Do the decking boards need to be spaced apart or placed tight together during installation?
The answer to that depends on the type of material being used for the decking surface. All of the composite decking materials require a small gap between the boards side to side and end to end. These materials expand and contract based upon the outside temperature and require space for that movement. On the other hand, when installing pressure treated wood, it is best to install the boards tight together. Unless kiln dried after treatment, these boards are usually still wet from the pressure treatment process and have swelled due to the high moisture content. After several weeks, the wood dries and actually shrinks creating a small gap between the boards.
