A look at the framing. This is the basement underneath the fireplaces - the sloped wood there are inch thick oak boards that hold up the fireplace hearth extension. Main beams are ~ 6x7 (real) and made of Oak or Chestnut. Floor joists are 4x5in on 2 ft centers. The subfloor you can see is of5/8 boards varying in width up to 20+ inches, which we think may be recalimed from an older structure. The finsih flooring above is 1in x 12 pine.