Ok, we're in discussions now with the builder and hardwood supplier on plank width. This is new construction. In-floor radiant...not a staple-up.

Builder and hardwood supplier (highly respected guru) prefer a 2 1/4 width board to a max of 3 inches. This will be conventionally installed T & G, and the material is IPE.

Their concerns with wider widths are potentially larger gaps with the temp changes. My preference, at least on the main-level great room is a 4 inch width simply due to the size of the room (700 square feet, 9 foot ceilings). I'm thinking this is not as big an issue as it would seem with respect to gap size due to expansion/contraction. What are your thoughts?