What is the difference between glueing, secret nailing and floating? And how does the width of the board effect the method you use?
Glueing = fully bonding the wood to the subfloor
Secret Nailing = nailing floorboard in 45 angle to batten (at least 4cm thick) or joist
Floating = installing underlayment first on subfloor, installing floorboard 'floating' on the underlayment and glueing the T&G's.
Glueing is mostly used with design parquet floors and strip floorboards (narrow boards up to 100mm) or when you have many small lengths of wider boards. Most manufacturers recommend glueing down all floor types when UFH is involved to prevent air-pockets.
Secret nailing: when installing directly onto joists (or sometimes on a subfloor of thick enough plywood - never nail on chipboard, this will split).
Floating: most solid and wood-engineered boards can be installed floating. Note for solid: as long as the width of the room is not wider than 5 - 6 meters, otherwise it is best to glue to solid floorboards.