41. The foundations are a system of load bearing bed logs that support floor joists and tongue and groove timber floors. 42. Q : My basement is unfinished and I want to install fiberglass insulation between the exposed floor joists in the ceiling. 43. A typical floor joist is made from 2-by-10-inch lumber or from manufactured components containing plywood. 44. Small metal grilled openings at the base of the building serve to ventilate the crawl space beneath the first floor joists . 45. They involve beams, floor joists , ceiling joists ( those have to hold up only a ceiling ), and rafters. 46. Used as substitutes for plywood sheeting and solid wood floor joists and beams, these products make a house stronger and quieter. 47. The floors were composed of planks on loose sleepers that is, sleepers that were not fixed between the floor joists . 48. Q : There is a 4x8 beam running 16 feet across my basement ceiling to support the floor joists of the room above. 49. And a good inspector is going to crawl around in crawl spaces to check for damage to the support beams and floor joists . 50. The builder attaches wallboard to the underside of the floor joists of the story above and then applies paint or a textured coating.