5 Steps to Install Composite Wood Deck

Contents

    – Step 1: Define your composite decking project

    – Step 2.0: Install the joists on a concrete slab

    – Step 2.1: Install the joists on a natural floor

    – Step 3: Install the first row of deck boards

    – Step 4: Install the next row of boards

    – Step 5: Finish the composite deck by installing the edge boards

As soon as the warm weather arrives, the deck becomes a real additional living space. As a link between the house and the garden, it is a pleasant place to relax and have lunch or rest. Composite wood has many advantages: it is light, easy to install, and durable over time, without requiring maintenance. You can install the composite deck on a concrete slab or a natural ground. Follow these detailed explanations to learn how to install a composite deck.

1. Define your composite decking project

Choose the location of the deck

    – Choose a location near the house for convenience.

    – If your deck is not attached to the house, make sure it is accessible through Japanese steps or graveled paths.

    – Orient your deck to the south or west to get maximum sunlight.

Good to know: avoid a north-facing orientation to avoid having a damp, cold, and dark terrace.

    – A terrace facing the wind is not very pleasant, but it is possible to remedy this problem by planting a hedge or wooden fences.

Determine the size of your deck

Think about how you will use your deck to determine its size.

    – For a family dining area with a table and chairs, 10 to 15 m² is sufficient.

    – For a relaxation and reception area, plan for at least 30 m².

Draw a plan for your deck

    – Choose the shape of your terrace, L-shaped, rectangular or rounded, according to your tastes but also the configuration of the garden.

    – Draw a plan on paper, noting all dimensions.

Good to know: make a view of the garden to visualize your project better.

Determine the type of deck support

You can install a composite wood deck on natural soil or a concrete slab.

    – If you already have a concrete deck, use it as a base.

    – If your substrate is natural soil, follow the recommendations for installing a deck on natural soil.

2.0 Install the joists on a concrete slab

With a concrete slab, the joists are fixed directly on it.

Place the 2 joists perpendicular to the house

    – Place 2 joists of the same size perpendicular to the wall of the house.

    – Insert an expansion block between the joists and the wall.

    – Make sure that they are square.

Attach the 2 joists

    – Drill a pilot hole at both ends of the joists, then every 70 cm or so.

    – Countersink the screw heads using a larger drill bit.

Good to know: do this operation carefully so that the screw heads do not protrude from the wood. 

    – Drill the slab through the joists with a concrete drill bit.

    – Then, insert knockout dowels into each hole to secure the joists.

Place and fasten the intermediate joists

    – Place the intermediate joists every 30 to 40 cm.

    – Check that they are horizontal and square.

    – Attach the joists as before.

2.1 Install the joists on a natural floor

Before installing the joists, prepare your natural floor to obtain a horizontal deck at the desired height.

Prepare the ground

    – Mark out the decking area.

    – Place a geotextile film on the ground, covering the entire surface.

    – Place a bed of sand on the film.

    – Pack it down over the entire surface with a roller.

    – Place concrete slabs at each corner, then distribute them evenly. They will serve to stabilize the joists.

Good to know: you can replace the concrete slabs with adjustable blocks. To fix the joists to the blocks, refer to the instructions provided.

    – Check the level of the whole by placing a mason’s rule on the slabs and a spirit level on it. If necessary, adjust the level by adding sand.

Install the joists

    – Assemble a frame of joists around the deck by screwing them together, edge to edge.

    – Double the 2 sides by laying 2 joists, one against the other, on the sides where you will lay the first and last row of boards.

    – Check the squareness of the frame by measuring the diagonals. They must be identical.

Good to know: with a string, take the length of the first diagonal. Then check that the second diagonal is the same length.

    – Install the intermediate joists inside the frame, approximately every 30 to 35 cm.

3. Install the first row of deck boards

Place the first board on the joist

    – Place the first decking board in perfect alignment with the joist.

    – Insert a shim between the wall and the joist to allow for expansion.

    – Then screw the board into the joist. – Drill pilot holes and countersink the screw heads.

    

Insert fasteners and continue the installation

    – Insert the fastening clips into the board’s groove, centering them on each joist.

    – Screw the clips lightly (without locking them) into the joists.

    – If necessary, complete the installation with another board up to the end of the deck.

Caution: the board joints must be in the middle of a joist.

4. Install the following rows of boards

    – Place a board in the second row along the first row.

Note: If the side of the deck is against a wall, insert a shim between the wall and the board.

    – Insert the clips into the board’s groove and snap them into place.

    – Continue installing the second row in the same way, making sure to position the board joints in the middle of a joist.

Good to know: if you want to install the boards with staggered joints, mark the distance needed to reach the middle of the joist and cut the panel to the correct size.

    – Once the line is installed, adjust the alignment of the boards by tapping on the end of the line and the side with a mallet.

    – Then screw the clips completely onto the joists.

    – Install the other lines in the same manner.

5. Finish the composite deck by installing the edge boards

    – Measure the height of the deck, then subtract several centimeters to allow for rainwater drainage and air circulation.

    – Transfer this measurement to the width of the boards and cut them to remove the grooved side. This will give you a clean edge with no grooves.

Good to know: if several sides of the deck are to be covered, cut the end of the boards at a 45° angle using a miter box to ensure a perfect finish to the corners.

    – Screw the edge boards into the joists.

Your deck is finished, and you can enjoy it as soon as the first rays of sunshine arrive!

Materials needed to install a composite deck

Miter box

Wooden wedge

Hammer dowel

Carpenter’s pencil

Square

Milling cutter

Beam

Carpenter’s mallet

Tape measure

Spirit level

Shovel

Drill

Percussion drill

Mason’s rule

Arm roller

Sand

Circular saw

Hand saw

Wood screws

Screwdriver