2025 IRC EXAM - IRC CHAPTER 5 – FLOORS
QUESTIONS WITH CORRECT ANSWERS
2025
ATminimum design load of shall be used for the determination of the maximum allowable flo
or joist spans in attics that are accessed by a fixed stairway. - correct answer-30 psf
Where not supported on a ribbon strip, the ends of floor joists shall bear a minimum of on w
ood or metal. - correct answer-1 1/2 inches
R502.6 Bearing
Floor cantilever ratio of back span to cantilever span:
- where supporting a bearing wall and a roof: :
- where only supportingTan exterior balcony: : -Tcorrect answer-3:1
2:1
R502.3.3 Floor cantilevers
For cantilevered floor joists, regardless of loading conditions a maximum span equal to the is per
mitted. - correct answer-depth of the floor joists
R502.3.3 Floor cantilevers
Where piping or vents penetrate the floor system, joists may be and to allow the pip
e or vent to pass through. Solid blocking between the joists at ft intervals is required so that the
two joists will function as a combined member without twisting. - correct answer-doubled
separated
4 ft
R502.4 Joists under bearing partitions.
, Rim joists can be braced laterally by or at the end points and spac
ed at intervals of feet. - correct answer-solid blocking
diagonal bridging
8 ft
R502.7 Lateral restraint at supports
Draftstopping shall be installed to floor framing members, unless approved by a building of
ficial. - correct answer-parallel
R502.12 Draftstopping.
Concrete slab-on-
ground floors require a inch thick gravel base course where the slab is .-
correct answer-4 inch
below grade
(exception if slab is on well-draining soils)
R506.1 Concrete slab-on-ground floors.
Reinforcement for slabs-on-
ground shall be supported to remain in place during the concrete placement from the to the
of the slab. - correct answer-middle, upper third
R506.2.4TReinforcement support.
Deck vertical loads shall be transferred to with . - correct answer-
band joists, ledgers
R507 Exterior decks.
QUESTIONS WITH CORRECT ANSWERS
2025
ATminimum design load of shall be used for the determination of the maximum allowable flo
or joist spans in attics that are accessed by a fixed stairway. - correct answer-30 psf
Where not supported on a ribbon strip, the ends of floor joists shall bear a minimum of on w
ood or metal. - correct answer-1 1/2 inches
R502.6 Bearing
Floor cantilever ratio of back span to cantilever span:
- where supporting a bearing wall and a roof: :
- where only supportingTan exterior balcony: : -Tcorrect answer-3:1
2:1
R502.3.3 Floor cantilevers
For cantilevered floor joists, regardless of loading conditions a maximum span equal to the is per
mitted. - correct answer-depth of the floor joists
R502.3.3 Floor cantilevers
Where piping or vents penetrate the floor system, joists may be and to allow the pip
e or vent to pass through. Solid blocking between the joists at ft intervals is required so that the
two joists will function as a combined member without twisting. - correct answer-doubled
separated
4 ft
R502.4 Joists under bearing partitions.
, Rim joists can be braced laterally by or at the end points and spac
ed at intervals of feet. - correct answer-solid blocking
diagonal bridging
8 ft
R502.7 Lateral restraint at supports
Draftstopping shall be installed to floor framing members, unless approved by a building of
ficial. - correct answer-parallel
R502.12 Draftstopping.
Concrete slab-on-
ground floors require a inch thick gravel base course where the slab is .-
correct answer-4 inch
below grade
(exception if slab is on well-draining soils)
R506.1 Concrete slab-on-ground floors.
Reinforcement for slabs-on-
ground shall be supported to remain in place during the concrete placement from the to the
of the slab. - correct answer-middle, upper third
R506.2.4TReinforcement support.
Deck vertical loads shall be transferred to with . - correct answer-
band joists, ledgers
R507 Exterior decks.
