Gaps are mandatory
The gap left between decking boards is a technical requirement, not an aesthetic choice. Timber expands across the grain as it takes up moisture; without a gap the boards push against each other and lift.
The gap also lets water pass through rather than pooling on the surface. A deck with no drainage tires quickly, however good the material.
The gap is set together with moisture
How much gap to leave depends on the moisture content at delivery. A board delivered dry will take up moisture and expand after installation, so it needs a larger gap.
The delivery moisture figure is therefore not just a record but a number that directly drives an installation decision.
The sub-frame matters as much as the surface
The frame the boards sit on has to breathe, and water must not collect underneath. Because the sub-frame is also outdoors, it should be made from impregnated material.
Support spacing is set together with board thickness: as thickness drops, supports get closer.
Profile and impregnation choice
Decking is produced finger-jointed and solid, with impregnation as an option. The impregnation colour — clear, green or brown — follows appearance preference.
Whether the profile is grooved or flat depends on the look you want and on cleaning habits. Share the intended conditions with the technical office and they can advise.