The Construction Of A Terrace: A Relaxation Area In The Sun

If you have some DIY skills, building a treated wood deck is easy, especially if you stick to a 12 ‘x 12’ square model. Let’s see what are the main stages of such a project.

A 12 ‘x 12’ terrace can comfortably accommodate the barbecue and garden furniture. If it is in the east or southeast, it is exposed to the sun during the day and enjoys the shade at supper time, which is much more pleasant. It is attached to the house on one side and rests on a floating foundation on the other end.

Start by delineating your patio with stakes and string. Measure the diagonals and make sure your square is square. The position of the foundation slabs must then be marked. The three slabs will be placed 10’6 ” in the center of the house. On the sides, place the tiles 16 ” center from the edges and drop the middle one 6 ‘from the side lines. Mark the location of the slabs with a stake.

Using your marks as a center point, dig a 2 ‘x 2’ area to a 6 ” depth. Cover your holes with a piece of geotextile membrane approximately 4ft x 4ft and fill with 3/4 ” clean crushed stone. Then fold the geotextile membrane over the crushed stone and add about 2 inches of stone dust to stabilize the slabs.

The structure

It is easier to build the structure on the ground and then lift it, secure it to the house, and keep it level with temporary posts. Use 2 “x 8″ pieces to assemble the structure. Cut your rim joists to 143 ” (11’11 ”), which will allow you to let the floor boards protrude on either side and cut off the excess afterwards. Mark the rim joists at 16 ” center to center and nail your joists to them with three 3-1 / 2 ” galvanized nails.

It may be preferable to remove the exterior siding of the house where you want to fix your terrace, for example centered on the patio door, in order to get as close as possible to the rim or border joist. from the house floor. This will reduce the length of the fasteners you will need to use (nails, screws, lag screws).


Assemble the beam with three pieces of 2 “x 8” that you will nail alternately with 3 nails and 2 nails every 8 “, in order to avoid splitting the wood. You must mark the curvature on each plank and place it upward when assembling the beam. The planks can be paired with straight pieces, but you still need to have indicated the top.

Then draw a line with a chalk line below the joists to mark the location of the beam. Check again the level and squareness of the structure; correct if necessary, using temporary posts. Slide the beam under the structure and lift it into place and secure it to the joists using nails or screws.

Measure the distance between the blocks and the beam and cut the 4 “x 4” posts to the required length; insert them under the beam and fix them securely. The three “X” posts will need to be braced with 1 “x 4” pieces. With the structure firmly attached to the house, you can finally lay out your planks and build your floor.

Spacers do not need to be used, but a 1 ” x 4 ” board is preferred under the joists in the center of the span. Make marks every 16 “on your 1” x 4 “and secure the joists by nailing them to the marks using two 2-1 / 2” nails at each joist.


To build the floor, you have a choice of 1-1 / 4 ” x 4 ” or 6 ” deck boards. You can also use 2 “x 4” or 6 “pieces. On the other hand, these create a more massive effect. The more expensive 1 1/4 “x 4” tongue and groove boards are primarily used to block mosquito entry to screened decks.

The planks should be set up with the growth rings facing up. This facilitates the flow of water and prevents the edges from curling up. Space your boards 1/8 “apart, or the thickness of a 2-1 / 2″ nail. The space between the boards will increase slightly when the wood has completely dried. 4” planks form a more even floor; 6 ” ones tend to warp more, creating unevenness from board to board. This hinders the movement of chairs and can become annoying.

With 6 ” boards, nail the boards with 3 nails on each joist or alternate 3 nails (or screws) and 2 nails (or screws) from one joist to the other. If you are using 4 ” planks, two nails all over are sufficient. Place nails at least 3/4 ” from the ends to avoid splitting the wood. Finally, the deck floor should be about 3/4 ” lower than the door sill to facilitate movement between indoors and outdoors.

The railing

For the manufacture of the guardrail, you will find on the market posts notched at the base that only need to be fixed to the edge or edge joist. In addition, their upper part is usually grooved and bevelled to create an interesting decorative effect. By adding two screws from below through the floor, you get good strength.

Several techniques apply for the installation of the handrail and the bars, especially those of the stairs. It would take too long to review them here. However, you will find pre-cut beveled bars that just need to be screwed to the crossbars. Another solution is to install sections of trellis between the posts.


Treated wood is usually guaranteed against rot for life. However, all cuts must be processed for the warranty to be valid. Unfortunately, the preservative often does not have the same color as the one used during factory processing, so we end up with a deck smeared in military camouflage style. In addition, we do not recommend painting or staining the wood the first year, since wet wood does not absorb stain well.

Related Articles

Back to top button