Construction Means, Methods, and Materials
This domain tests whether you know how the work is actually built and what inspection or testing proves it was built correctly: soils and compaction, concrete, masonry, steel, wood framing, envelope, and finishes.
Soils and concrete
Structural fill is placed in lifts (commonly 6–8 in) and compacted to a specified percentage of maximum dry density from a proctor test, verified by field density tests. Concrete is specified by 28-day compressive strength (f'c); slump and air tests are done at placement, and cylinders are cast for acceptance. Water added in the field raises the water-cement ratio and lowers strength - adjust with admixtures, not the hose. Curing maintains moisture and temperature; it is not the same as drying.
Joints, masonry, and envelope
Control joints relieve shrinkage and are spaced roughly 24–30 times slab thickness, with panels kept close to square and joints at re-entrant corners. Masonry needs flashing and weep holes at the base of cavities. Steel connections are bolted or welded per the structural documents, with inspection and certifications. The weather barrier laps shingle-style, and flashing details at penetrations and transitions shed water outward.
Worked example
Specify control-joint spacing for a 5-in slab on grade. 24 × 5 = 120 in = 10 ft; 30 × 5 = 150 in = 12.5 ft. Space joints at 10–12.5 ft on center, keep panels no more than about 1.5:1 in aspect ratio, and place joints at columns and re-entrant corners. Saw-cut within the window before random cracking begins - typically within 6–12 hours.
Traps that cost marks
- Adding water to raise slump instead of using a water reducer.
- Testing compaction on lifts that are too thick to compact uniformly.
- Omitting weep holes and through-wall flashing.
- Lapping weather barriers the wrong direction so water is trapped.
- Saw-cutting joints too late, after shrinkage cracks have formed.