Strict boards are used for floors.
Lags are laid on brick columns; the thickness of the floorboard is from 3.2 to 3.7 cm, width from 8 to 12 cm;
Lags are laid out by reinforced concrete floors on soundproofing gaskets, the sizes of the boards should be like this: thickness from 2.5 to 3.2 cm, width from 8 to 12 cm.