Concrete Slump Test - A cone is filled will concrete and filled pulled off.
Slumps
-True ✅
❌
-Shear: retest
-collapse
-Low Slump (1 to 2 inches): barely falls. For buildings
that need to hold their shape immediately, like a
curved curb on the side of a road
-Medium Slump (3 to 5 inches): Normal everyday
jobs like a backyard patio or a driveway.
-High Slump (6+ inches): Very runny, like water. Used
when concrete needs to be pumped through long
hoses or squeezed into tight wall molds filled with
steel bars.
The standard slump cone mold must be 12 inches
high, with an 8-inch base diameter and a 4-inch top
diameter. Concrete is packed into it in 3 equal layers,
tamping each layer 25 time
Concrete Tool sequence -Come-Along Rake: Rake used to pull and push
concrete just pumped out
-Screed Board (Straightedge): A long, perfectly
straight board or metal bar pulled
-Bull Float: A large, flat magnesium or aluminum
blade on a long extension pole
-Hand Mag Float (Magnesium Float)
Once its dried to finger test, Smooth top out.
Or Power Trowel (concrete helicopter)
The spinning pans smooth out high spots, fill in low
spots, and bring up the creamy cement paste.
-Trowel
Smooth out
Do not use excessive force
-Concrete Edger: A small tool with a curved L-shaped
lip.
-Groover (Jointer): A tool used to press straight lines
into the concrete slab at regular interval
-Broom: Drag a specialized stiff-bristled broom
across the firm surface
, CSLB Class B General Contractor's License - Building's Exam
Joint Spacing/depth -Thickness times 2 for minimum spacing. Times 3 for
maximum spacing
-2 to 3 feet per inch of slab thickness
Depth is 1/4 of thickness
4 joint types -Construction Joints
When huge concrete pours have to be broken up.
boundary between the old, cured concrete and the
fresh concrete poured later. Features like interlocking
keyways or steel dowel bars
-Control Joints
Straight lines press with a groover, cut with a saw.
Naturally cracks weak spot. Hidden at the bottom of
the groove instead of splintering across the surface
-Expansion Joints
full-depth gaps between concrete slabs that contain
filler material. Gets hot, concrete expands. Filler
absorb this movement. Stop buckle upward.
-Isolation joints
separate a concrete slab from any existing,
immovable structures. Different structures settle
differently. This joint lets the slab move up freely
without damaging existing structures.
Cutting joint Rules In hot climates within 12 hours of completion.
Curing times for Concrete -2/4 hours initial set reached, no going bcak
-7 days for heavey objects
-28 full cure, heavy machinery
Sill Plate Rules Foundation Grade Redwood, Preservative-Treated or
Pressure-Treated No. 2 or better
Thickness: Min 2 inches. Must not be smaller than
adjoining studs
Sill sealer thickness: 1/4
, CSLB Class B General Contractor's License - Building's Exam
Anchor bolts rules Hot-dipped galvanized
Minimum 2 bolts per plate
thickness: 1/2
Spacing: Max 6f, Min 1ft
Intendment: Min 7 inches
Ends: Max 1ft, Min 4inch
3 story or higher
5/8th inch anchor bolts
Wedge Anchors (Thunderstuds): You drill a hole,
hammer the bolt in, and tighten a nut.
-Flat Washer soft wood
-Split-Lock Washer machinery to stop a nut from
vibrating loose.
DON'T USE: A lock washer
Formula to calculate cubic yards of Length in feet × Width in feet × Thickness in feet) ÷
concrete 27. Add 5% to 10% for waste.
Standard concrete weight vs. Standard concrete weighs 150 lbs per cubic foot (with
Lightweight weight rebar). Lightweight concrete weighs 110 lbs per cubic
foot.
Max time limit to pour concrete after Concrete must be completely discharged from the
mixing truck mixer within 90 minutes or before the drum has
revolved 300 times.
Minimum footing depth in California Must extend below the local frost line, but minimum
depth is 12 inches below undisturbed ground surface
Minimum footing width for standard 1 1-story buildings require a minimum 12-inch wide
and 2-story buildings footing. 2-story buildings require a minimum 15-inch
wide footing.
Vapor barrier (Stego wrap) placement Placed directly under residential concrete slabs.
and thickness Minimum thickness required by CA green building
code is 10 mil (0.010 inches)
Foundation anchor bolt washers Standard flat washers are no longer allowed on sill
requirement plates in CA high-seismic zones. Must use minimum
3" x 3" x 1/4" thick structural steel plate washers.
, CSLB Class B General Contractor's License - Building's Exam
Rebar sizing scale and calculation Rebar sizes are designated by numbers that
represent the diameter in 1/8-inch increments.
Example:
#4 rebar = 4/8"= 1/2 diameter
#5 rebar = 5/8" diameter.
Rebar lap splice minimum overlap Standard rebar laps must overlap by a minimum of
length 30 times the bar diameter, or 15 inches, whichever is
greater. (For CSLB questions, 24 to 36 inches is the
typical range used for structural lap splices
depending on the concrete strength).
Maximum height concrete can be Concrete should not be dropped freely from a height
dropped freely greater than 3 to 5 feet to prevent segregation (where
heavy rocks separate from the creamy cement
paste).
Concrete Block (CMU) wall estimating Standard CMU blocks are 8" × 8" × 16".
multipliers
It takes exactly 1.125 blocks per square foot of wall
surface area.
It takes approximately 2/3 cubic foot of grout to fill the
cores of 100 square feet of standard block wall.
Stud Spacing Corner: Min of 3
Max unsupported height: 10ft
Max spacing
1Story: 24inch on center
2Story: 16 on center
3story: Not allowed on bottom floors
2/3Stories
2by6 or 3by4 Bottom levels must be 16inch on
center. Top level could be 24inch on center. Or 2by4's
on 16 center.
Story Placement
floor joists or roof rafters at 16 inches on center, but
your studs underneath are spaced at 24 inches on
center, the joists must rest within 5 inches of a
supporting stud below. If they are further away, a
double top plate is required to transfer the weight.