Adding a deck is one of the most useful projects a homeowner can do to improve their home.   Each deck is different and presents it's own set of challenges, so contact us with unique questions if they are not covered here.  We are building a 12' x 24' beck with "clipped" corners and lattice installed below.  

Check with your local building code enforcement office for specific material requirements in your area .  For instance, the footer requirements vary greatly in different areas of the country, and you will need to know your local requirements. 

Certain assumptions are made with deck building.  1. Use appropriate lumber such as pressure treated yellow pine, redwood, or others designated for such work.  2. Use galvanized nails, nuts, bolts, and screws.

Step1 - Install ledger board on house as shown.  Remove siding material if necessary to place your ledger board directly on the sheathing. If siding material is masonry you will bolt the ledger board directly on the surface of the brick or block. Ledger board will normally be the same size as the joists you are using.  In our project a large ledger board was installed previously to cover the area below the door until the deck could be installed.  

 

Determine length of deck, cut and nail ledger board directly to sheathing or brick  veneer. Drill 1/2" holes every 16"  through ledger board and house floor joists.  Install with 1/2" x 8" galvanized nuts and bolts with washers and tighten securely. 

Step 2 - Measure and install joist hangers every 16".  See Figure "B" above. Fill every hole in each joist hanger with nails or screws. Joist hanger nails are also available at your local home center.

Figure "A"  is the flashing placed behind the siding to go on top of the decking boards to keep rain from washing behind the ledger board.  

 

Step 3 - Locate and install footers to hold deck. This is best planned with information provided by your local building code enforcement office.

They will provide the following:

  • How many footers will be required for a deck your size.
  • How deep to dig to stay below the frost line.
  • Thickness of solid masonry footer (usually 8").
  • Minimum length and width (footprint) of the footer.

Our project used footer blocks which can be purchased at your local home center.  A string is used to assure all footers are in line.

Footer placement will be determined by the length and width of the deck.  Part of determining footer location is to square up the area where the footers will be placed. 

 

If your deck is  24' long by 12' deep with cantilevered joists, your footer line will be 10' out from the house. Place two stakes in the ground 10' out from the house that are 24' apart. Diagonally measure across this 10'x24' rectangle to determine the squareness of this work area. Adjust the stakes left or right (staying 24' apart and 10' from the house) to make your work area a true rectangle with 90 degree angles. When you have both diagonal measurements equal, your work area is square. This is the line for your footers to be placed in.  If you are cantilevering your main beam as well, measure in 24" from each end and then calculate the number of additional footers needed to cover the distance left.By cantilevering floor joists over main girder as we have done you can have a stronger deck and can use smaller lumber. Check below for some general guidelines as to lumber specs and deck construction.

 

General Lumber Guidelines:  (Check your local building code for requirements in your area) 
  • Pressure treated lumber (.40cca and above) can be placed on or below the ground. In other words your footer does not have to reach above the ground as ours did to keep the lumber above grade.
  • Double 2x10 is the normal main girder (beam) on deck construction. Larger lumber can be used to span longer distances between footers.  
  • Double 2x10 pressure treated SYP (Southern Yellow Pine) can normally span approximately 8 feet between supports.  (See "D" to "B" below) 
  • Deck joists can be cantilevered approximately 24" past main girder.
  • Main Beam can be cantilevered approximately 24" past each end column support (See "E" below) Cantilevering the main beam frequently allows for fewer footers and upright column supports, while making the deck just as strong.
  • 2x8 SYP treated joists will span approximately 12 feet. With cantilevering you could build a 14 foot deck with 2x8 joists.
  • 2x10 SYP treated joists will span approximately 14 feet, allowing a 16 foot deck with cantilevered joists.
  • Vertical column supports can be 4x4 material up to a length of approximately 4 feet. For lengths longer than 4 feet between footer and bottom of girder beam (location "C" below) , use a 6x6. 

 

Step 4 - Assemble main girder beam to cover the length of the deck (same length as the ledger board you fastened to the house). Stagger the seams in the two piece girder so they are over top of a column support (location "B").  Drawing below shows staggered girder joints.

Step 5 - Determine the height of the column supports ("C") by installing 2 joists. Install and nail one joist in each end joist hanger on the ledger board that is in-line with the two end footers. Place a level on top of first joist at point "A" and raise that joist until it is level. Nail a temporary column support at the end of that joist, holding it in place. Repeat this for the other end joist. Measure the distance from the top of your footer to the bottom of each joist. Subtract the thickness of your main beam (9 1/4" for a 2x10 beam). This will be the length of your vertical column support. Nail a guide (see location  "D" on figure above) to side of vertical column to hold main girder in place and in-line during assembly.
 

Fasten main girder to vertical columns with guide (location "D") and lift into place. It should come up under the two joists used earlier for measurement.  Square up, plumb columns and toe-nail these two joists to the girder to hold in place. Toe nail these two joists in their correct location by mirroring the joist locations on the ledger board.  Measure and add any additional vertical columns. Temporarily brace this structure with diagonal 2x4 braces on the vertical columns.  Now your ready to start installing deck joists.

 

 

 

 

 

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