Decking screw for mounting pressure impregnated timber. C4 outdoor The screw is CE-marked and C4 + classified. The screw is waxed, which reduces the tightening torque while the wax provides extra rust protection. Application Decking screw C4 pro is intended for mounting decking timber etc. against wooden frames outdoors. For very exposed environments or structures with a lot of movement, such as marine environments, pool areas, fences, stairs, railings, etc. we always recommend decking screws made of stainless or acid-resistant material. NOTE! When installing teak-like decking timber such as Cumaru, Kirai etc. and Siberian larch, we always recommend decking screws of stainless steel quality, as well as pre-drilling. Calculation of consumption In order to calculate how many screws you need for your project, you need to know the width of the timber and your intended rule distance. Below you can see the consumption for the most common dimensions and distances. Timber width / Rule distance / Number of screws/m2 95 mm / 600 mm / 34 pcs 120 mm / 600 mm / 28 pcs 140 mm / 600 mm / 24 pcs