SOC Masonry Flashcards
- How should you take care of your tool while doing masonry work?
Wet tools before use
Rinse all tools with water frequently
Do not immerse dirty tools in water. The cement will cure underwater
- What are the dimension (nominal and actual) of a CMU/Cinder block?
Nominal 8 x 8 x 16 inches
Actual 7 5/8 x 7 5/8 x 15 5/8 inches
• 3/8 inch for mortar joint
- What are the size of a masonry joints?
3/8
- What is the weight range of a CMU block?
35-45 LBS
- What is the weight range of a cinder block?
25-35 LBS
- What is the difference between a cinder block and a CMU block?
CMU blocks are used for load bearing walls while cinder block are used for non-load bearing walls
- What are the two concrete block used in class?
Stretcher and corner
- What are the different factors affecting bond strength to take into account in the choice of a mortar?
TYPE (M,S,N, AND O) Quality Workability Water retention Surface texture Quality of laying the blocks
- What are the desirable properties of a mortar?
Plasticity
Water retention
Strength and Durability
- Mortar is produced using what?
Masonry cement
Portland cement
* when Portland cement is used, masonry lime must use
- What are the different types of mortar?
M - 2500 psi, Below grade; load bearing, chimneys/manholes
S - 1800 psi, below grade, foundation walls sewers
N - 750 psi, general purpose above grade; interior or exterior, load bearing (normal)
O - 350 psi, used for non-load-bearing (pointing)
- What are the two types of mixing?
Machine mixing
Hand mixing
- What is the procedure for machine mixing?
First, add most of the water and half the sand Next, add the masonry cement and the rest of the sand Mix continuously for one minute Slowly add the rest of the water until proper consistency is achieved
Should be used whenever possible
Mixing time 3 mins (may be extended to 5)
- How do we want the sand to be?
Damp and loose
- What are the two categories of sand?
Manufactured and Natural
- What is special requirement for water?
Same as concrete; Must be free of large amount of dissolved salt
- What is used for Accelerators?
Calcium Chloride (not more than 2 percent by weight, do not use for steel reinforced masonry)
- What is Re-termpering mortar?
Workability of mortar can be restored by adding water to stiffened mortar
- How should mortar material be stored?
All mortar material except sand and line in a dry place. Sand and lime should be covered to prevent moisture loss.
- What is wall consist of?
Corner/end Field Control / expansion joints Wall intersections Rough opening (door and windows)
- What is first course?
- Locate the corners
- Lay mortar bed
- Lay block on all corners first
- Insure all blocks are leveled and plumb
- Insure all mortar joints are filled and tooled
Laying block between corners (Line block+mason twine)
Closure block
Reinforce
Control joints
- What size of a gap should you leave for the closure block?
Minimum 16 1/2 inch space (butter both ends)
- What type of wood should you use when in contact with masonry?
Pressure treated Isolate with moisture barrier to prevent moisture loss
- Should you interlock course between load bearing and non-bearing walls?
No
- What are the two types of lintel?
Constructed
Precast
- What are two type of finishing action?
Tooling/Striking
Patching
- How should you be striking?
Vertical then horizontal
- What are Load bearing walls
Load bearing walls are crucial to hold up building, where non-load bearing wall is secondary support joint.
- What is the rule of thumb for the placement of control joints?
No more than 25 feet between the joints
No thicker than 1/2 inch
- What are the two types of finishing joints?
Concave joint
V-joint
- How many bricks make a pallet?
525 Bricks
- How many CMU blocks make a pallet?
94 CMU Block
- Can you use calcium chloride when working with steel reinforced masonry?
No
- When tying walls together what is the vertical distance between metal ties?
4 ft
- Formula for estimating masonry block
Linear Feet x Height x 1.125 x Number of Structures =Total # of blocks
LF = 2 (L + W)
- Formula estimating bags of masonry cement
(Number of Blocks) x 3 / 100 = Bags of Cement
- Formula estimating for tons of masonry sand and water
1 ton of sand per 8 bags of masonry cement
-or-
Bags of cement ÷ 8 = tons of sand
8 x bags = gallons of water
- How to find CMU for non-American standard concrete Block?
144 / ( H+3/8) X (L+3/8)
3/8 is width of masonry joint
What does CMU stand for?
Concrete Masonry Unit
What are the types of Masonry Units
Hollow - Load-bearing and Non-load bearing
Solid - Brick and Block
Recipe for Mortar
Masonry Cement (or Portland with Lime)
Masonry Sand
Water
Steps to hand mix mortar
Used to mix small amounts or when
machine is not available.
Use a leak proof mortar box or other
suitable container.
Place sand in first, and then place all other
materials on top.
Mix all dry material first before adding water.
Laying the corners
Build up the corners 4 or 5 courses high.
Step each course back one-half block.
Mortar for horizontal joints is applied to the
top of the course previously laid.
Apply mortar for the vertical joints to either
the block being laid or to the block
previously laid.
Laying blocks between corners
Stretch a mason’s line between corners on the
exterior edge of the wall.
Lay the outside top edge of each block to this
line.
Align each block to mason’s line by tapping with
a trowel handle.
Check level, Plumb, square, rack and make all adjustments to blocks while mortar is still soft and plastic.
Types of reinforcement
Rebar
Latter (Wire)
Anchor Bolts
Used to fasten timber or metal framing to
masonry foundation
Place metal lath in the second horizontal
mortar joint from the top of the wall under
the cores that will contain the bolts.
Place 1/2” x 18” bolts in cores, and space
them not more than 4 feet apart.
Fill cores containing bolts with concrete or
mortar.
How far should anchor bolts be spaced?
Less than 4 feet apart
Control Joint
Sometimes called expansion joints Breaks up the masonry work into panels Joint is a continuous space where masonry does not touch Used to prevent extensive cracking from one panel to another
Placement rule of thumb= No greater than
25’ between joints; No thicker than ½”
What are the two ways to tie in load-bearing and non-load-bearing walls?
Metal ties
1/4 inch galvanized mesh
Modular Coordination
When the design of a building, its components, and the building material units all conform to a dimensional
standard based on a modular system.
Modular Measure
The system of dimensional standards for buildings and building components that permit field assembly without cutting.
What does planning save?
Considerable:
Time
Labor
Materials
Lintels
Lintels are used to support masonry block over modular openings such as doors and windows in walls.
Sills
Sills are used to create a finished look for the bottoms of openings in walls. They are usually precast and installed following wall construction.
When can you begin tooling/striking?
When mortar is “thumbprint hard”
Formula estimating for water
8 gallons per 1 bag of masonry cement
-or-
Bags of cement x 8 = gallons of water
