In addition to the manufacturers fixing instructions (shown below), the
following notes highlight specific guidance from Metsä Wood:
Wood Composite deck boards are subject to expansion and contraction when
exposed to variations in temperature. To accommodate for this potential thermal
- Allow a 30mm expansion gap around the perimeter of the deck giving consideration to all walls, posts and other obstacles.
- Allow a 10mm expansion gap between the ends of boards
- To prevent ‘creep’ secret fix each board with a single screw, positioned half way along its length, angled at 45 degrees and fixed through the bottom lip of the groove and into the joist or bearer below.
• To aid water run off prepare the sub-frame to
accommodate a fall of 2mm per metre along the length of the deck boards.
Fix joists/bearers at a maximum of 40cm centres when boards are fitted
perpendicular to the joist direction. When boards are fitted diagonal to the
direction of the joist/bearer provide supports at 30cm centres.
• If the deck
is to be raised or used for commercial use, seek guidance from a qualified
engineer to ensure the structure is sufficient to carry the potential
Composite Decking – Manufacturers Fixing Instructions
laying: Preferably to be used on a hard sub-grade. In case of use directly on
garden soil always place paving stones underneath the rails to create an extra
strong foundation (see image 1). In that case level the ground first and remove
possible weeds and use a black anti-weed membrane to prevent as much as possible
weeds from growing. Keep a minimum gap of 30 mm between decking / rails and
walls or other obstacles. In order to absorb the longitudinal effect of the WPC
decking by influence of temperature changes, please keep an opening of about 10
mm between the crosscut faces in case of use of several sections of decking in
the longitudinal direction of the terrace. Use a fine-toothed saw for cutting
the material to size.
Step 1: Lay the rails (base structure) flat and level (see
image 6), at a maximum interval of 40 cm.
decking 2-3 cm longer and cut to size after installation, using a circular saw.
Then fit the finishing profile. This will give it a very neat finish.
Step 2: Place a finishing profile (A-vertical) against the
head of the rails (A-horizontal), see image 2. Cut this finishing profile with a
false mitre. Note: follow the drawing (see images 7 and 8), so that the
finishing profile connects with the so-called crosscut face later. This too must
be done exactly according to the drawing (see images 7 and 8).
Step 3: Now install the first section of decking (B). Make
sure that the tongue of the finishing profile and the groove of the decking
interlock and connect correctly. Now screw the finishing profile to the decking
into the marked v-grooves every other 40 cm, using the enclosed long screws.
Beware of the power of your electric screwdriver (see image 3).
TIP: for additional stability, the horizontal rails can
be screwed onto the vertical finishing profile using angle irons (see image
Step 4: When the first section is in place, place a
clip (C) on each rail, in the groove of the decking. Make sure they connect well
and then (semi-) tighten/untighten the clips to the rail, using the enclosed
short screws (see image 4). You can now install the second section and repeat
the above instructions until you have created the size of terrace you want. Once
the entire terrace is in place, tighten all screws and clips (beware of the
power of your electric screwdriver).
Step 5: Once the final section is in place, you finish with
a finishing profile (A-vertical) on both the longitudinal side and the so-called
crosscut face. Now cut the longitudinal side of the profile to be connected with
a false mitre. Note: follow the drawing (see images 7 and 8), so that the
finishing profile connects with the crosscut face later. Make sure that the
rails (A-horizontal) are cut to the right length, so that the decking slightly
protrudes (by about 8 mm) and the finishing profile connects nicely (see image
5). Now screw the finishing profile to the decking into the marked v-grooves
every other 40 cm, using the enclosed long screws (see image 5).
TIP: For an extra neat and strong attachment of the
finishing profile, we recommend you attach another bottom rail to the crosscut
faces of the bottom rail at a right angle, using the angle irons as described
under step 3. In that case you must keep the bottom rails 50 + 8 = 58 mm shorter
than the end of the last section of decking. Once the last section is in place,
you can fully secure the finishing profile (see image 10).
Before securing the finishing profile to the crosscut face, please note the
• make sure you "turn" the profile in relation to the profile on
the longitudinal side before you start cutting (see image 6).
• now follow
the drawing (see images 7 and 8), and cut the connecting finishing profile for
crosscut face with a false mitre.
• then screw the finishing profile
to the underlying rail into the marked v-groove every other 40
cm, using the
enclosed long screws (see image 6).
TIP: Beware of the power of your electric screwdriver.
Not suitable for load-bearing structures.