Constructing Your Deck

The diagrams below provide basic construction details for building and waterproofing your own deck. Please consult local building codes and/or consult with a building specialist in your area for any additional construction details.

Do not install on pressure treated lumber. K-3 board, particle board and OSB are not recognized as suitable exterior sub-floor materials.


Tips to Make Your Deck a Success


Plan your deck project well ahead and make sure all materials for construction and finishing are on hand. Carefully lay out your deck area using string to be sure that it is square and level. Use the 3 - 4 - 5 squaring triangle method as shown on the construction diagrams.


Make sure your site is as level as possible. Remove all organic material from the area. If deck is within 18" of ground, a vapor barrier is required.

Attaching the Ledger

Position the ledger level at 2 1/2 inches below the threshold. You may have to remove siding to provide a flat, square surface. Take care to plan the location of fasteners and lags so they do not interfere with joist hangers. See the construction diagrams.

Posts and Footings

Review the joist/beam spacing and carefully locate the footing holes before digging. Different regions have different requirements for depth, check your local building codes. It is acceptable to use precast pier blocks and metal post connectors as described in the construction diagrams if low elevation construction. Consider burying posts for higher elevation decks.

Posts and Beams

Use a level on a string to find correct beam height to your posts. Cross check this height with a diagonal string before trimming your post. Use metal post-beam connectors if using a single beam as in beam detail D. Be sure to have adequate slope for drainage (approximately 1 inch of slope for 10 feet of deck depth).


Before attaching to ledger, sight down each joist for crown and place the crown up. Then use metal joist hanger at ledger and toe nail to beam with galvanized box nails. Be sure to maintain uniform spacing (16"). Trim joists to length, keeping in mind the width of plywood.

T & G Plywood Decking

Exterior Grade, good one side, 5/8" or 3/4" T&G, sanded one side plywood is strongly recommended. To fasten the plywood, use treated deck screws and/or galvanized nails. Angled nails provide better holding power. Set screw or nail heads just below surface. Nail or screw sheets every 6" around perimeter and 12" spacing on center joists. Stagger plywood sheets, leaving 1/8" expansion joints.

Flashing and Cantstrip

A standard 2" x 1" galvanized non-return metal flashing should be installed around the outside deck perimeter. Install galvanized metal cant strip 3/16" away from siding. Use galvanized ring nails. Nail cant strip every 12" and flashing every 6" starting from the center of the strip and working toward the ends to prevent warping.

^ back to top
  • I can honestly recommend Ducan products and by doing it myself saved nearly $5000.00 on a 450 square foot deck! Steve Anthony, Okanagan Falls, BCread more »