber.

13.3. Mark off the railing every 4″ centre to centre for baluster placement.

13.4. Predrill then screw balusters to the top railing.

13.5. Level balusters then predrill and screw to them to the lower rail.

14.1. Install 2″ × 4″ boards around the bottom of the deck to provide a base in which to nail the lattice. At the front of the deck, the posts can serve as a nailing base.

14.2. Attach 2″ × 4″ boards vertically along the foundation walls as well.

14.3. Cut your lattice to the required size.

14.4. Use grooved rails, which you will cut at 45° with the help of a miter box and attach to the posts and rails through the groove with deck screws.

14.5. Install the pre-cut lattice mouldings at a 45° angle around the trellis and attach to the base you have just built..