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No more screw heads and problems with splinters due to holes on wooden decks! Directly screwed on the joists, this system of polymer clips allows the installation of the blades without drilling or milling the wood. Its implementation however requires rigor and precision.

A wooden deck with invisible fixings

Difficulty: 2/4
Cost: 80 to 90 € about the m2 (studs, joists, clips, acacia or chestnut blades and hardware)
Time: 3 days to 2 people
Equipment: meter, level, square, jigsaw, circular with guide, miter, screwdriver, grinder with abrasive disk, drill, milling cutter, wood drills, glue gun...

The terrace is a simple, effective and economical way to expand your home and enjoy its outdoor space. Sometimes kitchen, most often dining room or living room, it allows to live outside the arrival of the beautiful days.

To succeed in your project, several factors must be taken into account: the budget, the surrounding decor, the use of the place (relaxation area near a swimming pool, dining area...) and the climate of the region.
Then comes the choice of material. Resistant to frost, weather and durable, the stone comes in the form of pavers, slabs or pebbles. Too expensive, too irregular or just too traditional, natural stone has inspired many prefabricated cement-based materials. Long-time stars, both have been competing for a few years with wood, thanks in particular to autoclaves or oils and saturators which guarantee durability and durability, but also to the arrival of exotic species such as teak or ipé, less expensive and well suited for outdoor use. Be careful, however, to favor PEFC or FSC * certified woods from sustainably managed forests.

* The Forest Stewardship Council (FSC) was established by an international NGO in 1993. The PEFC brand (Pan European Forest Certifi cation) has been in existence since 1998 at the initiative of forest owners. ** More info on: cndb.org/?p=classes_d_emploi

Which wood species to choose?

One of the major strengths of wood is the existence of classes of employment (from 1 to 5). They make it possible to classify the species in relation to their use situation, according to their resistance (or durability) to biological agents (insects and fungi).

This classification is based on exposure to water. Class 3 wood withstands rapid alternations of moisture and drying; class 4, it supports permanent immersion in fresh water, or even in seawater if it is class 5.
Other criteria to consider when buying are the aesthetics of wood and its evolution over time. Thus, the ipé retains its hue relatively well; the autoclaved pine with brown pigmentation brightened, but remains bright and warm; the classic autoclave pine or acacia become quickly greyish; the chestnut and the gray oak, while revealing brown reflections of tannin.

Attention to the quality of the bindings

With the invisible fastening system used here ("Wood Stabila Hood with Roll Clip"), the wood (heat-treated ash) is neither drilled nor milled and it is useless to measure the gap between blades.: it is done automatically.

In addition, ventilation and insulation of the blade on its support are provided by the 5 mm thickness of the base of the polymer clip. Finally, the manufacturer claims that "replacement and repositioning are possible, without having to disassemble the other blades". This does not seem to be the case for other invisible fixing systems proposed in kit. In any case, it will be advantageous to compare the prices of the different pieces supplied (the price of the clips may be low, but the price of the associated blade very high!). Also check the quality of the fixings (some become "floating" when the wood dries), if possible inquire from people with the same product installed in recent years.

Supplies

• Autoclave pine lambs
• Deck blades
• Self-tightening stainless steel screws (6 x 100 mm)
• Adjustable studs
• Kit of clips, screws and glue
• Recessed spot kit
• Geotextile felt or woven fabric

Prepare the ground to install its terrace

Prepare the ground to install its terrace

Measure the levels to evaluate the height of the terrace and provide a slope (5 mm / m) for the flow of rainwater.

A wooden deck with invisible fixings: invisible

Cover the floor with a geotextile or a woven tarpaulin to prevent rising damp and weeds. The soil should be stable and flat, if possible drained by a layer of gravel or sand (5/10 cm thick).

Fit the support frame of the terrace

Fit the support frame of the terrace

Directly place the joists (or rafters) on the geotextile. The framework will then be raised and positioned level (about 3.5 kg / ml of pinewood joists of 40 x 100 mm section).

Cut the joists

Cut the joists

Cut the joists as you mount and adapt the cutouts (around a look for example).

Drill

Drill

Drill joists of large section (40 mm) at regular intervals, using a Ø 6.5 mm wood drill.

Check before assembling

Check before assembling

Check the spacing of the joists (max. 40 to 60 cm) before assembling them.
Use a screw that is at least twice the thickness of the first penetrated part and at least 6 mm in diameter to resist tightening.

