7 Steps for Building a Raised Deck


– Focus on Raised Decking

– Step 1: Design Your Raised Deck

– Step 2: Prepare the deck anchors

– Step 3: Attach the posts to the mounting brackets

– Step 4: Install the bastaings

– Step 5: Place the deck joists

– Step 6: Attach deck boards

– Step 7: Finish your deck

There are many reasons to choose a raised deck. The most common cause is to ensure continuity with the rooms in the house that face the outside. However, the regulations and the construction differ significantly from those for a conventional deck.

This sheet explains how to build a raised wooden deck.

Focus on the raised deck

A deck is considered raised when its level is higher than the garden because it is the outside ground that counts to define or not the elevation of a terrace. The national regulations remain vague by not specifying a height limit between raised and single-story decks. However, this limit is set at 60 cm in height in practice. However, it is advisable to consult the town hall of your municipality and the local urban planning before starting your work.

In any case, a terrace considered as raised constitutes a ground surface and requires various procedures depending on its cover:

– less than 5 m²: no application required;

– between 5 and 20 m²: request for prior authorization from the town hall;

– more than 20 m²: application for a building permit.

Good to know: a terrace on the same level, if it does not involve the construction of an awning, does not require any prior application whatever its size.

Materials needed to build a raised deck.

– Chevron

– Pencil

– Joist

– Tape measure

– Screwdriver

– Wide brush

– Fixing plates

– Outdoor wood saturator

– Jigsaw

– Lag screw

– Wood screws

1. Designing your raised deck

The raised deck does not have the same anchoring points, depending on whether it is built on a concrete slab (or any other flat, stable surface) or the natural ground. In our case, we plan to develop a 4 × 3 m terrace, i.e., 12 m², raised 65 cm above the outside ground level, on an existing or future concrete slab.

Good to know: in the case of sloping or uneven ground, the difference in height between the terrace and the immediately apparent floor is considered.

10 × 10 cm rafters act as pillars to support the deck. There will be 12 of them:

– 4 posts in the length of 4 m, spaced at 1.20 m each, in 3 rows;

– 3 posts in the width of 3 m, spaced at 1.35 m each, in 4 rows.

Four 8 × 20 cm battens will connect the posts in depth (width of 3 m) to support the joists.

Six joists of 4 m length, 4 cm width, and 2 cm height will support the deck boards.

We will use smooth and slightly curved wooden boards for this wooden deck that naturally allow rainwater drainage. They will be spaced 3 mm apart. Thus, it is not necessary to provide a slope.

2. Prepare the anchors for the raised deck

The deck is anchored to a concrete slab to ensure strength and durability. In addition, this will prevent weeds from growing through the deck boards.

Once your concrete slab is made:

– Attach 10 × 10 cm mounting plates spaced 1.20 m apart over the 4 m width.

– Attach a second and third row of plates spaced 1.35 m apart.

3. Attach the posts to the mounting brackets

Raised Deck

Position the posts in the plates.

– Cut all posts to a height of 62 cm using a jigsaw.

– Secure the posts in the mounting plates using 8 mm diameter lag bolts:

– Mark the hole markings with a pencil.

– Pull out the posts and drill on the markings.

– Replace the posts and screw in the lag screws.

4. Install the bastaings

Attach the metal support shoes

The bastaings will be attached to the posts with metal shoes. Place the metal shoes as follows:

– one shoe facing inward on each post of the first row and the last row;

– two shoes on each post of the middle row.

As before, drill and fasten with lag bolts.

Important: the shoes must be placed so that the runners attached to them are level with the posts.

Attach the battens to the shoes

– Cut the bastaings to the correct dimensions:

◦ 8 bastaings 1.35 m long;

◦ 9 bastaings 1.20 m long.

– Secure the bastaings in the metal shoes by drilling into the wood and screwing with lag bolts.

5. Place the deck joists on the raised deck

The deck joists will directly support the deck boards by choosing 4 m long deck joists (the standard length).

Attach a joist every 50 cm perpendicular to the battens. Use exterior wood screws (two at each fastening point) with a length of 5 cm and a diameter of 6 mm.

6. Attach the deck boards

Attach your deck boards to the joists:

– Choose boards that are 3 m long in one piece and 1 cm high.

– Lay the boards perpendicular to the joists with a 3 mm gap between each board.

– Fasten them to each joist with exterior wood screws.

7. Proceed to the finishing of your raised deck

Choose a clear or tinted saturator according to your taste and apply it like paint. The wood you choose is class 3 and can withstand a specific humidity level. However, using a saturator will make it more resistant to rain, spilled glass, or bare feet coming out of the pool.

After the saturator has dried, you can also apply varnish or stain in the color of your choice for aesthetic reasons.