Choice of variety is very important. This is some selection criterion to help you find good quality wooden planks

• Durability ( durability against damage factor) : every variety of wood is characterized by class from 1 to 5, allowing to know it’s utilization.
  Generally, wood used for outdoor terrace must be class 4.
  Resinous tree (pine, larch, douglas, …) must have undergoes autoclave treatment allowing it to be protected against biological attack (mushroom, bugs, …). Tropical wood doesn’t require to be treated because they are naturally treated.
• Drying : you must choose a wood having undergone a KD drying process (kiln – dried) that mean dried by a dryer so that the hydrometry rate was equal or lower than 18%, contrary to the AD drying process (Air Dried). KD dried wood get closer to the normal use wich is imortant to obtain for an optimal installation on longevity of your terrace.
• Solidity and budget : Tropical varieties are denser ans consequently durable (For example : denser, leave no marks when an object fall on it, contrary to pine wood)
  Pine wood get an excellent price-quality ratio. Look at the “Choice of costing” section in the calculator help for more details

We have 3 different variety of wood : pine wood (28 mm thickness) and for tropical wood we have Itauba and garapa. Our system is compatible with composite, however we do not offer any for sale.
For information : the structure can be sold alone

The only recommendation to follow is the distance between 2 joist (read the manufacturer recommendation).
We can include adapted screws for different clip’s brand (TREX, SILVADEC, GEOLAM, NMC, FIBERDECK …)

There isn’t contradiction in relation to the structure, in this case, the best is to call on an electrical professional.