Assemble with the screwdriver

Assemble with the screwdriver

In the absence of a professional cordless screwdriver (suitable for this type of construction site), assemble the joists using a corded drill-driver used at low speed. Screwing must be done continuously.

Finish screwing

Finish screwing

Do not hesitate to finish the screwing with a socket wrench. This will be easier if you have opted for a Torx screw.

A wooden deck with invisible fixings: blades

To cut a chevron already in place, first draw a vertical cut line using a square.

A wooden deck with invisible fixings: invisible

Using a block of wood, hold the room above the ground when sawing with a handsaw.

Set up the structure of the terrace

Set up the structure of the terrace

The frame finished, position it in a summary way and simply placed on adjustable studs, first placed in each corner.

A wooden deck with invisible fixings: blades

Level the frame with the adjustable studs and check horizontality with a rule with a spirit level. Do not forget to provide a minimum slope of 5 mm / m, directed towards the outside of the terrace, to facilitate the flow of water and accelerate the drying of the wood after the rain.

A wooden deck with invisible fixings: fixings

It is possible to consider creating a step in one of the angles (also consisting of rafters and spacers). The height of a step
is mostly between 14 and 17 cm.

A wooden deck with invisible fixings: deck

In the same way as for the terrace, create a small frame to fix below the general frame of the terrace.

A wooden deck with invisible fixings: blades

Once the levels have been adjusted, screw the studs under the joists: at the rate of one stud every 1.5 m for elements of 40 x 100 mm.

Connect two joists

Connect two joists

Pre-drill (Ø 6.5 mm wood drill bit) and then screw in obliquely (6 x 80 mm screw) to join two joists (join end to end).

A wooden deck with invisible fixings: invisible

A stud is installed under each end or at the junction of the two sections.

Attach clips and lay deck slats

Attach clips and lay deck slats

For good flatness, sand the fittings with a grinder equipped with a sanding disc or belt sander.

A wooden deck with invisible fixings: deck

On each joist, unroll a roll of waterproof tape with stapled clips at regular intervals (attachment kit).

A wooden deck with invisible fixings: blades

Then fix the clips using stainless screws. Check their alignment with the ruler or the line. Some "bare" strips ensure a perfect connection between blades and joists.

A wooden deck with invisible fixings: blades

The blades are provided with two grooves on the underside, positioned on the clips.

A wooden deck with invisible fixings: fixings

Control the plumb at the bubble level.

A wooden deck with invisible fixings: wooden

Place a pad of Neoprene glue on each of the clips screwed on the joists, starting with those of the center.

A wooden deck with invisible fixings: blades

Make the nesting force. For this, it is often necessary to climb on the blades! If the site is very dirty, protect the wood with a sheet or cardboard.

A wooden deck with invisible fixings: blades

Continue the pose as before (collage and clipping). To eliminate the gap between two blades, tap the edge of the blade being laid with a wedge martyr, before having all the clips.

Install spots in the blades of his terrace

Install spots in the blades of his terrace

After marking and tracing, drill the spot housing with a Ø 20 mm wood drill bit. The drilling is done at high speed to be as sharp as possible.

A wooden deck with invisible fixings: blades

It is essential to respect the drilling diameter indicated by the manufacturer, each spot forcing into its housing.

A wooden deck with invisible fixings: invisible

Thanks to their quick connection, the spots are mounted in series. The transformer connecting them must be protected from the weather.

Attach rim boards

Attach rim boards

Cut the end of the deck blades all at once with a circular saw, guided by a ruler, for perfect alignment and precise cutting.

A wooden deck with invisible fixings: blades

The ends of the edge blades are all cut with a circular saw to be mitered. The links are clean and crisp.

A wooden deck with invisible fixings: fixings

Screw the blades in two points at each junction (each screw is embedded in the wood). Remember to insert plastic shims to get a regular gap between the blades.

A wooden deck with invisible fixings: deck

In addition to the aesthetic aspect, this space thus passes the air and plays the role of expansion joint. Between the boards and the existing frame (walls, posts...), provide a space of at least 10 mm.

Lay a harmonious look lid

Lay a harmonious look lid

The concrete cover of one look can be concealed or cleverly replaced. For this, two sections of blades are screwed on cleats leaving an expansion joint (on a section, the position of a duct has been reported and cut).

A wooden deck with invisible fixings: fixings

The set is then simply laid. For an even more discreet cover, the sections are cut beforehand in the two aligned blades (thus, the ribs of the wood extend) and screwed from below.


Video Instruction: Composite Decking - Perpendicular Installation